Likelihood ratio: A powerful tool for incorporating the results of a diagnostic test into clinical decisionmaking

Prevalence and predictors of radiographic pneumonia in children with wheeze: A systematic review and meta-analysis

BACKGROUND

Diagnostic uncertainty exists surrounding the identification of radiographic pneumonia in children with wheeze. It is important to determine the prevalence and clinical predictors of pneumonia in this population to limit chest radiography (CXR) and promote judicious antibiotic use.

OBJECTIVES

The objectives were to (1) estimate the prevalence of radiographic pneumonia in children with wheeze and (2) systematically review the diagnostic accuracy of clinical findings for the identification of radiographic pneumonia.

METHODS

Data sources were MEDLINE, PubMed Central, Cochrane Library, CINAHL, and Web of Science (January 1995 to September 2023). For study selection, two reviewers identified high-quality studies reporting on clinical characteristics associated with radiographic pneumonia in wheezing children (age 0-21 years). Using Covidence software, data regarding study characteristics, methodologic quality, and results were extracted. Data were pooled using random-effects meta-analysis.

RESULTS

A total of 8333 unique titles and abstracts were reviewed. Twelve studies, representing 7398 patients, were included. Fifteen percent of children with wheeze undergoing CXR had pneumonia. Findings associated with radiographic pneumonia included temperature ≥ 38.4°C (positive likelihood ratio [LR+] 2.1, 95% CI 1.2-3.6, specificity 85%), oxygen saturation < 92% (LR+ 3.6, 95% CI 1.4-8.9, specificity 89%), and grunting (LR+ 2.7, 95% CI 1.6-4.4, pooled specificity 91%). Factors associated with the absence of radiographic pneumonia included lack of fever (negative likelihood ratio [LR-] 0.67, 95% CI 0.52-0.85) and oxygen saturation ≥ 95% (LR- 0.64, 95% CI 0.42-0.98). Tachypnea and auscultatory findings were not associated with radiographic pneumonia.

DISCUSSION

Heterogeneity across studies limits generalizability. Additionally, all included studies overestimate the rate of radiographic pneumonia given the fact that all subjects had a CXR performed due to clinical suspicion of pneumonia.

CONCLUSIONS

Radiographic pneumonia occurs in 15% of wheezing children undergoing CXR for pneumonia. Auscultatory findings and tachypnea do not differentiate children with and without pneumonia, and the rate of radiographic pneumonia is very low in the absence of fever and hypoxemia.

Prognostic Performance of the Maximal Systolic Acceleration at the Hallux in Healing of Foot Ulcers: A Retrospective Cohort Study

BACKGROUND

The accurate prediction of foot ulcer healing remains a major challenge in clinical practice. To date, no reliable bedside tests are available. The primary aim of this study was to determine the prognostic performance of the maximal systolic acceleration (ACCmax) to predict ulcer healing. Secondary objectives comprised the investigation of the prognostic accuracy in patients prone to medial arterial calcification and to assess the potential risk of amputation.

METHODS

A single-center retrospective cohort study was conducted. Patients aged ≥18 years who presented with a new-onset ulcer (i.e. Fontaine IV and neuropathic ulcers) on the foot and underwent an ACCmax measurement at the hallux were included. Ulcer healing was defined as an intact skin with epithelialization after 3 or 12 months of follow-up. Prognostic performance was calculated by using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR).

RESULTS

In total, 136 patients with 143 wounds were included. Almost half of the patients were diagnosed with diabetes mellitus (47%), and wound infection was present in 42% of cases. After 3 months of follow-up, an NPV of 97.9%, PLR of 3.25, and NLR of 0.19 were found when applying an ACCmax threshold of 0.5 m/s2. When looking at 12 months, these numbers were 85.6%, 2.72, and 0.50, respectively. Subgroup analysis for patients with diabetes mellitus and chronic kidney disease showed comparable results. The risk of amputation increased significantly when a measurement below 1.0 m/s2 was present (odd ratio 5.3, P = 0.010).

CONCLUSIONS

ACCmax measurements at the hallux can have additional prognostic value in patients with foot ulcers. An ACCmax below 1.0 m/s2 is associated with nonhealing of an ulcer and a higher risk of amputation, while higher ACCmax values are associated with limb salvage. Therefore, ACCmax could be used for grading ischemia in a wound classification system.

Beyond type 2 asthma biomarkers: risk stratification for NSAID-exacerbated respiratory disease

Introduction

Type 2 (T2) asthma is often associated with chronic rhinosinusitis with nasal polyposis (CRSwNP). Additionally, nonsteroidal anti-inflammatory drug (NSAID) intolerance leads to NSAID-exacerbated respiratory disease (N-ERD). Previous transcriptomic data in non-CRSwNP T2 asthma patients showed differentially expressed genes. We focused on ALOX15, CLC, CYSLTR2, HRH4 and SMPD3 to investigate their role in T2 asthma.

Methods

The study included 100 healthy controls and 103 T2 asthma patients, divided into patients with asthma (n=54), patients with asthma and CRSwNP (n=29) and patients with N-ERD (n=20). Quantitative PCR analysis was performed on blood-derived RNA samples first to validate the five differentially expressed genes. The data were further analysed to find potential associations and biomarkers.

Results

Patients, regardless of stratification, exhibited significantly higher gene expression than healthy controls. The patterns of association revealed that ALOX15 was exclusively present in the non-comorbidity group, SMPD3 and CLC in the comorbidity groups, and HRH4 in all patient groups. ALOX15, CYSLTR2 and SMPD3 expression showed potential as biomarkers to confirm the diagnosis of T2 asthma using peripheral blood eosinophils as the initial criterion. Peripheral blood eosinophils combined with gene expression, especially SMPD3, may improve the diagnosis. CLC and CYSLTR2 expression play a specific role in discriminating N-ERD.

Discussion

We validated the transcriptomic data of five differentially expressed genes in T2 asthma. Different patterns of association were identified in patient stratification, suggesting that different molecular mechanisms underlie the spectrum of T2 asthma. Potential biomarkers were also found and used to design an algorithm with practical diagnostic utility for T2 asthma, including risk stratification for N-ERD.

Delirium detection in the emergency department: A diagnostic accuracy meta-analysis of history, physical examination, laboratory tests, and screening instruments

INTRODUCTION

Geriatric emergency department (ED) guidelines emphasize timely identification of delirium. This article updates previous diagnostic accuracy systematic reviews of history, physical examination, laboratory testing, and ED screening instruments for the diagnosis of delirium as well as test-treatment thresholds for ED delirium screening.

METHODS

We conducted a systematic review to quantify the diagnostic accuracy of approaches to identify delirium. Studies were included if they described adults aged 60 or older evaluated in the ED setting with an index test for delirium compared with an acceptable criterion standard for delirium. Data were extracted and studies were reviewed for risk of bias. When appropriate, we conducted a meta-analysis and estimated delirium screening thresholds.

RESULTS

Full-text review was performed on 55 studies and 27 were included in the current analysis. No studies were identified exploring the accuracy of findings on history or laboratory analysis. While two studies reported clinicians accurately rule in delirium, clinician gestalt is inadequate to rule out delirium. We report meta-analysis on three studies that quantified the accuracy of the 4 A's Test (4AT) to rule in (pooled positive likelihood ratio [LR+] 7.5, 95% confidence interval [CI] 2.7-20.7) and rule out (pooled negative likelihood ratio [LR-] 0.18, 95% CI 0.09-0.34) delirium. We also conducted meta-analysis of two studies that quantified the accuracy of the Abbreviated Mental Test-4 (AMT-4) and found that the pooled LR+ (4.3, 95% CI 2.4-7.8) was lower than that observed for the 4AT, but the pooled LR- (0.22, 95% CI 0.05-1) was similar. Based on one study the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) is the superior instrument to rule in delirium. The calculated test threshold is 2% and the treatment threshold is 11%.

CONCLUSIONS

The quantitative accuracy of history and physical examination to identify ED delirium is virtually unexplored. The 4AT has the largest quantity of ED-based research. Other screening instruments may more accurately rule in or rule out delirium. If the goal is to rule in delirium then the CAM-ICU or brief CAM or modified CAM for the ED are superior instruments, although the accuracy of these screening tools are based on single-center studies. To rule out delirium, the Delirium Triage Screen is superior based on one single-center study.

Influence of repeated mastitis on the milk production and metabolic status in the subsequent lactation period of dairy cattle

Recurrent mastitis poses a common challenge on dairy farms. While the impact of repeated mastitis within the same lactation has been investigated, the difference from one lactation to the next, particularly concerning the change of milk and blood metabolites, remains unclear. This study aimed to examine the difference in milk yield, milk composition, and metabolic status in the subsequent lactation between healthy and repeated mastitis in the previous lactation. The study population comprised 50 cows chosen from 400 cows, with 25 having no history of mastitis and 25 experiencing mastitis more than three times during the last lactation. Following dry-off and calving, all cows initiated a new lactation, during which no mastitis was diagnosed until the sample collection period. In the group exposed to repeated mastitis, a significant decrease in milk fat levels was observed in the subsequent lactation, while no change was observed in milk somatic cell count (SCC). Milk collected from cows that had experienced repeated mastitis in the previous lactation exhibited significant increases in the levels of free amino acids, namely valine, proline, and alanine. However, no difference in plasma levels of these amino acids was noted. These results indicate that individuals exposed to repeated mastitis have persistent milk quality changes even after dry-off. Biomarker analysis suggested that the milk valine and proline showed a moderate biomarker potential on Kappa coefficients to characterize cows that have experienced repeated mastitis. Furthermore, the results of biomarker combinations for valine and proline provided the highest specificity (100 %), positive likelihood ratio (infinity), and substantial biomarker potential on kappa coefficients (0.68). These findings significantly enhance our understanding of the pathobiology and etiology of recurrent mastitis and provide a biomarker to characterize cows that have experienced repeated mastitis in the past.

Diagnostic accuracy of the maximal systolic acceleration to detect peripheral arterial disease

BACKGROUND

Diagnosing peripheral arterial disease (PAD) can be challenging owing to medial arterial calcification (MAC) in patients with diabetes mellitus (DM) and chronic kidney disease (CKD). Current bedside tests, such as the ankle-brachial index and toe-brachial index, are often insufficient. The maximal systolic acceleration (ACCmax) is a velocimetric Doppler-derived parameter and could be a new promising test in the diagnostic workup of these patients. The primary aim of this study was to evaluate the diagnostic performance of the ACCmax to detect PAD.

METHODS

A retrospective cohort study was performed in a tertiary referral hospital. Patients ≥18 years old with suspected PAD who underwent ACCmax measurement(s) along with computed tomography angiography of the abdominal aorta and lower extremities (reference test) were eligible for inclusion. ACCmax measurements of the posterior tibial artery, anterior tibial artery and peroneal artery were collected. Diagnostic performance was assessed by using sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and area under the curve (AUC).

RESULTS

In total, 340 patients (618 limbs) were included. Approximately 40% suffered from DM and 30% had CKD. Diagnostic performance of the ACCmax to detect PAD for the posterior tibial artery showed a sensitivity of 90%, specificity of 93%, positive likelihood ratio of 12.83, and negative likelihood ratio of 0.11 (AUC, 0.953). For the anterior tibial artery, these results were 94%, 97%, 32.06, and 0.06 (same sequence as presented before) with an AUC of 0.984. The peroneal artery had a performance of 86%, 89%, 7.51, and 0.16, respectively (AUC, 0.893). Diagnostic accuracy of the ACCmax did not diminish in subgroup analysis for patients with DM or CKD.

CONCLUSIONS

The ACCmax showed excellent diagnostic performance to detect PAD, independent of patients prone to medial arterial calcification.

Diagnostic Accuracy of Abdominal CT for Locally Advanced Colon Tumors: Can We Really Entrust Certain Decisions to the Reliability of CT?

Many different options of neoadjuvant treatments for advanced colon cancer are emerging. An accurate preoperative staging is crucial to select the most appropriate treatment option. A retrospective study was carried out on a national series of operated patients with T4 tumors. Considering the anatomo-pathological analysis of the surgical specimen as the gold standard, a diagnostic accuracy study was carried out on the variables T and N staging and the presence of peritoneal metastases (M1c). The parameters calculated were sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios, as well as the overall accuracy. A total of 50 centers participated in the study in which 1950 patients were analyzed. The sensitivity of CT for correct staging of T4 colon tumors was 57%. Regarding N staging, the overall accuracy was 63%, with a sensitivity of 64% and a specificity of 62%; however, the positive and negative likelihood ratios were 1.7 and 0.58, respectively. For the diagnosis of peritoneal metastases, the accuracy was 94.8%, with a sensitivity of 40% and specificity of 98%; in the case of peritoneal metastases, the positive and negative likelihood ratios were 24.4 and 0.61, respectively. The diagnostic accuracy of CT in the setting of advanced colon cancer still has some shortcomings for accurate diagnosis of stage T4, correct classification of lymph nodes, and preoperative detection of peritoneal metastases.

Development and validation of a pentaplex assay for the identification of antibodies against common viral diseases in cattle

Animal welfare and economic implications of infectious diseases in cattle demand an efficient surveillance as the foundation for control and eradication programmes. Bovine respiratory syncytial virus (BRSV), Parainfluenza virus type 3 (PI3V), Bovine herpes virus-1 (BoHV-1), Bovine viral diarrhoea virus (BVDV), and Enzootic bovine leukosis virus (EBLV) cause common and often underdiagnosed diseases in cattle that are endemic in most countries [1]. A hallmark of individual exposure to a viral pathogen is the presence of antibodies directed towards that virus. The aim of this study was to develop and validate a pentaplex assay to simultaneously detect and quantify antibodies against BRSV, PI3V, BoHV-1, BVDV and EBLV in serum, as an efficient tool to yield epidemiological data. Monoplex assays were initially developed using either complete BRSV or BoHV-1 viral lysates, or recombinant proteins for BVDV, EBLV or PI3V as capture antigens. In addition, 125 serum samples from unvaccinated cattle, which were classified as positive or negative for each of the viruses by commercial ELISA kits, were used for validation. Conditions established for the Luminex monoplex assays were adopted for the pentaplex assay. The accuracy, determined by the area under the ROC curve, was greater than 0.97, and assay diagnostic sensitivities and specificities were over 95 and 90%, respectively, for all antigens. Intra (r) and interassay (R) coefficients of variation were under 10 and 20 %, respectively. Selectivity towards target viruses was shown by binding inhibition assays where unbound viruses reduced fluorescence intensities. Diagnostic agreement for samples analysed simultaneously in the monoplex and multiplex assays was almost perfect. In conclusion, a highly sensitive pentaplex assay was validated for the simultaneous identification of antibodies directed against BVDV, BoHV-1, PI3V, BRSV and EBLV in serum. The developed pentaplex assay complies with performance characteristics established by international guidelines for diagnostic tests and may be used as a tool for the implementation of epidemiological surveillance.

Relative diagnostic accuracy of point-of-care tests to rule-in Dirofilaria immitis infection in clinically suspect dogs: A systematic review and meta-analysis

Canine heartworm, Dirofilaria immitis, can cause severe disease and sometimes death of the host. Associated clinical signs, lack of preventative usage and regional endemicity are unlikely sufficient by themselves to reach a definitive diagnosis. Several point-of-care (POC) diagnostic tests are commercially available to aid in-clinic diagnosis, however, there is variable diagnostic accuracy reported and no synthesis of published evidence. This systematic review aims at meta-analysing the likelihood ratio of a positive result (LR⁺) to inform the selection and interpretation of POC tests in practice to rule-in heartworm infection when there is clinical suspicion. Three literature index interfaces (Web of Science, PubMed, Scopus) were searched on November 11th, 2022, for diagnostic test evaluation (DTE) articles assessing at least one currently commercialised POC test. Risk of bias was assessed adapting the QUADAS-2 protocol and articles with no evidence of high risk of bias were meta-analysed if deemed applicable to our review objective. Substantial between DTE heterogeneity was investigated including potential threshold or covariate effects. A total of 324 primary articles were sourced and 18 were retained for full text review of which only three had low risk of bias in all four QUADAS-2 domains. Of the nine heartworm POC tests evaluated, only three, IDEXX SNAP (n DTEs = 6), Zoetis WITNESS (n DTEs = 3) and Zoetis VETSCAN (n DTEs = 5) could be analysed. Both WITNESS and VETSCAN DTEs showed substantial heterogeneity due to a putative threshold effect and no summary point estimates could be reported. SNAP DTEs showed acceptable heterogeneity, and a summary LR⁺ was estimated at 559.0 (95%CI: 24.3-12,847.4). The quality and heterogeneity of heartworm POC test DTEs was highly variable which restricted our summary of the diagnostic accuracy to only the SNAP test. A positive result from the SNAP test provides strong evidence of the presence of an infection with adult heartworm(s) in a dog patient and this test is warranted to rule-in clinical suspicion(s) in clinics. However, our review did not appraise the literature to assess the fitness of SNAP test, or any other POC tests, to rule-out heartworm infection in dogs without clinical suspicion or following heartworm therapy.

Low Phase Angle Values Are Associated with Malnutrition according to the Global Leadership Initiative on Malnutrition Criteria in Kidney Transplant Candidates: Preliminary Assessment of Diagnostic Accuracy in the FRAILMar Study

Malnutrition has a negative impact on patients with chronic diseases and its early identification is a priority. The primary objective of this diagnostic accuracy study was to assess the performance of the phase angle (PhA), a bioimpedance analysis (BIA)-derived parameter, for malnutrition screening using the Global Leadership Initiative for Malnutrition (GLIM) criteria as the reference standard in patients with advanced chronic kidney disease (CKD) waiting for kidney transplantation (KT); criteria associated with low PhA in this population were also analyzed. Sensitivity, specificity, accuracy, positive and negative likelihood ratios, predictive values, and area under the receiver operating characteristic curve were calculated for PhA (index test) and compared with GLIM criteria (reference standard). Of 63 patients (62.9 years old; 76.2% men), 22 (34.9%) had malnutrition. The PhA threshold with the highest accuracy was ≤4.85° (sensitivity 72.7%, specificity 65.9%, and positive and negative likelihood ratios 2.13 and 0.41, respectively). A PhA ≤ 4.85° was associated with a 3.5-fold higher malnutrition risk (OR = 3.53 (CI95% 1.0-12.1)). Considering the GLIM criteria as the reference standard, a PhA ≤ 4.85° showed only fair validity for detecting malnutrition, and thus cannot be recommended as a stand-alone screening tool in this population.

Diagnostic accuracy of the Enferplex Bovine Tuberculosis antibody test in cattle sera

Bovine tuberculosis is a contagious bacterial disease of worldwide economic, zoonotic and welfare importance caused mainly by Mycobacterium bovis infection. Current regulatory diagnostic methods lack sensitivity and require improvement. We have developed a multiplex serological test for bovine tuberculosis and here we provide an estimate of the diagnostic accuracy of the test in cattle. Positive and negative reference serum samples were obtained from animals from Europe and the United States of America. The diagnostic specificity estimate was 98.4% and 99.7% using high sensitivity and high specificity settings of the test respectively. Tuberculin boosting did not affect the overall specificity estimate. The diagnostic sensitivity in samples from Mycobacterium bovis culture positive animals following tuberculin boosting was 93.9%.The relative sensitivity following boosting in tuberculin test positive, lesion positive animals and interferon gamma test positive, lesion positive animals was 97.2% and 96.9% respectively. In tuberculin test negative, lesion positive animals and in interferon gamma test negative, lesion positive animals, the relative sensitivity following tuberculin boosting was 88.2% and 83.6% respectively. The results show that the test has high diagnostic sensitivity and specificity and can detect infected animals that are missed by tuberculin and interferon gamma testing.

Probabilistic graphical model for the evaluation of the emotional and dramatic personality disorders

Personality disorders are psychological ailments with a major negative impact on patients, their families, and society in general, especially those of the dramatic and emotional type. Despite all the research, there is still no consensus on the best way to assess and treat them. Traditional assessment of personality disorders has focused on a limited number of psychological constructs or behaviors using structured interviews and questionnaires, without an integrated and holistic approach. We present a novel methodology for the study and assessment of personality disorders consisting in the development of a Bayesian network, whose parameters have been obtained by the Delphi method of consensus from a group of experts in the diagnosis and treatment of personality disorders. The result is a probabilistic graphical model that represents the psychological variables related to the personality disorders along with their relations and conditional probabilities, which allow identifying the symptoms with the highest diagnostic potential. This model can be used, among other applications, as a decision support system for the assessment and treatment of personality disorders of the dramatic or emotional cluster. In this paper, we discuss the need to validate this model in the clinical population along with its strengths and limitations.

Likelihood Ratios: An Important Concept for Palliative Physicians to Understand

Palliative care has several tools and questionnaires which are commonly used for patient-related outcomes and prognosis. As an example, the Surprise Question (I would or would not be surprised that this person would have died in a year) has been used as a screen for palliative care referral but also used as a prognostic tool. Diagnostic tests, prognostic tools, and tools for gauging outcomes have certain sensitivity and specificity in predicting a diagnosis or outcome. Clinicians often use positive and negative predictive values in judging the merits of a diagnostic tool or questionnaire. However positive and negative predictive values are highly dependent on the prevalence of disease or outcome in a population and thus are not portable across studies. Likelihood ratios are both portable across populations but also provide the strength of the diagnostic or predictive measure of a test or questionnaire. In this article, we review the value and limitations of likelihood ratios and illustrate the value of using likelihood ratios using 3 studies centered on the Surprise Question published in 2022.

Machine learning and LACE index for predicting 30-day readmissions after heart failure hospitalization in elderly patients

Machine learning (ML) techniques may improve readmission prediction performance in heart failure (HF) patients. This study aimed to assess the ability of ML algorithms to predict unplanned all-cause 30-day readmissions in HF elderly patients, and to compare them with conventional LACE (Length of hospitalization, Acuity, Comorbidities, Emergency department visits) index. All patients aged ≥ 65 years discharged alive between 2010 and 2019 after a hospitalization for acute HF were included in this retrospective cohort study. We applied MICE (Multivariate Imputation via Chained Equations) method to obtain a balanced, fully valued dataset and LASSO (Least Absolute Shrinkage and Selection Operator) algorithm to get the most significant features. Training (80% of records) and test (20%) cohorts were randomly selected. Study population: 3079 patients, 394 (12.8%) presented at least one readmission within 30 days, and 2685 (87.2%) did not. In the test cohort AUCs (IC95%) of XGBoost, Ada Boost Classifier, Random forest, and Gradient Boosting, and LACE Index were: 0.803 (0.734-0.872), 0.782 (0.711-0.854), 0.776 (0.703-0.848), 0.786 (0.715-0.857), and 0.504 (0.414-0.594), respectively, for predicting readmissions. A SHAP analysis was performed to offer a breakdown of the ML variables associated with readmission. Positive and negative predicting values estimates of the different ML models and LACE index were also provided, for several values of readmission rate prevalence. Among elderly patients, the rate of all-cause unplanned 30-day readmissions after hospitalization due to an acute HF was high. ML models performed better than the conventional LACE index for predicting readmissions. ML models can be proposed as promising tools for the identification of subjects at high risk of hospitalization in this clinical setting, enabling care teams to target interventions for improving overall clinical outcomes.

Reliability of bedside tests for diagnosing peripheral arterial disease in patients prone to medial arterial calcification: A systematic review

BACKGROUND

Medial arterial calcification (MAC), frequently associated with diabetes mellitus (DM) and chronic kidney disease (CKD), is a systemic vascular disorder leading to stiffness and incompressible arteries. These changes impede the accuracy of bedside tests to diagnose peripheral arterial disease (PAD). This review aimed to evaluate the reliability of bedside tests for the detection of PAD in patients prone to MAC.

METHODS

A systematic search (Pubmed, Embase, Web of Science, Cochrane, and Emcare) was performed according to the PRISMA guidelines to identify relevant studies providing data on the performance of bedside tests for the detection of PAD in patients prone to MAC. Studies were included when bedside test were compared to a reference standard. Primary endpoints were the positive and negative likelihood ratios (PLR, NLR). Methodological quality and risk of bias were evaluated using the QUADAS-2 tool.

FINDINGS

In total, 23 studies were included in this review. The most commonly evaluated test was the ankle-brachial index (ABI), followed by toe-brachial index (TBI), toe pressure (TP) measurements, and continuous wave Doppler (CWD). The majority of patients were older, male, and had DM. We found that ABI <0·9 was helpful to diagnose PAD, but failed to rule out PAD (NLR >0·2). The same applied for TP (NLR >0·3) and TBI (5 out of 6 studies revealed an NLR >0·2). CWD (loss of triphasic pattern) is reliable to exclude PAD (NLR 0-0·09), but was only validated in two studies. Overall, methodological quality was poor which led to risk of bias in 20 studies.

INTERPRETATION

The diagnosis of PAD in patients prone to MAC remains challenging. The ABI performed reasonably in the diagnosis of PAD, while the CWD (loss of triphasic signal) can be used to rule out PAD. This systematic review showed that test performances were generally poor with serious concerns in methodological quality of the included studies. We therefore counsel against the use of a single bedside test.

FUNDING

None to declare.

Validation of Two Screening Tools for Anxiety in Hemodialysis Patients

Background: Symptoms of anxiety are often unrecognized and untreated in dialysis patients. We investigated the diagnostic accuracy of two widely used screening tools for anxiety in hemodialysis patients. Methods: For this cross-sectional validation study, chronic hemodialysis patients from eight dialysis centers in the Netherlands were included. The Beck Anxiety Inventory (BAI) and Hospital Anxiety and Depression Scale—Anxiety subscale (HADS-A) were validated by the Mini International Neuropsychiatric Inventory (MINI) diagnostic interview. Receiver operating characteristic curves were used to determine the optimal cut-off values. Results: Of 65 participants, 13 (20%) were diagnosed with one or more anxiety disorders on the MINI, of which 5 were included in the analysis. ROC curves showed a good diagnostic accuracy of the BAI and HADS-A. The optimal cut-off value for the BAI was ≥13 (sensitivity 100%, specificity 85%) and for the HADS-A was ≥10 (sensitivity 80%, specificity 100%). Conclusions: Based on our limited data, both the BAI and the HADS-A seem to be valid screening instruments for anxiety in hemodialysis patients that can be used in routine dialysis care. The HADS-A consists of fewer items and showed fewer false-positive results than the BAI, which might make it more useful in clinical practice.

Development of a clinical prediction rule to identify physical activity after total hip arthroplasty

OBJECTIVE

To develop clinical prediction rule (CPR) of physical activity at 1-year after total hip arthroplasty (THA).

DESIGN

Retrospective cohort study.

SETTING

University hospital with orthopedic surgery.

PARTICIPANTS

The study group included 321 patients (56 men) who underwent primary THA.

INTERVENTION

Not applicable.

MAIN OUTCOMES MEASURES

The data collected included age, body mass index, clinical score from the questionnaires, hip pain, range of motion, muscle strength, and Physical functions (10-Meter Walk Test, Timed Up and Go test and Sit-to-stand). Patients were classified into sufficient and insufficient activity groups based on their University of California, Los Angeles (UCLA) activity score 1 year after THA. Variables measured preoperatively and at 3 weeks postoperatively were analyzed using univariate and multivariate methods to derive CPR for physical activity.

RESULTS

A CPR was developed using the following five factors and cut-offs: age, ≤70.5 years; preoperative UCLA activity score, ≥3.5; preoperative hip abduction strength, ≥0.54 Nm/kg; preoperative knee extension strength, ≥1.04 Nm/kg; and 10-Meter Walk Test, ≤8.49 s at 3 weeks after surgery. The presence of four of the five factors predicted a sufficient physical activity level at 1-year, with a positive likelihood ratio of 5.94 and probability of 85.4%. The presence of five predictor variables increased the probability of sufficient physical activity after THA to 94.7%.

CONCLUSION

This study developed a CPR for physical activity at 1-year after THA. Having four or more of the five measurements were useful indicators for predicting of physical activity at 1 year postoperatively.

Decision-tree derivation and external validation of a new clinical decision rule (DISCERN-FN) to predict the risk of severe infection during febrile neutropenia in children treated for cancer

BACKGROUND

In 2017, international guidelines proposed new management of febrile neutropenia in children with cancer, adapted to the risk of severe infection by clinical decision rules (CDRs). Until now, none of the proposed CDRs has performed well enough in high-income countries for use in clinical practice. Our study aimed to build and validate a new CDR (DISCERN-FN) to predict the risk of severe infection in children with febrile neutropenia.

METHODS

We did two prospective studies. First, a prospective derivation study included all episodes of febrile neutropenia in children (aged <18 years) with a cancer diagnosis and receiving treatment for it who were admitted for an episode of febrile neutropenia, excluding patients already treated with antibiotics for this episode, febrile neutropenia not induced by chemotherapy, those receiving palliative care, and those with a stem cell allograft for less than 1 year, from April 1, 2007, to Dec 31, 2011 from two paediatric cancer centres in France. We collected the children's medical history, and clinical and laboratory data, and analysed their associations with severe infection. Sipina software was used to derive the CDR as a decision tree. Second, a prospective, national, external validation study was done in 23 centres from Jan 1, 2012, to May 31, 2016. The primary outcome was severe infection, defined by bacteraemia, a positive bacterial culture from a usually sterile site, a local infection with a high potential for extension, or an invasive fungal infection. The CDR was applied a posteriori to all episodes to evaluate its sensitivity, specificity, and negative likelihood ratio.

FINDINGS

The derivation set included 539 febrile neutropenia episodes (270 episodes in patients with blood cancer [median age 7·5 years, IQR 3·7-11·2; 158 (59 %) boys and 112 (41%) girls] and 269 in patients with solid tumours [median age 6·6 years, IQR 2·9-14·2; 140 (52 %) boys and 129 (48%) girls]). Significant variables introduced into the decision tree were cancer type (solid tumour vs blood cancer), age, high-risk chemotherapy, level of fever, C-reactive protein concentration (at 24-48 h after admission), and leucocyte and platelet counts and procalcitonin (at admission and at 24-48 h after admission). For the derivation set, the CDR sensitivity was 98% (95% CI 93-100), its specificity 56% (51-61), and the negative likelihood ratio 0·04 (0·01-0·15). 1806 febrile neutropenia episodes were analysed in the validation set (mean age 8·1 years [SD 4·8], 1014 (56%) boys and 792 (44%) girls), of which 332 (18%, 95% CI 17-20) were linked with severe infection. For the validation set, the CDR had a sensitivity of 95% (95% CI 91-97), a specificity of 38% (36-41), and a negative likelihood ratio of 0·13 (0·08-0·21). Our CDR reduced the risk of severe infection to a post-test probability of 0·8% (95% CI 0·2-2·9) in the derivation set and 2·4% (1·5-3·9) in the validation set. The validation study is registered at ClinicalTrials.gov, NCT03434795.

INTERPRETATION

The use of our CDR substantially reduced the risk of severe infection after testing in both the derivation and validation groups, which suggests that this CDR would improve clinical practice enough to be introduced in appropriate settings.

FUNDING

Ligue Nationale Contre le Cancer.

Preoperative magnetic resonance imaging predicts clinicopathological parameters and stages of endometrial carcinomas

BACKGROUND

We investigated the agreement and accuracy of preoperative magnetic resonance imaging (MRI) with postoperative pathological characteristics and stages of endometrial endometrioid carcinoma (EEC).

METHODS

We recruited 527 women with EEC who underwent staging surgery at a single medical institution. The preoperative MRI, stages, and clinical and pathological parameters, including myometrial invasion (MI), cervical invasion (CI), adnexal metastasis (AM), intra-abdominal metastasis, and pelvic and/or para-aortic nodal metastasis, were recorded and analyzed. The agreement and accuracy between the preoperative MRI findings and these parameters and stages were assessed.

RESULTS

The rate of the preoperative MRI-based clinical stage matching the postoperative surgical stage was 85.2% in International Federation of Gynecology and Obstetrics stage IA, 51.9% in stage IB, 35.5% in stage II, 5.3% in stage IIIA, 33.3% in stage IIIB, 28.6% in stage IIIC1, 64.3% in stage IIIC2, and 93.8% in stage IVB. The consistency between radiologists and pathologists was 80.5% for deep MI, 91.5% for cervical invasion, 92.2% for adnexal metastasis, 98.9% for intra-abdominal metastasis, and 87.5% and 92.2% for pelvic and para-aortic nodal metastases, respectively. The negative predictive value of intra-abdominal metastasis was the highest with 99.8%.

CONCLUSIONS

Preoperative MRI could be an excellent tool for routine preoperative assessment to predict pathological parameters and stages of EEC, especially in excluding intra-abdominal metastatic disease.

Diagnostic validity, accuracy and inter-rater reliability of a phonological assessment for Danish-speaking children

PURPOSE

The identification and differential diagnosis of children with speech sound disorders (SSD) is an important task of paediatric speech-language pathologists (SLPs). A correct identification requires valid and reliable assessment tools. Therefore, the aim of the present study was to investigate the diagnostic validity and accuracy as well as inter-rater reliability of the phonology test of LogoFova which was developed for Danish-speaking children.

METHOD

Investigation was carried out on two Danish-speaking populations: 61 suspected typically developing (TD) children and 61 children with suspected speech sound disorder aged 2-6 years. All children were assessed with the single-word picture-naming test of LogoFoVa. In order to determine diagnostic validity, it was investigated whether the test differentiated TD children from children with SSD as well as subgroups of SSD via a phonetic and phonological pattern analysis. Two different cut-off criteria were applied for the definition of patterns. Sensitivity and specificity as well as likelihood ratios were additionally calculated. To determine inter-rater reliability, transcriptions, pattern analyses and subgrouping were compared across raters.

RESULTS

Overall, diagnostic validity of the picture-naming test of LogoFoVa was good as differentiation between TD children and children with suspected SSD as well as amongst subgroups of SSD (articulation impairment, phonological delay and atypical speech development) was possible. However, accuracy of differentiation between TD children and children with SSD was affected by the cut-off criterion applied. Inter-rater reliability was found to be almost perfect for transcription and moderate for identification of phonological processes as well as for subgrouping. Again, agreement rates depended on the cut-off criterion chosen for the definition of a phonological pattern.

CONCLUSION

LogoFoVa was found to be a reliable and valid clinical tool for the identification and subgrouping of children with SSD in Danish SLP practice if a new cut-off criterion was applied.

Performance of lymph node cytopathology in diagnosis and characterization of lymphoma in dogs

BACKGROUND

Cytopathology is a minimally invasive and convenient diagnostic procedure, often used as a substitute for histopathology to diagnose and characterize lymphoma in dogs.

OBJECTIVES

Assess the diagnostic performance of cytopathology in diagnosing lymphoma and its histopathological subtypes in dogs.

ANIMALS

One-hundred and sixty-one lymph node samples from 139 dogs with enlarged peripheral lymph nodes.

METHODS

Based only on cytopathology, 6 examiners independently provided the following interpretations on each sample: (a) lymphoma vs nonlymphoma; (b) grade and phenotype; and (c) World Health Organization (WHO) histopathological subtype. Histopathology and immunohistochemistry (IHC) findings were used as reference standards to evaluate diagnostic performance of cytopathology. Clinical, clinicopathologic, and imaging data also were considered in the definitive diagnosis.

RESULTS

Classification accuracy for lymphoma consistently was >80% for all examiners, whereas it was >60% for low grade T-cell lymphomas, >30% for high grade B-cell lymphomas, >20% for high grade T-cell lymphomas, and <40% for low grade B-cell lymphomas. Interobserver agreement evaluated by kappa scores was 0.55 and 0.32 for identification of lymphoma cases, and of grade plus immunophenotype, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Cytopathology may result in accurate diagnosis of lymphoma, but accuracy decreases when further characterization is needed. Cytopathology represents a fundamental aid in identifying lymphoma and can be used as a screening test to predict grade and phenotype. However, these results must be confirmed using other ancillary techniques, including flow cytometry, histopathology, and immunohistochemistry (IHC).

Accuracy of diagnostic clinical tests and questionnaires in screening for carpal tunnel syndrome among workers- A systematic review

OBJECTIVE

To synthesize and appraise the evidence on the diagnostic accuracy of the clinical examination tests and questionnaires for screening carpal tunnel syndrome (CTS) among workers.

DESIGN

Systematic review of diagnostic test accuracy METHODS: Electronic search of 3 online databases (CINAHL, Embase, Medline) was done on August 31, 2020. Studies reporting the diagnostic accuracy of clinical examination tests in workers, compared to a reference standard test, were included. Diagnostic accuracy measures such as sensitivity (Sn) and specificity (Sp) were extracted and reported for different clinical examination tests. The risk of bias and applicability concerns were rated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool by 2 independent reviewers. Diagnostic tests accuracy extension of the PRISMA guidelines were followed.

RESULTS

Twelve studies reporting on the diagnostic accuracy of the clinical examination tests for workers suspected of CTS were included. Fourteen different clinical examination tests were evaluated in the studies, including sensorimotor, provocative maneuvers, questionnaires, and hand symptom diagrams (HSD). Ten of the included studies had an either unclear or high risk of bias. The most accurate tests to diagnose CTS in workers were the Katz HSD (with Sn ranging from 38%-93%, and Sp ranging from 25%-89%) and Kamath and Stothard questionnaire (Sn and Sp = 100%). Combination of Katz HSD with either the Phalen's maneuver or the Tinel's sign resulted in excellent Sp (83% and 89%, respectively).

CONCLUSIONS

Low to moderate quality evidence indicates variability in individual clinical examination tests used to screen for CTS in workers. Diagnostic self-report tools consisting of hand diagrams and/or diagnostic questions provide low burden and high accuracy. Still, they require more rigorous investigation about their value alone or in combination with clinical assessment tests.

Creatine kinase test diagnostic accuracy in neonatal screening for Duchenne Muscular Dystrophy: A systematic review

OBJECTIVES

to evaluate the accuracy of the creatine kinase test in neonatal screening for Duchenne Muscular Dystrophy.

METHODS

Investigations were carried out in six databases, gray literature and manual search. All studies and data extraction eligibility processes were carried out in paired mode. The methodological stringency of the studies was assessed using the modified QUADAS 2 tool. The performance measures of the test were calculated using the Meta-DiSc software, version 1.4.

RESULTS

11 studies were included, with a total sample of 1,416,123 newborns. The positive likelihood ratio was more than 10 in these studies. On the other hand, the negative likelihood ratio was up to 0.2 in 9/10 studies; however, when considering the upper limit of the confidence interval, only 4/10 studies showed a negative likelihood ratio less than 0.2 and in 6/11 it was greater than 0.5. Specificity was close to 1 in studies. The sensitivity was equal to or greater than 0.81 in 10/11 studies; however, when considering the reliability's minimum interval limit, only 6/10 studies showed sensitivity equal to or greater than 0.7. Ten studies were summarized on a ROC curve indicating good performance (Area under the curve = 0.9980 and Q index = 0.9846).

CONCLUSIONS

the creatine kinase test showed good accuracy in screening for cases of Duchenne Muscular Dystrophy and may be a useful alternative in the early diagnosis of the disease followed by confirmatory genetic testing.

A narrative review of frailty assessment in older patients at the emergency department

Optimizing emergency care for the aging population is an important future challenge, as the proportion of older patients at the emergency department (ED) rapidly increases. Older patients, particularly those who are frail, have a high risk of adverse outcomes after an ED visit, such as functional decline, institutionalization, and death. The ED can have a key position in identifying frail older patients who benefit most from comprehensive geriatric care [including delirium preventive measures, early evaluation of after-discharge care, and a comprehensive geriatric assessment (CGA)]. However, performing extensive frailty assessment is not suitable at the ED. Therefore, quick and easy-to-use instruments are needed to identify older patients at risk for adverse outcomes. This narrative review outlines the importance and complexity of frailty assessment at the ED. It aligns the available screening instruments, including clinical judgment as frailty assessment, and summarizes arguments for and against frailty assessment at the ED.

Application of udder surface temperature by infrared thermography for diagnosis of subclinical mastitis in Holstein cows located in tropical highlands

Several reports have indicated that udder surface temperature (UST) can be a useful indicator of subclinical mastitis (SCM). The objective was to evaluate UST by infrared thermography (IRT) as a diagnostic tool for SCM and intramammary infection (IMI), and to assess the influence of environmental conditions in the potential diagnosis of this disease in dairy cows located at high-altitude tropical regions. A total of 105 cows (397 quarters) from 3 dairy farms with mechanical and manual milking methods were enrolled in the study. Subclinical mastitis was diagnosed when quarter samples had a somatic cell count (SCC) ≥200 × 10³ cells/mL, microbial growth (MG) was defined when a major pathogen (≥1 cfu/plate) or Corynebacterium spp. (≥10 cfu/plate) was isolated, and IMI was defined as the presence of MG and SCC ≥100 × 10³ cells/mL. Infrared images were taken with a thermal camera placed 1 m away from the udder, and shots of the rear and left and right lateral view were made during the morning milking, before any manipulation of the udder and employing dark cardboard on the contralateral side to avoid artifacts in the background. A multilevel mixed effects linear regression model clustered within cows and herd was performed to evaluate the associations with UST. Clinical performance was evaluated using the Youden index to establish the optimum UST thresholds, which were set at 32.6°C for any case definition when milking was by hand, at 33.7°C for MG, and at 34°C for SCM and IMI in machine-milked quarters. Sensitivity (Se), specificity (Sp), area under curve (AUC), and positive likelihood ratio (+LR) were also assessed. Test agreement was assessed by kappa coefficient (κ). The UST of healthy quarters ranged between (95% CI) 32.4 and 32.6°C, lower than SCM quarters (n = 88) at 32.9°C (95% CI: 32.7-33.1 °C), MG quarters (n = 56) at 33.5°C (95% CI: 33.3-33.7°C), and IMI quarters (n = 50) at 33.5°C (95% CI: 33.2-33.7 °C). The UST was also related to the milking method: higher temperatures were observed for hand milking (n = 90) compared with machine milking (n = 185). No relation between environmental conditions such as wind speed, atmospheric temperature, relative humidity, and temperature-humidity index and UST were observed during this study. For hand milking, the optimal UST threshold was 32.6°C; for SCM, Se = 0.53, Sp = 0.89, AUC = 0.71, κ = 0.4; for MG, Se = 0.83, Sp = 0.93, AUC = 0.88, κ = 0.77; and for IMI, Se = 0.82, Sp = 0.92, AUC = 0.87, κ = 0.74. The machine milking threshold for SCM resulted in Se = 0.42, Sp = 0.97, AUC = 0.70, κ = 0.47; for MG, Se = 0.82, Sp = 0.89, AUC = 0.85, κ = 0.60; and for IMI, Se = 0.82, Sp = 0.98, AUC = 0.90, κ = 0.79. These findings suggest that UST determined by IRT is higher in machine-milked cows and in quarters with MG and IMI than in healthy quarters; therefore, UST by IRT is a reliable, clinically useful method for MG and IMI diagnosis.

Refinement and validation of a tool for stratifying patients with musculoskeletal pain

BACKGROUND

Patients with musculoskeletal pain in different body sites share common prognostic factors. Using prognosis to stratify and treatment match can be clinically and cost-effective. We aimed to refine and validate the Keele STarT MSK Tool for prognostic stratification of musculoskeletal pain patients.

METHODS

Tool refinement and validity was tested in a prospective cohort study, and external validity examined in a pilot cluster randomized controlled trial (RCT). Study population comprised 2,414 adults visiting U.K. primary care with back, neck, knee, shoulder or multisite pain returning postal questionnaires (cohort: 1,890 [40% response]; trial: 524). Cohort baseline questionnaires included a draft tool plus refinement items. Trial baseline questionnaires included the Keele STarT MSK Tool. Physical health (SF-36 Physical Component Score [PCS]) and pain intensity were assessed at 2- and 6-month cohort follow-up; pain intensity was measured at 6-month trial follow-up.

RESULTS

The tool was refined by replacing (3), adding (3) and removing (2) items, resulting in a 10-item tool. Model fit (R² ) was 0.422 and 0.430 and discrimination (c statistic) 0.839 and 0.822 for predicting 6-month cohort PCS and pain (respectively). The tool classified 24.9% of cohort participants at low, 41.7% medium and 33.4% high risk, clearly discriminating between subgroups. The tool demonstrated model fit of 0.224 and discrimination 0.73 in trial participants. Multiple imputation confirmed robustness of findings.

CONCLUSIONS

The Keele STarT MSK Tool demonstrates good validity and acceptable predictive performance and clearly identifies groups of musculoskeletal pain patients with different characteristics and prognosis. Using prognostic information for stratification and treatment matching may be clinically/cost-effective.

SIGNIFICANCE

The paper presents the first musculoskeletal pain prognostic stratification tool specifically for use among all primary care patients with the five most common musculoskeletal pain presentations (back, neck, knee, shoulder or multisite pain). The Keele STarT MSK Tool identifies groups of musculoskeletal pain patients with clearly different characteristics and prognosis. Using this tool for stratification and treatment matching may be clinically and cost-effective.

Validation of the Delirium Diagnostic Tool-Provisional (DDT-Pro) With Medical Inpatients and Comparison With the Confusion Assessment Method Algorithm

OBJECTIVE

Delirium remains underdetected as a result of its broad constellation of symptoms and the inadequate neuropsychiatric expertise of most medical-surgical clinicians. Brief, accurate tools are needed to enhance detection.

METHODS

The authors extended validation of the Delirium Diagnostic Tool-Provisional (DDT-Pro), originally validated in a study of inpatients with traumatic brain injury for diagnosis of delirium by nonexpert clinicians, for 200 general medical inpatients in Colombia. The three structured, quantitatively rated items in DDT-Pro represent the three core delirium domains.

RESULTS

High interrater reliability between physician and nurse (0.873) administrators, internal consistency (>0.81), and content validity were found. Compared with independent reference standard diagnosis with DSM-5 or the Delirium Rating Scale-Revised-98, the area under the receiver operating characteristic (ROC) curve (global diagnostic accuracy) range was 93.8%-96.3%. ROC analysis revealed the same cutoff score (≤6) as that for the original study, with somewhat lower sensitivities of 88.0%-90.0% and specificities of 85.3%-81.2% (independent expert physician or nurse ratings). Even when rated by a trained expert physician, the original version of the Confusion Assessment Method algorithm (CAM-A) performed moderately, with lower sensitivities (61.8%-70.0%) than the DDT-Pro (88.0%-100%) and somewhat higher specificities (84.8%-95.3% versus 67.4%-86.7%), with values depending on dementia status, reference standard, and rater type. Accuracies for the DDT-Pro and CAM-A were comparable (DDT-Pro: 83.0%-87.5% versus CAM-A: 87.5%-88.5%), although lower in the dementia subgroup, especially for CAM-A. However, these tools were significantly discordant, especially in negative cases, which suggests that they do not detect diagnosis of patients in the same way.

CONCLUSIONS

The DDT-Pro had high validity and reliability in provisional delirium diagnosis by physicians and nonexpert clinicians, although further validation is warranted before widespread use can be recommended.

A new application of the Rotterdam Diabetic Foot Study Test Battery: grading pedal sensory loss to predict the risk of foot ulceration

AIMS

To assess the relationship between the degree of loss of foot sensation at baseline and incidence of foot ulceration (DFU).

METHODS

Diabetic patients (n = 416) participating in the observational Rotterdam Diabetic Foot (RDF) Study were followed prospectively (median 955.5 days (IQR, 841.5-1121)). Subjects underwent sensory testing of the feet (39-item RDF Study Test Battery) at baseline and were assessed regarding incident DFU. Seven groups of incremental degree of sensory loss were distinguished, according to the RDF-39 sum score. Kaplan-Meier and regression analyses were used to determine the independent hazard of baseline variables for new DFU.

RESULTS

40 participants developed DFUs. The mean incident rate of new-onset ulceration from study start was 4.5 (95%CI: 3.3 to 6.1) per 100 person-years, which increased significantly from 0 to 67.70 in the seven groups (p < 0.0005). Predictors for DFUs were higher RDF-39 score (aHR: 1.173, p < 0.0005) and kidney function (aHR: 1.022, p = 0.016). Prior DFU suggests increased mortality risk.

CONCLUSIONS

The degree of sensory loss at baseline was associated with progression to DFU during follow-up. Grading the loss of sensation using the RDF Study Test Battery may result in a more precise risk stratification compared to the use of the 10 g monofilament according to current guidelines.

Rescuing monopronucleated-derived human blastocysts: a model to study chromosomal topography and fingerprinting

OBJECTIVE

To quantify the percentage of monopronuclear-derived blastocysts (MNBs) that are potentially useful for reproductive purposes using classic and state-of-the-art chromosome analysis approaches, and to study chromosomal distribution in the inner cell mass (ICM) and trophectoderm (TE) for intertissue/intratissue concordance comparison.

DESIGN

Prospective experimental study.

SETTING

Single-center in vitro fertilization clinic and reproductive genetics laboratory.

PATIENT(S)

A total of 1,128 monopronuclear zygotes were obtained between June 2016 and December 2018.

INTERVENTION(S)

MNBs were whole-fixed or biopsied to obtain a portion of ICM and 2 TE portions (TE1 and TE2) and were subsequently analyzed by fluorescence in situ hybridization, new whole-genome sequencing, and fingerprinting by single-nucleotide polymorphism array-based techniques (a-SNP).

MAIN OUTCOME MEASURE(S)

We assessed MNB rate, ploidy rate, and chromosomal constitution by new whole-genome sequencing, and parental composition by comparative a-SNP, performed in a "trio"-format (embryo/parents). The 24-chromosome distribution was compared between the TE and the ICM and within the TE.

RESULT(S)

A total of 18.4% of monopronuclear zygotes progressed to blastocysts; 77.6% of MNBs were diploid; 20% of MNBs were male and euploid, which might be reproductively useful. Seventy-five percent of MNBs were biparental and half of them were euploid, indicating that 40% might be reproductively useful. Intratissue concordance (TE1/TE2) was established for 93.3% and 73.3% for chromosome matching. Intertissue concordance (TE/ICM) was established for 78.8%, but 57.6% for chromosome matching. When segmental aneuploidy was not considered, intratissue concordance and chromosome matching increased to 100% and 80%, respectively, and intertissue concordance and chromosome matching increased to 84.8% and 75.8%, respectively.

CONCLUSION(S)

The a-SNP-trio strategy provides information about ploidy, euploidy, and parental origin in a single biopsy. This approach enabled us to identify 40% of MNBs with reproductive potential, which can have a significant effect in the clinical setting. Additionally, segmental aneuploidy is relevant for mismatched preimplantation genetic testing of aneuploidies, both within and between MNB tissues. Repeat biopsy might clarify whether segmental aneuploidy is a prone genetic character.

To map or not to map the cN0 neck: Impact of sentinel lymph node biopsy in canine head and neck tumours

Tumour stage is a prognostic indicator for canine malignant head and neck tumours (MHNT). However, consensus is lacking on nodal staging in the absence of clinically apparent nodal disease (cN0 neck). This prospective observational study aims to determine the diagnostic accuracy of radiopharmaceutical and blue dye for sentinel lymph node biopsy (SLNB), to assess the correspondence between sentinel lymph node (SLN) and clinically expected regional lymph node (RLN) and the impact on staging of the procedure in dogs with MHNT and cN0 neck. Twenty-three dogs with MHNT and cN0 neck underwent tumour excision and SLNB guided by preoperative lymphoscintigraphy and intraoperative gamma-probe and blue dye. Diagnostic performances and detection rate were calculated. Correspondence between SLN and RLN, number of nodes excised, histopathological status of the SLN and complications related to the procedure were recorded. The mapping technique identified at least one SLN in 19/23 dogs, with a detection rate of 83%. The SLN did not correspond to the RLN in 52% of dogs. Multiple nodes were removed in 61% of dogs. At histopathology, eight (42%) dogs had SLN+, of which four differed from the RLN. Only minor self-limiting complications occurred in five (22%) dogs. Radiopharmaceutical and blue dye guidance is accurate (sensitivity 88.9%; specificity 100%) for SLNB in dogs with MHNT and cN0 and allowed the extirpation of unpredictable and/or multiple SLN with minimal morbidity. Incorporation of SLNB in the management of MHNT is desirable to correctly stage the cN0 neck, owing the unpredictability of the lymphatic drainage.

Pruebas diagnósticas: Razones de probabilidad

La utilidad de una prueba diagnóstica se cuantifica mediante el cálculo de dos medidas: Medidas de probabilidad. Medidas de razones de probabilidad. Las medidas de probabilidad son la sensibilidad, la especificidad, valor predictivo positivo y el valor predictivo negativo. La sensibilidad y la especificidad de una prueba diagnóstica se usan para escoger la mejor prueba a utilizar, entre varias pruebas diagnósticas disponibles; sin embargo, estas dos medidas no pueden ser utilizadas para estimar la probabilidad de determinada enfermedad en un paciente en particular. En la práctica clínica usual, es esencial saber cuál es la probabilidad que un paciente con un resultado positivo en una prueba diagnóstica presente la enfermedad; y cuál es la probabilidad que un paciente con un resultado negativo en una prueba diagnóstica no presente la enfermedad. Los valores predictivos positivos y negativos nos brindan la respuesta a esta cuestión. Sin embargo, los valores predictivos positivo y negativo dependen tanto de la sensibilidad y especificidad así como de la prevalencia de la enfermedad en la muestra del estudio. Las medidas de razones de probabilidad son la segunda forma de describir el rendimiento o utilidad de una prueba diagnóstica. Las razones de probabilidad poseen dos propiedades importantes: Resumen el mismo tipo de información que la sensibilidad y la especificidad. Pueden utilizarse para calcular la probabilidad de la enfermedad después de una prueba positiva o negativa. El propósito de esta publicación es definir el definir el concepto de razones de probabilidad, describir sus principales fortalezas y explicar cómo se calculan las razones de probabilidad cuando la prueba de interés expresa sus resultados en forma dicotómica (positivo / negativo), en más de dos categorías o de forma ordinal.

Diagnostic Accuracy with Total Adenosine Deaminase as a Biomarker for Discriminating Pleural Transudates and Exudates in a Population-Based Cohort Study

Background

An initial step in the evaluation of patients with pleural effusion syndrome (PES) is to determine whether the pleural fluid is a transudate or an exudate.

Objectives

To investigate total adenosine deaminase (ADA) as a biomarker to classify pleural transudates and exudates.

Methods

An assay of total ADA in pleural fluids (P-ADA) was observed using a commercial kit in a population-based cohort study.

Results

157 pleural fluid samples were collected from untreated individuals with PES due to several causes. The cause most prevalent in transudate samples (21%, n = 33/157) was congestive heart failure (79%, 26/33) and that among exudate samples (71%, n = 124/157) was tuberculosis (28.0%, 44/124). There was no significant difference in the proportion of either sex between the transudate and exudate groups. The median values of P-ADA were significantly different (P < 0.0001) between both total exudates (18.4 U/L; IQR, 9.85-41.4) and exudates without pleural tuberculosis (11.0 U/L; IQR, 7.25-19.75) and transudates (6.85; IQR, 2.67-11.26). For exudates, the AUC was 0.820 (95% CI, 0.751-0.877; P < 0.001), with excellent discrimination. The optimum cut-off point in the ROC curve was determined as the level that provided the maximum positive likelihood ratio (PLR; 14.64; 95% CI, 2.11-101.9) and was22.0 U/L. For transudates, the AUC was 0.8245 (95% CI, 0.7470-0.9020; P < 0.0001). Internal validation of the AUC after 1000 resamples was evaluated with a tolerance minor than 2%. The clinical utility was equal to 92% (95% CI, 0.84 to 0.96, P < 0.05).

Conclusions

P-ADA is a useful biomarker for distinguishing pleural exudates from transudates.

Diagnostic Concordance between Random Upper Arm Circumference and Mid Upper Arm Circumference Measurements among Children Aged 6-59 Months in South Ethiopia: A Community-Based Cross-Sectional Study

Random upper arm circumference (RUAC) is frequently used for malnutrition screening among children aged 6-59 months. However, inadequate evidence exists regarding its agreement with mid upper arm circumference (MUAC). This study examined diagnostic concordance between RUAC and standard MUAC measurements and tested RUAC's ability for screening malnutrition among children aged 6-59 months. A cross-sectional study was conducted from April 30 to May 30/2015 in Ethiopia. Data were taken from a sample of 819 children aged 6-59 months with a simple random sampling technique. The data were analyzed using SPSS version 22 software. The kappa agreement level, sensitivity, and specificity were calculated. The receiver operating curve was prepared to determine the optimal cutoff RUAC for the sensitivity and specificity. With National Center for Health Statistics (NCHS) cutoff (12 cm), the performance of RUAC measurements in terms of sensitivity was low (44%). The kappa agreement level between the two measurements was 0.551 (p value < 0.001). With the new WHO cutoff (12.5 cm), however, RUAC was improved in validity (sensitivity 81%), specificity 96.9%, and kappa agreement level (K = 0.807; p < 0.001).

Trends in Geriatric Emergency Medicine

Geriatric emergency medicine has emerged as a subspecialty of emergency medicine over the past 25 years. This emergence has seen the development of increases in training opportunities, care delivery strategies, collaborative best practice guidelines, and formal geriatric emergency department accreditation. This multidisciplinary field remains ripe for continued development in the coming decades as the aging US population parallels a call from patients, health care providers, and health systems to improve the delivery of high-value care. This article educates emergency medicine practitioners and highlights high-value care practice trends to inform and prioritize decision-making for this unique patient population.

Interval colonoscopy following acute diverticulitis should not be discouraged yet: results from a retrospective cohort

BACKGROUND

Although included in some guidelines, the recommendation of interval colonoscopy after an acute diverticulitis (AD) episode has recently been questioned. In this study, we evaluated the incidence of colon cancer during the follow-up of an episode of AD.

METHODS

A retrospective review was carried out of patients with conservatively treated AD at our Institution (January 2011 to December 2018) with or without endoscopic study. Patients who had no colonoscopy performed were followed for two years. The demographic, clinical, radiological, follow-up and anatomopathological records were analysed. We determined CT scan validity for the differential diagnosis of CC and AD; sensibility, specificity, predictive values and likelihood ratios were calculated. Patients lost to follow-up and patients who had had colonoscopy in the previous three years were excluded.

RESULTS

This study included 285 patients with a mean age of 59 years. A total of 225 interval colonoscopies were performed and 60 patients without colonoscopy were followed up. There were 19 CC (6.7%) diagnosed, 14 with interval colonoscopy and 5 during follow-up; 8 (42.1%) happened in patients who had had an episode of uncomplicated AD. Although CT scan accuracy is high, 87.7%, positive and negative likelihood ratios were low, 4.67 and 0.64, respectively.

CONCLUSIONS

Interval colonoscopy should still be advisable after an episode of AD. The rationale for this statement is based on a non-negligible rate of hidden CC and an important uncertainty in the differential diagnosis.

Evaluation of 3 refractometers to determine transfer of passive immunity in neonatal beef calves

Background

Refractometry is used to assess transfer of passive immunity (TPI), but studies evaluating different refractometers and appropriate thresholds for recommended target immunoglobulin G (IgG) concentrations for beef calves are limited.

Objectives

To evaluate test performance of digital (DSTP) and optical (OSTP) serum total protein (STP) refractometers and a digital Brix (DBRIX) refractometer for assessment of passive immunity in beef calves.

Animals

A total of 398 beef calves from 6 herds, 1 to 7 days of age.

Methods

Serum IgG concentration was estimated by DSTP, OSTP, and DBRIX, and measured by radial immunodiffusion (RID). Correlation coefficients (r) among results were calculated. Optimal STP and Brix thresholds for identification of IgG <10, <16, and <24 g/L were determined using interval likelihood ratios. Refractometer performance and agreement were assessed using areas under the curve (AUC), diagnostic test characteristics, Cohen's kappa (κ), and Bland‐Altman analysis.

Results

Refractometer results were highly correlated with RID (r = 0.82‐0.91) and with each other (r = 0.91‐0.95), and overall test performance was excellent (AUC = 0.93‐0.99). The STP concentrations of ≤5.1, ≤5.1, and ≤5.7 g/dL and Brix percentages of ≤7.9%, ≤8.3%, and ≤8.7% indicated IgG concentrations <10, <16, and <24 g/L, respectively. Agreement of refractometers with RID was variable (κ = 0.46‐0.80) and among refractometers was substantial (κ = 0.62‐0.89).

Conclusions and Clinical Importance

All refractometers showed good utility as monitoring tools for assessment of TPI in beef calves.

Impact of the beta-lacta test on the management of urinary tract infections at the emergency department

INTRODUCTION

Rapid detection of extended-spectrum β-lactamases is essential. In this study, we evaluated the potential impact of β-lacta test on both the times to appropriate antibiotic therapy and to the implementation of patient isolation measures.

PATIENTS AND METHODS

We included prospectively all the patients admitted to the emergency department for clinical suspicion of urinary tract infection. Compared with physician's decision, we analysed the potential impact of β-lacta test on the initial antibiotic therapy and on the implementation of hygiene measures. This study has been registered under number NCT02897609.

RESULTS

We included 203 patients, 43% with acute pyelonephritis and 21% with acute prostatitis. The β-lacta test had a 95.2% sensitivity and a 99.5% specificity to detect extended-spectrum β-lactamases. Taking the β-lacta test results into account would have decreased significantly both the times to appropriate therapy and to isolation measures from 54 to 2.7 h and from 55.2 to 2.6 h, respectively.

CONCLUSION

The β-lacta test could reduce significantly the times to appropriate therapy and implementation of isolations measures.

Validity of the self-reported five-part questionnaire as an assessment of generalized joint hypermobility in early pregnancy

Background

The assessment of generalized joint hypermobility is difficult due to differences in classification methods and in the performance of joint mobility assessment. The primary aim was to evaluate the validity of the self-reported five-part questionnaire, 5PQ, for identifying generalized joint hypermobility using the Beighton score as reference test. The secondary aim was to describe how joint angles measured in degrees included in the Beighton score varied in different cut-off levels in the self-reported 5PQ and the Beighton score.

Methods

A cross-sectional validity study with a total of 301 women in early pregnancy, mean age of 31 years, were included in the study. The participants answered the self-reported 5PQ before the joint angles were measured. To standardize the joint mobility measurement, a structural protocol was used. The sensitivity, specificity, receiver operating characteristic curve, area under curve, positive- and negative predictive value, positive likelihood ratio and Spearman’s rank correlation between the self-reported 5PQ ≥ 2 and the Beighton score ≥ 5 were used as main outcome measures in the validity analyses. Joint angles, measured in degrees, were calculated with means in relation to different cut-off levels.

Results

There was moderate correlation between the self-reported 5PQ and the Beighton score. The highest combined sensitivity, 84.1%, as well as specificity, 61.9%, was on 5PQ cut-off level ≥ 2, with a 38% false-positive rate, a moderate area under curve, a low positive predictive value and likelihood ratio, and a high negative predictive value. The odds of a self-reported 5PQ, cut-off level ≥ 2, among women with generalized joint hypermobility, Beighton ≥5, was low indicating a low post-test probability. The mean for all joint angles measured in degrees increased with increased cut-off levels, both in the Beighton score and in the self-reported 5PQ. However, there was a significant variation for each cut-off level.

Conclusions

There is uncertainty in identifying generalized joint hypermobility in young women using the self-reported 5PQ with a cut-off level of ≥2 when the Beighton score ≥ 5 is used as the reference test. The strength of the self-reported 5PQ is to rule-out women without generalized joint hypermobility.

Diagnosing COVID-19 in the Emergency Department: A Scoping Review of Clinical Examinations, Laboratory Tests, Imaging Accuracy, and Biases

OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged as a global pandemic in early 2020 with rapidly evolving approaches to diagnosing the clinical illness called coronavirus disease (COVID-19). The primary objective of this scoping review is to synthesize current research of the diagnostic accuracy of history, physical examination, routine laboratory tests, real-time reverse transcription-polymerase chain reaction (rRT-PCR), immunology tests, and computed tomography (CT) for the emergency department (ED) diagnosis of COVID-19. Secondary objectives included a synopsis of diagnostic biases likely with current COVID-19 research as well as corresponding implications of false-negative and false-positive results for clinicians and investigators.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Scoping Review (PRISMA-ScR)-adherent synthesis of COVID-19 diagnostic accuracy through May 5, 2020, was conducted. The search strategy was designed by a medical librarian and included studies indexed by PubMed and Embase since January 2020.

RESULTS

A total of 1,907 citations were screened for relevance. Patients without COVID-19 are rarely reported, so specificity and likelihood ratios were generally unavailable. Fever is the most common finding, while hyposmia and hypogeusia appear useful to rule in COVID-19. Cough is not consistently present. Lymphopenia is the mostly commonly reported laboratory abnormality and occurs in over 50% of COVID-19 patients. rRT-PCR is currently considered the COVID-19 criterion standard for most diagnostic studies, but a single test sensitivity ranges from 60% to 78%. Multiple reasons for false-negatives rRT-PCR exist, including sample site tested and disease stage during which sample was obtained. CT may increase COVID-19 sensitivity in conjunction with rRT-PCR, but guidelines for imaging patients most likely to benefit are emerging. IgM and IgG serology levels are undetectable in the first week of COVID-19, but sensitivity (range = 82% to 100%) and specificity (range = 87% to 100%) are promising. Whether detectable COVID-19 antibodies correspond to immunity remains unanswered. Current studies do not adhere to accepted diagnostic accuracy reporting standards and likely report significantly biased results if the same tests were to be applied to general ED populations with suspected COVID-19.

CONCLUSIONS

With the exception of fever and disorders of smell/taste, history and physical examination findings are unhelpful to distinguish COVID-19 from other infectious conditions that mimic SARS-CoV-2 like influenza. Routine laboratory tests are also nondiagnostic, although lymphopenia is a common finding and other abnormalities may predict severe disease. Although rRT-PCR is the current criterion standard, more inclusive consensus-based criteria will likely emerge because of the high false-negative rate of PCR tests. The role of serology and CT in ED assessments remains undefined.

Atypical Endometrial Hyperplasia and Unexpected Cancers at Final Histology: A Study on Endometrial Sampling Methods and Risk Factors

Background: Up to 40% of women with atypical endometrial hyperplasia (AEH) can reveal endometrial cancer (EC) at hysterectomy. The pre-operative endometrial sampling method (ESM) and some independent cancer predictors may affect this outcome. The present study aimed to compare the rate of EC at hysterectomy in women with AEH undergoing dilation and curettage (D&C), hysteroscopically-guided biopsy (HSC-bio), or hysteroscopic endometrial resection (HSC-res). The secondary outcome was to compare the reliability of ESMs in women showing independent variables associated with EC. Methods: Two-hundred-and-eight consecutive women with AEH and undergoing hysterectomy between January 2000 and December 2017 were analyzed retrospectively. Based on pre- and post-test probability analysis for EC, three ESMs were compared: D&C, HSC-bio, and HSC-res. Univariate and multivariate analyses were performed to assess risk factors predicting cancer on final histology. Finally, the patient’s characteristics were compared between the three ESM groups. Results: D&C and HSC-bio included 75 women in each group, while HSC-res included 58 women. Forty-nine women (23.6%) revealed cancer at hysterectomy (pre-test probability). Post-test probability analysis showed that HSC-res had the lowest percentage of EC underestimation: HSC-res = 11.6%; HSC-bio = 19.5%; D&C = 35.3%. Patient characteristics showed no significant differences between the three ESMs. Multivariate analysis showed that body mass index ≥40 (Odds Ratio (OR) = 19.75; Confidence Intervals (CI) 2.193–177.829), and age (criterion > 60 years) (OR = 1.055, CI 1.002–1.111) associated significantly with EC. In women with one or both risk factors, post-test probability analysis showed that HSC-res was the only method with a lower EC rate at hysterectomy compared to a pre-test probability of 44.2%: HSC-res = 19.96%; HSC-bio = 53.81%; D&C = 63.12%. Conclusions: HSC-res provided the lowest rate of EC underestimation in AEH, also in women showing EC predictors. These data may be considered for better diagnostic and therapeutic planning of AEH.

Is peak expiratory flow an accurate sarcopenia screening tool in older patients referred to respiratory rehabilitation?

PURPOSE

To assess the performance of peak expiratory flow (PEF) for sarcopenia screening in patients with chronic obstructive pulmonary disease (COPD), using the revised European Working Group on Sarcopenia in Older People (EWGSOP-2) criteria as the reference standard in pulmonary rehabilitation patients; and second, to study the factors associated with low PEF in this population.

METHODS

Diagnostic accuracy study conducted in consecutive community-dwelling COPD rehabilitation patients. Sensitivity, specificity, accuracy, likelihood ratios, predictive values, and area under the Receiver-Operating Characteristic curve were retrospectively calculated for PEF (index test) and compared with EWGSOP-2 criteria (reference standard).

RESULTS

Of 151 potentially eligible patients, 79 (67.5 ± 7.1 years; 78.8% men) fulfilled inclusion criteria and 10 (12.7%) had a diagnosis of sarcopenia. The PEF cut-off with highest accuracy (65.8%) was PEF ≤ 200 L/min (sensitivity 90%, specificity 62.3%, and positive and negative likelihood ratios 2.39 and 0.16, respectively). Airway obstruction and muscle mass were significantly associated with PEF ≤ 200 L/min.

CONCLUSIONS

Considering the EWGSOP-2 criteria as the reference standard, a cut-off of PEF ≤ 200 L/min showed only fair validity for detecting sarcopenia, so it cannot be recommended as a stand-alone screening tool in older rehabilitation patients with COPD.

Effectiveness of bedside investigations to diagnose peripheral artery disease among people with diabetes mellitus: A systematic review

The accurate identification of peripheral artery disease (PAD) in patients with diabetes and foot ulceration is important, in order to inform timely management and to plan intervention including revascularisation. A variety of non-invasive tests are available to diagnose PAD at the bedside, but there is no consensus as to the most useful test, or the accuracy of these bedside investigations when compared to reference imaging tests such as magnetic resonance angiography, computed tomography angiography, digital subtraction angiography or colour duplex ultrasound. Members of the International Working Group of the Diabetic Foot updated our previous systematic review, to include all eligible studies published between 1980 and 2018. Some 15 380 titles were screened, resulting in 15 eligible studies (comprising 1563 patients, of which >80% in each study had diabetes) that evaluated an index bedside test for PAD against a reference imaging test. The primary endpoints were positive likelihood ratio (PLR) and negative likelihood ratio (NLR). We found that the most commonly evaluated test parameter was ankle brachial index (ABI) <0.9, which may be useful to suggest the presence of PAD (PLR 6.5) but an ABI value between 0.9 and 1.3 does not rule out PAD (NLR 0.31). A toe brachial index >0.75 makes the diagnosis of PAD less likely (NLR 0.14-0.24), whereas pulse oximetry may be used to suggest the presence of PAD (if toe saturation < 2% lower than finger saturation; PLR 17.23-30) or render PAD less likely (NLR 0.2-0.27). We found that the presence of triphasic tibial waveforms has the best performance value for excluding a diagnosis of PAD (NLR 0.09-0.28), but was evaluated in only two studies. In addition, we found that beside clinical examination (including palpation of foot pulses) cannot reliably exclude PAD (NLR 0.75), as evaluated in one study. Overall, the quality of data is generally poor and there is insufficient evidence to recommend one bedside test over another. While there have been six additional publications in the last 4 years that met our inclusion criteria, more robust evidence is required to achieve consensus on the most useful non-invasive bedside test to diagnose PAD.

Performance of prognostic markers in the prediction of wound healing or amputation among patients with foot ulcers in diabetes: A systematic review

Clinical outcomes of patients with diabetes, foot ulceration, and peripheral artery disease (PAD) are difficult to predict. The prediction of important clinical outcomes, such as wound healing and major amputation, would be a valuable tool to help guide management and target interventions for limb salvage. Despite the existence of a number of classification tools, no consensus exists as to the most useful bedside tests with which to predict outcome. We here present an updated systematic review from the International Working Group of the Diabetic Foot, comprising 15 studies published between 1980 and 2018 describing almost 6800 patients with diabetes and foot ulceration. Clinical examination findings as well as six non-invasive bedside tests were evaluated for their ability to predict wound healing and amputation. The most useful tests to inform on the probability of healing were skin perfusion pressure ≥ 40 mmHg, toe pressure ≥ 30 mmHg, or TcPO₂  ≥ 25 mmHg. With these thresholds, all of these tests increased the probability of healing by greater than 25% in at least one study. To predict major amputation, the most useful tests were ankle pressure < 50 mmHg, ABI < 0.5, toe pressure < 30 mmHg, and TcPO₂  < 25 mmHg, which increased the probability of major amputation by greater than 25%. These indicative values may be used as a guide when deciding which patients are at highest risk for poor outcomes and should therefore be evaluated for revascularization at an early stage. However, this should always be considered within the wider context of important co-existing factors such as infection, wound characteristics, and other comorbidities.

How to use clinical signs and symptoms to estimate the probability of limb ischaemia in patients with a diabetic foot ulcer

Assessment of ischaemia and interventions to improve perfusion are key elements in the management of the diabetic foot ulcer to achieve wound healing. This article will review, analyse and interpret the value of clinical information in determining the likelihood of limb ischaemia and thereby the need for referral to a vascular specialist. I conducted an historical review of the genesis of several currently recommended clinical signs and their diagnostic properties in the assessment of limb ischaemia. Changes in limb ischaemia probability based on such results were calculated using Bayes theorem, and the use of such probabilities is discussed in the context of the threshold approach to clinical decision making. Some clinical signs have negligible value in altering probability of limb ischaemia, possibly because they were advocated by Buerger for the diagnosis of thromboangiitis obliterans, an occlusive vascular disease of a different pathophysiology than atherosclerosis. Pedal pulse palpation, the most widely studied clinical sign, will marginally change a pre-test probability of ischaemia of 50% to 76% if positive (abnormal pulses) and to 36% if negative (normal pulses). Higher or lower pre-test probabilities of ischaemia will change the post-test probabilities such that these are too low or high to rule in or rule out ischaemia, respectively. Individual clinical signs convey little information regarding the presence of limb ischaemia but may have some value in combination or with pre-test probability near 50% in the assessment of ischaemia and the decision to refer for a vascular consultation.

Evaluation of a novel microfluidic immuno-magnetic agglutination assay method for detection of dengue virus NS1 antigen

BACKGROUND

Dengue virus (DENV) is the most important arbovirus worldwide, causing infections in endemic countries and returning travellers from these areas. Rapid diagnostic tests are needed to improve patient management and monitor local transmission. The detection of DENV non-structural protein 1 (NS1) is a useful tool for the diagnosis, but the currently available methods can be time consuming or lack sensitivity. The objective of our study was to evaluate a new rapid and semi-quantitative microfluidic DENV NS1 immuno-magnetic agglutination assay based on aggregation of magnetic nanoparticles detected by an electronic reader (Virotrack Dengue Acute and Blubox, Blusense diagnostics, Copenhagen, Denmark).

METHODOLOGY/PRINCIPAL FINDINGS

A panel of 135 serum samples from travelers returning from dengue endemic countries was analyzed (74 DENV positive samples including the four DENV serotypes, 26 Zika virus positive samples, 25 chikungunya virus positive samples, 5 malaria positive samples and 5 negative samples). Samples were tested by three different antigen detection methods: SD Dengue NS1 Ag ELISA, SD BIOLINE Dengue Duo and ViroTrack Dengue Acute. The sensitivity observed for SD Dengue NS1 Ag ELISA, ViroTrack Dengue Acute and SD BIOLINE Dengue Duo was 97.2%, 91.1% and 68.1%, respectively. All methods showed high specificity (98.4% for ViroTrack Dengue Acute and 100% for both SD Dengue NS1 Ag ELISA and SD BIOLINE Dengue Duo). SD Dengue NS1 Ag ELISA and ViroTrack Dengue Acute only failed to detect samples positive for DENV-2.

CONCLUSIONS/SIGNIFICANCE

ViroTrack Dengue Acute is a sensitive and specific assay for DENV NS1 detection. It provides faster results than the ELISA method and a better performance than the rapid immunochromatographic tests. ViroTrack Dengue Acute could represent a valuable tool for rapid diagnosis of DENV infections in returning travellers from endemic countries.