Validation of GeneXpert testing for SARS-CoV-2 RNA in eight hospital laboratories in Oman

In response to the current COVID-19 pandemic, numerous commercial assays have been developed for the detection of SARS-CoV-2 for use in the clinical diagnostic laboratories. To date, there is limited comparison of testing methods performed in different hospital laboratory sites. The aims of the study were to evaluate the analytical performance of Cepheid Xpert Xpress SARS-CoV-2 when compared to RT-PCR. This is a cross-sectional study. A total of 155 nasopharyngeal swabs were taken in duplicate from patients presenting with suspected COVID-19 to 8 hospitals in Oman. One swab was tested by the hospital laboratory and the duplicate swab was sent to the national Central Public Health Laboratory (CPHL) for testing. We compared the analytical performance of the commercially available point of care Cepheid Xpert Xpress SARS-CoV-2 assay which was used in the 8 different hospitals with assays including Liferiver, Sansure, TIB MOL BIOL, Kingfisher and COBAS 6800 by Roche which were performed at the CPHL. Testing of the duplicate swabs revealed excellent agreement of results with the viral loads of Ct values ranging from 16-43 for the E gene, 18-44 for the N gene and 17-44 for the ORF gene using the Liferiver assay. The overall sample sensitivity and specificity of the Cepheid Xpert Xpress SARS-CoV-2 assay were both 100% and there was 100% agreement across specimens. We conclude that the rapid GeneXpert and RT-PCR kits assessed in this study may be used for routine diagnostic testing of COVID-19 patients by experienced clinical microbiology diagnostic laboratories. Our results highlight the importance of rapid molecular testing at different sites within a country in a public health emergency.

Laboratory-based surveillance of COVID-19 in the Greater Helsinki area, Finland, February-June 2020

OBJECTIVES

The aim was to characterise age- and sex-specific severe acute respiratory syndrome coronavirus disease-2 (SARS-CoV-2) RT-PCR sampling frequency and positivity rate in Greater Helsinki area in Finland during February-June 2020. We also describe the laboratory capacity building for these diagnostics.

METHODS

Laboratory registry data for altogether 80,791 specimens from 70,517 individuals was analysed. The data included the date of sampling, sex, age and the SARS-CoV-2 RT-PCR test result on specimens collected between 1 February and 15 June 2020.

RESULTS

Altogether, 4057/80,791 (5.0%) of the specimens were positive and 3915/70,517 (5.6%) of the individuals were found positive. In all, 37% of specimens were from male and 67% from female subjects. While the number of positive cases was similar in male and female subjects, the positivity rate was significantly higher in male subjects: 7.5% of male and 4.4% of female subjects tested positive. The highest incidence/100,000 was observed in those aged ≥80 years. The proportion of young adults in positive cases increased in late May 2020. Large dips in testing frequency were observed during every weekend and also during public holidays.

CONCLUSIONS

Our data suggest that men pursue SARS-CoV-2 testing less frequently than women. Consequently, a subset of coronavirus disease-2019 infections in men may have gone undetected. People sought testing less frequently on weekends and public holidays, and this may also lead to missing of positive cases. The proportion of young adults in positive cases increased towards the end of the study period, which may suggest their returning back to social behaviour with an increased risk of infection.

Evaluation of in-service training program of laboratory professionals in Amhara Public Health Institute Dessie Branch, northeast Ethiopia: A concurrent mixed-method study

Background

In-service training programs should be evaluated and modified regularly to enhance training quality. However, in Ethiopia, there is no published evidence regarding its effectiveness. Therefore, we evaluated the Amhara Public Health Institute Dessie Branch (APHI_DB) in-service training program using the Kirkpatrick model.

Methods

In October 2019, a concurrent nested mixed method facility-based cross-sectional study was conducted among 107 laboratory stakeholders from 22 randomly selected government health facilities in the eastern part of the Amhara region. The qualitative part involved interviews with each of these key stakeholders. We collected data using a semi-structured questionnaire through face-to-face interviews. EpiData 3.1 and Microsoft Excel 2016 software were used for data entry and analysis respectively. The major qualitative findings were narrated and summarized based on four thematic areas to supplement the quantitative findings.

Results

A total of 107 laboratory personnel were interviewed, which makes a response rate of 97.3%. At the reaction level, 82.1% of the participants agree/strongly agree with the course structures, training contents, and learning tools. Likewise, 85.4% of the participants agreed/ strongly agreed on the trainer’s knowledge and their communication skills. In addition, 93.1% of the participants stated an improvement in knowledge and skills after attending the training. As a result, 65.6% of them were able to transfer their knowledge and skills into practice. Regarding the training set-ups and environment, 45.1% of the respondents disagree/strongly disagree with the training hall, toilet, cafe, tea and snacks, financial process, and accommodation perdiem.

Conclusion

Generally, the laboratory in-service training program of APHI_DB was more or less effective. Our findings suggest regular monitoring of each training event and evaluation of training programs against a clearly defined criterion. Furthermore, the institute is mandated to create a conducive learning environment and well-established training setups for trainees.

Adaptation of Clinical Laboratories to COVID 19 Pandemic: Changes in Test Panels, Overcoming Problems and Preparation Suggestions for Future Pandemics Adaptation of Clinical Laboratories to COVID 19 Pandemic

BACKGROUND

For Coronavirus Disease 2019 (Covid-19) infection, clinical laboratories provide essential contributions in the diagnosis of infection, stage prognostication, and evaluation of disease severity. We aimed to show laboratory problems including changes of test numbers, changes of test panels, and differences of preanalytical errors during Covid-19 pandemic and, in the current study, we also intended to give solutions for the obstacles to guide other possible pandemics.

METHODS

Our study was based on data between January 10, 2020, and May 10, 2020. The first Covid-19 case of the Republic of Turkey was seen March 10, 2020, which was determined as the threshold date for comparisons. This was a single center, data mining, retrospective study.

RESULTS

The number of patients admitted to hospital were 34,260 and 15,573, the number of total tests were 66,263 and 42,066 before and after pandemic, respectively, for the two-month interval. Test percentage changes were increased for D-dimer 136%, fibrinogen 3,113%, troponin 6%, and LDH 17%. Test percentage changes were decreased for CBC 37%, sedimentation 45%, aPTT 30%, PT 37%, CRP 28%, ProCT 10%, ferritin 29%, CK-MB 27%, blood gases 47%, ALT 43%, AST 42%, urea 42%, creatinine 42%, triglycerides 45%, sodium 42%, potassium 41%, chloride 21%, urine culture 58%, and blood culture 44%. When preanalytical sources of errors were investigated no differences were found.

CONCLUSIONS

Laboratories must take quick action and be prepared for changes in patient services during pandemics. The most reliable ways for this are past experiences, statistical analysis, co-operation with administrations, high quality communication skills, and a risk-based management system.

Extended storage of SARS-CoV-2 nasopharyngeal swabs does not negatively impact results of molecular-based testing across three clinical platforms

With the global outbreak of COVID-19, the demand for testing rapidly increased and quickly exceeded the testing capacities of many laboratories. Clinical tests which receive CE (Conformité Européenne) and Food and Drug Administration (FDA) authorisations cannot always be tested thoroughly in a real-world environment. Here we demonstrate the long-term stability of nasopharyngeal swab specimens for SARS-CoV-2 molecular testing across three assays recently approved by the US FDA under Emergency Use Authorization. This study demonstrates that nasopharyngeal swab specimens can be stored under refrigeration or even ambient conditions for 21 days without clinically impacting the results of the real-time reverse transcriptase-PCR testing.

The implementation of a rapid sample preparation method for the detection of SARS-CoV-2 in a diagnostic laboratory in South Africa

The SARS-CoV-2 pandemic has resulted in shortages of both critical reagents for nucleic acid purification and highly trained staff as supply chains are strained by high demand, public health measures and frequent quarantining and isolation of staff. This created the need for alternate workflows with limited reliance on specialised reagents, equipment and staff. We present here the validation and implementation of such a workflow for preparing samples for downstream SARS-CoV-2 RT-PCR using liquid handling robots. The rapid sample preparation technique evaluated, which included sample centrifugation and heating prior to RT-PCR, showed a 97.37% (95% CI: 92.55-99.28%) positive percent agreement and 97.30% (95% CI: 90.67-99.52%) negative percent agreement compared to nucleic acid purification-based testing. This method was subsequently adopted as the primary sample preparation method in the Groote Schuur Hospital Virology Diagnostic Laboratory in Cape Town, South Africa.

Staining Performance of ALK and ROS1 Immunohistochemistry and Influence on Interpretation in Non-Small-Cell Lung Cancer

Selection of non-small-cell lung cancer patients for treatment relies on the detection of expression of anaplastic lymphoma kinase (ALK) and ROS proto-oncogene 1 (ROS1) protein by immunohistochemistry (IHC). We evaluated staining performance for different IHC protocols and laboratory characteristics, and their influence on ALK and ROS1 interpretation during external quality assessment schemes between 2015 and 2018. Participants received five formalin-fixed, paraffin-embedded cases for staining by their routine protocol, whereafter at least two pathologists scored them simultaneously under a multihead microscope and awarded a graded expert staining score (ESS) from 1 to 5 points based on staining quality. European Conformity in Vitro Diagnostic kits (such as D5F3) revealed a better ALK ESS compared with laboratory-developed tests. ESS was indifferent to the applied antibody dilution or a recent protocol change. Lower ESSs were observed for higher antibody incubation times and temperatures. ESS for various ROS1 protocols were largely similar. Overall, for both markers, ESS improved over time and for repeated external quality assessment participation but was independent of laboratory setting or experience. Except for ROS1, ESS positively correlated with laboratory accreditation. IHC stains with lower ESS correlated with increased error rates in ALK and ROS1 interpretation and analysis failures. Laboratory characteristics differently affected staining quality and interpretation, and laboratories should assess both aspects, and less common protocols need improvement in staining performance.

Be cautious during the interpretation of arterial blood gas analysis performed outside the intensive care unit

INTRODUCTION

Reliable results of an arterial blood gas (ABG) analysis are crucial for the implementation of appropriate diagnostics and therapy. We aimed to investigate the differences (Δ) between ABG parameters obtained from point-of-care testing (POCT) and central laboratory (CL) measurements, taking into account the turnaround time (TAT).

MATERIALS AND METHODS

A number of 208 paired samples were collected from 54 intensive care unit (ICU) patients. Analyses were performed using Siemens RAPIDPoint 500 Blood Gas System on the samples just after blood retrieval at the ICU and after delivery to the CL.

RESULTS

The median TAT was 56 minutes (IQR 39-74). Differences were found for all ABG parameters. Median Δs for acid-base balance ere: ΔpH=0.006 (IQR -0.0070-0.0195), ΔBEef=-0.9 (IQR -2.0-0.4) and HCO3-act=-1.05 (IQR -2.25-0.35). For ventilatory parameters they were: ΔpO2=-8.3 mmHg (IQR -20.9-0.8) and ΔpCO2=-2.2 mmHg (IQR -4.2--0.4). For electrolytes balance the differences were: ΔNa+=1.55 mM/L (IQR 0.10-2.85), ΔK+=-0.120 mM/L (IQR -0.295-0.135) and ΔCl-=1.0 mM/L (IQR -1.0-3.0). Although the Δs might have caused misdiagnosis in 51 samples, Bland-Altman analysis revealed that only for pO2 the difference was of clinical significance (mean: -10.1 mmHg, ±1.96SD -58.5; +38.3). There was an important correlation between TAT and ΔpH (R=0.45, p<0.01) with the safest time delay for proper assessment being less than 39 minutes.

CONCLUSIONS

Differences between POCT and CL results in ABG analysis may be clinically important and cause misdiagnosis, especially for pO2. POCT should be advised for ABG analysis due to the impact of TAT, which seems to be the most important for the analysis of pH.

Analysis of Prescribed Critical Values in Istanbul Training and Research Hospital Biochemistry Laboratory: Should Critical Values Be Repeated?

BACKGROUND

Clinically important critical values must be readily available to the clinician. Repeating critical values may cause a delay. In this study, we evaluated the requirement of repeating critical values.

METHODS

We extracted initial and repeated critical values and reporting times for a six-month period via the hospital laboratory information management system. Ten parameters from our critical value list (glucose, urea, mag-nesium (Mg++), calcium (Ca++), sodium (Na+), potassium (K+), chloride (Cl-), white blood cells (WBC), platelets, hemoglobin) were evaluated. We assessed whether the difference between the first measurement of the initial critical value and the repeated measurement value exceeded total allowable error (TEa).

RESULTS

Repeated critical values of Mg++, Ca++, WBC, platelets, and hemoglobin did not exceed TEa. However, repeated critical values of glucose, urea, Na+, K+, and Cl- did exceed TEa. In addition, parameters such as glucose and urea did not affect the clinical decision although their critical values exceeded the TEa. This study showed that critical values for Na+, K+, and Cl- may need to be repeated.

CONCLUSIONS

Each laboratory should assess the requirement of repeating critical values under its own operating conditions and, accordingly, establish and implement a suitable policy.

Reproductive outcomes and Y chromosome instability in radiation-exposed male workers in cardiac catheterization laboratory

Occupational radiation exposure may impact the reproductive outcome of male workers in the cardiac catheterization laboratory (cath Lab) who receive a dose of ~1-10 mSv/year. An increased copy number variation (CNV) in azoospermia factor region c (AZFc) of the Y chromosome is a marker of spermatogenic failure, previously associated with radiation exposure. This study sought to investigate the association between paternal exposure in the Cath Lab and adverse reproductive outcomes as well as to assess the induction of CNV in the AZFc region. In a case-control study, we enrolled 193 catheterization lab workers (Group I) and 164 age-matched unexposed controls (Group II). Reproductive outcomes were assessed through a structured questionnaire. Two sequence-tagged sites (SY1197 and SY579) in AZFc region were evaluated by qRT-PCR in 83 exposed and 47 unexposed subjects. Exposed workers had a higher prevalence of low birth weight in offspring (Group I = 13% vs. II = 5.3%, P = 0.02; OR_adjusted = 2.7; 95% CI: 1.1-6.3; P = 0.02). The mean of CNV (microdeletion and microduplication) for SY1197 was significantly higher in the exposed workers (Group I = 1.53 ± 0.85 vs. Group II = 1.02 ± 0.41; P = 0.0005). Despite the study design limitations, our findings show that chronic occupational radiation exposure of male workers is correlated with higher prevalence of low birth weight in offspring and instability in the Y chromosome AZFc region. Environ. Mol. Mutagen. 61:361-368, 2020. © 2019 Wiley Periodicals, Inc.

Diagnosis of Gestational Diabetes Mellitus with Point-of-Care Methods for Glucose versus Hospital Laboratory Method Using Isotope Dilution Gas Chromatography-Mass Spectrometry as Reference

BACKGROUND

In Sweden, both glucose analyzers in accredited laboratories and point-of-care glucose devices are used for gestational diabetes mellitus (GDM) diagnosis. The aim of this study was to compare the diagnostic performance of the HemoCue Glucose 201+ (HC201+) and RT (HC201RT) systems with that of the hospital central laboratory hexokinase method (CL) based on lyophilized citrate tubes, using the isotope dilution gas chromatography-mass spectrometry (ID GC-MS) as reference.

METHODS

A 75 g oral glucose tolerance test was performed on 135 women screened positive for GDM. Diagnosis was based on the World Health Organization 2013 diagnostic thresholds for fasting (n = 135), 1 h (n = 135), 1 h (n = 135), 1 h (.

RESULTS

Significantly more women were diagnosed with GDM by HC201+ (80%) and CL (80%) than with the reference (65%, P < 0.001) based on fasting and/or 2 h thresholds, whereas the percentage diagnosed by HC201RT (60%) did not differ significantly from the reference. In Bland-Altman analysis, a positive bias was observed for HC201+ (4.2%) and CL (6.1%) and a negative bias for HC201RT (-1.8%). In the surveillance error grid, 95.9% of the HC201+ values were in the no-risk zone as compared to 98.1% for HC201RT and 97.5% for CL.

CONCLUSIONS

A substantial positive bias was found for CL measurements resulting in overdiagnosis of GDM. Our findings suggest better performance of HC201RT than HC201+ in GDM diagnosis. The results may have possible implications for GDM diagnosis in Sweden and require further elucidation.

Macroepidemiological aspects of porcine reproductive and respiratory syndrome virus detection by major United States veterinary diagnostic laboratories over time, age group, and specimen

This project investigates the macroepidemiological aspects of porcine reproductive and respiratory syndrome virus (PRRSV) RNA detection by veterinary diagnostic laboratories (VDLs) for the period 2007 through 2018. Standardized submission data and PRRSV real-time reverse-transcriptase polymerase chain reaction (RT-qPCR) test results from porcine samples were retrieved from four VDLs representing 95% of all swine samples tested in NAHLN laboratories in the US. Anonymized data were retrieved and organized at the case level using SAS (SAS® Version 9.4, SAS® Institute, Inc., Cary, NC) with the use of PROC DATA, PROC MERGE, and PROC SQL scripts. The final aggregated and anonymized dataset comprised of 547,873 unique cases was uploaded to Power Business Intelligence-Power BI® (Microsoft Corporation, Redmond, Washington) to construct dynamic charts. The number of cases tested for PRRSV doubled from 2010 to 2018, with that increase mainly driven by samples typically used for monitoring purposes rather than diagnosis of disease. Apparent seasonal trends for the frequency of PRRSV detection were consistently observed with a higher percentage of positive cases occurring during fall or winter months and lower during summer months, perhaps due to increased testing associated with well-known seasonal occurrence of swine respiratory disease. PRRSV type 2, also known as North American genotype, accounted for 94.76% of all positive cases and was distributed across the US. PRRSV type 1, also known as European genotype, was geographically restricted and accounted for 2.15% of all positive cases. Co-detection of both strains accounted for 3.09% of the positive cases. Both oral fluid and processing fluid samples, had a rapid increase in the number of submissions soon after they were described in 2008 and 2017, respectively, suggesting rapid adoption of these specimens by the US swine industry for PRRSV monitoring in swine populations. As part of this project, a bio-informatics tool defined as Swine Disease Reporting System (SDRS) was developed. This tool has real-time capability to inform the US swine industry on the macroepidemiological aspects of PRRSV detection, and is easily adaptable for other analytes relevant to the swine industry.

Incomplete Filling of Laboratory Request Forms: A Look at the Practice at a Federal Medical Centre in South Eastern Nigeria

BACKGROUND

Laboratory request forms serve as a medium for communication between clinicians managing medical cases and the pathologist. Improperly filled forms impairs the ability of pathologists to generate sound and valuable reports. This research focused on finding out the extent to which doctors in Federal Medical Centre, Umuahia properly fill laboratory request forms.

METHODOLOGY

A total of 1,509 laboratory request forms directed to the electrolyte bench, already filled out by various doctors in the hospital between May and October, 2018 were retrospectively studied. The completeness of information supplied by requesting physician based on some parameters were analysed.

RESULTS

In descending order, the most frequently provided data were as follows; name of patient, 1,509[100.0%]; gender,973[64.5%]; provisional diagnosis,866[57.4%]; age,639[42.4%]; hospital number,428[28.4%]; clinical summary,47[3.1%]. 26[2%] forms were completed in their entirety per the 6 variables assessed.

CONCLUSION

Proper and adequate filling of laboratory request forms is very poor in this hospital. Therefore, continuous medical education on the need for adequate completion of request forms is absolutely necessary.

Algorithm to Estimate the Extended Turnaround Time Including Outpatient Waiting Time for Blood Specimen Collection when a Stand-alone Queue Ticket System not Connectable to Laboratory Information System Is Used

BACKGROUND

A queue ticket system (QTS) used in an outpatient phlebotomy clinic was unable to be directly integrated with the laboratory information system (LIS). To monitor patient's waiting time and extended turnaround time (TAT) as patient-centered quality indicators for outpatient laboratory services, we developed an algorithm to integrate data between the QTS and the LIS.

METHODS

Between June 1 to September 30, 2017, data files were exported from a QSYS-8000 (HION Tech, Seoul, Korea). Each calling event from the QTS data was matched to a barcode of test requests from the LIS if the following conditions were met: (1) time interval between "call time" from QTS and "barcode printing time" from LIS <90 s; (2) "Counter Number" from LIS="Counter Number" from QTS. Extended TAT was estimated as the interval between pulling the queue ticket and the reporting of the test result.

RESULTS

82.66%±3.14% of the barcodes from the LIS were matched to issued tickets. Median waiting time (mean±SD) was 6.5±5.3 min. Median extended TAT was 84.7±11.2 min for non-STAT and 53.0±6.4 min for STAT.

CONCLUSION

When a stand-alone QTS was used in the outpatient phlebotomy clinic, data from the QTS and the LIS were integrated using a novel algorithm we developed.

Clostridium difficile colonization among patients with clinically significant diarrhea and no identifiable cause of diarrhea

OBJECTIVE

To determine the prevalence of Clostridium difficile colonization among patients who meet the 2017 IDSA/SHEA C. difficile infection (CDI) Clinical Guideline Update criteria for the preferred patient population for C. difficile testing.

DESIGN

Retrospective cohort.

SETTING

Tertiary-care hospital in St. Louis, Missouri.PatientsPatients whose diarrheal stool samples were submitted to the hospital's clinical microbiology laboratory for C. difficile testing (toxin EIA) from August 2014 to September 2016.InterventionsElectronic and manual chart review were used to determine whether patients tested for C. difficile toxin had clinically significant diarrhea and/or any alternate cause for diarrhea. Toxigenic C. difficile culture was performed on all stool specimens from patients with clinically significant diarrhea and no known alternate cause for their diarrhea.

RESULTS

A total of 8,931 patients with stool specimens submitted were evaluated: 570 stool specimens were EIA positive (+) and 8,361 stool specimens were EIA negative (-). Among the EIA+stool specimens, 107 (19% of total) were deemed eligible for culture. Among the EIA- stool specimens, 515 (6%) were eligible for culture. One EIA+stool specimen (1%) was toxigenic culture negative. Among the EIA- stool specimens that underwent culture, toxigenic C. difficile was isolated from 63 (12%).

CONCLUSIONS

Most patients tested for C. difficile do not have clinically significant diarrhea and/or potential alternate causes for diarrhea. The prevalence of toxigenic C. difficile colonization among EIA- patients who met the IDSA/SHEA CDI guideline criteria for preferred patient population for C. difficile testing was 12%.

Removing Lipemia in Serum/Plasma Samples: A Multicenter Study

BACKGROUND

Lipemia, a significant source of analytical errors in clinical laboratory settings, should be removed prior to measuring biochemical parameters. We investigated whether lipemia in serum/plasma samples can be removed using a method that is easier and more practicable than ultracentrifugation, the current reference method.

METHODS

Seven hospital laboratories in Spain participated in this study. We first compared the effectiveness of ultracentrifugation (108,200×g) and high-speed centrifugation (10,000×g for 15 minutes) in removing lipemia. Second, we compared high-speed centrifugation with two liquid-liquid extraction methods-LipoClear (StatSpin, Norwood, USA), and 1,1,2-trichlorotrifluoroethane (Merck, Darmstadt, Germany). We assessed 14 biochemical parameters: serum/plasma concentrations of sodium ion, potassium ion, chloride ion, glucose, total protein, albumin, creatinine, urea, alkaline phosphatase, gamma-glutamyl transferase, alanine aminotransferase, aspartate-aminotransferase, calcium, and bilirubin. We analyzed whether the differences between lipemia removal methods exceeded the limit for clinically significant interference (LCSI).

RESULTS

When ultracentrifugation and high-speed centrifugation were compared, no parameter had a difference that exceeded the LCSI. When high-speed centrifugation was compared with the two liquid-liquid extraction methods, we found differences exceeding the LCSI in protein, calcium, and aspartate aminotransferase in the comparison with 1,1,2-trichlorotrifluoroethane, and in protein, albumin, and calcium in the comparison with LipoClear. Differences in other parameters did not exceed the LCSI.

CONCLUSIONS

High-speed centrifugation (10,000×g for 15 minutes) can be used instead of ultracentrifugation to remove lipemia in serum/plasma samples. LipoClear and 1,1,2-trichlorotrifluoroethane are unsuitable as they interfere with the measurement of certain parameters.

Comparison between Two Methods in the Determination of Circulating Chromogranin A in Neuroendocrine Tumors (NETs): Results of a Prospective Multicenter Observational Study

Several methods for analyzing CgA using either monoclonal or polyclonal antibodies have been developed, which differ in their diagnostic performance. The present paper describes the results of a prospective multicenter study aimed at comparing the clinical value of the two most widely used commercially available CgA assay kits in patients affected by neuroendocrine tumors (NETs). Two hundred sixty-one patients from 40 different centers and 99 healthy subjects were evaluated. CgA levels were measured with two different methods, a two-step immunoradiometric assay (IRMA) and an enzyme-linked immunosorbent assay (ELISA). CgA was measured centrally by two reference laboratories, one of which used IRMA and the other ELISA, and it was measured by the participating institutions with the method routinely used by each of them. The major findings of the present study were: (i) the two assays for the determination of CgA present good diagnostic performance; (ii) both assays are robust and guarantee comparable results when applied in different settings (central vs local laboratory); (iii) the negative/positive cutoff points (87 ng/mL for IRMA and 21.3 U/L for ELISA) were established according to standardized criteria; (iv) the results obtained with the two assays in basal clinical samples of patients affected by NETs show an apparently satisfactory correlation (rs=0.843, p<0.0001). However, a possibly clinically meaningful 36% discordance rate was found. These findings support the hypothesis that the two CgA kits might provide partially different information.

In vitro activity of eravacycline against 2213 Gram-negative and 2424 Gram-positive bacterial pathogens isolated in Canadian hospital laboratories: CANWARD surveillance study 2014-2015

Gram-negative (n=2213) and Gram-positive (n=2424) pathogens isolated from patients in 13 Canadian hospitals in 2014 and 2015 were tested for in vitro susceptibility to eravacycline and comparators using the Clinical and Laboratory Standards Institute broth microdilution method. The concentration of eravacycline inhibiting 90% of isolates (MIC₉₀) ranged from 0.5 to 2μg/mL for 9 species of Enterobacteriaceae tested (n=2067). Eravacycline activity was largely unaffected by extended-spectrum β-lactamase phenotypes in Escherichia coli (n=141) and Klebsiella pneumoniae (n=21). Eravacycline was active against Acinetobacter baumannii (n=28; MIC₉₀, 0.5μg/mL) and Stenotrophomonas maltophilia (n=118; MIC₉₀, 4μg/mL). Eravacycline MIC₉₀ for staphylococci (n=1653), enterococci (n=289), and streptococci (n=482) ranged from 0.12 to 0.25, 0.06 to 0.12, and 0.015 to 0.06μg/mL, respectively. Eravacycline's potency was equivalent to or 2- to 4-fold greater than tigecycline against Enterobacteriaceae and Gram-positive cocci tested. Eravacycline demonstrates promising activity against recent clinical Gram-negative and Gram-positive bacteria, including multidrug-resistant pathogens.

Diagnostic performance of point-of-care and central laboratory cardiac troponin assays in an emergency department

Early diagnosis of myocardial infarction (MI) with cardiac troponin (cTn) assays at the point-of-care (POC) is suggested to shorten turn-around-time in the emergency department (ED). The present study aimed at comparing the diagnostic performance of two POC cTn assays with that of a central laboratory high-sensitivity (hs) method, under routine ED conditions. In 2,163 non-selected ED patients suspected for MI, the diagnostic performance of the POC troponin I (TnI), troponin T (TnT), and hs-TnT assay for the prediction of MI was evaluated based on receiver operating characteristic (ROC) analyses and compared with the performance based on the manufacturers' cut-offs. Due to an observed association between renal function as determined by estimated glomerular filtration rate (eGFR) and cTn concentrations, all analyses were stratified by renal function. In patients with normal renal function (eGFR > 60 mL/min/1.73m2), POC and hs assays showed a comparable diagnostic performance as quantified by the area under the ROC curve (AUC) of about 0.88. The ROC-derived optimal cut-off (OCO) levels for the different cTn assays clearly changed with decreasing kidney function. Impaired kidney function required OCO to be three to five times higher to achieve a comparable performance. Particularly cTnT concentrations were strongly associated with renal function. The three cTn assays demonstrated equivalent diagnostic performance in ED-patients admitted with suspected ACS in relation to the release diagnosis, supporting the use of POC testing in this setting. The present results implicate that application of eGFR-specific OCOs may decrease false-positives among patients with impaired renal function. Providing individual cut-offs depending on patients' eGFR might be an appropriate add-on tool to improve specificity in the diagnosis of MI.

Susceptibility pattern of methicillin resistant Staphylococcus aureus to vancomycin and other alternate agents: report from a private sector hospital laboratory

With increasing prevalence of methicillin resistant Staphylococcus aureus in clinical settings and injudicious use of antibiotics, resistance among MRSA against commonly used antibiotics is increasing. To assess the susceptibility pattern of MRSA against vancomycin, linezolid, tigecycline, rifampicin, fosfomycin fusidic acid, clindamycin, trimethoprim-sulfamethoxazole and teicoplanin, minimum inhibitory concentrations (MICs) for given antimicrobials were performed on 234 MRSA clinical isolates using automated VITEK 2 system. Vancomycin, linezolid, rifampicin, clindamycin, co-trimoxazole and teicoplanin susceptibilities were interpreted according to CLSI breakpoints, while tigecycline, fosfomycin and fusidic acid were interpreted according to BSAC breakpoints. All isolates were found susceptible to vancomycin, tigecycline, teicoplanin and linezolid. Non-susceptibility of the isolates for rifampicin, fusidic acid and fosfomycin was noted for 58(25%). Co-trimoxazole and clindamycin were found less susceptible showing high resistance rates of 61.5% and 42.3%, respectively. Vancomycin resistance was not found, however an increased MIC of 1 mg/ml was observed in about 25% of clinical strains. Increase in vancomycin MICs in MRSA is of concern and alternative antimicrobial options must be evaluated and considered for treatment of MRSA infections. Continuous antimicrobial surveillance is needed to monitor resistance patterns and detect possible emergence of vancomycin non-susceptible isolates.

The effects of culture independent diagnostic testing on the diagnosis and reporting of enteric bacterial pathogens in Queensland, 2010 to 2014

Changes in diagnostic laboratory testing procedures can impact on the number of cases notified and the public health surveillance of enteric pathogens. Culture independent diagnostic testing using a multiplex polymerase chain reaction (PCR) test was introduced for the rapid detection of bacterial enteric pathogens in pathology laboratories in Queensland, Australia, from late 2013 onwards. We conducted a retrospective descriptive study using laboratory data to assess the impact of the introduction of PCR testing on four common enteric pathogens, Salmonella, Campylobacter, Shigella and Yersinia, in Queensland between 2010 and 2014. The number of stool specimens tested and the proportion positive for each of the four pathogens increased in 2014 after the introduction of culture independent diagnostic testing. Among the specimens tested by both PCR and culture, 12% of Salmonella positive stools, 36% of Campylobacter positive stools, 74% of Shigella / enteroinvasive Escherichia coli positive stools and 65% of Yersinia positive stools were PCR positive only. Including those where culture was not performed, 19% of Salmonella positive stools, 44% of Campylobacter positive stools, 83% of Shigella positive stools and 79% of Yersinia positive stools had no cultured isolate available for further characterisation. The detection and tracking of foodborne and non-foodborne gastrointestinal outbreaks will become more difficult as culture independent diagnostic testing becomes more widespread. Until new techniques for characterisation of pathogens directly from clinical specimens have been developed, we recommend laboratories continue to culture specimens concurrently or reflexively with culture independent diagnostic tests.