Prospective evaluation of the Alere i Influenza A&B nucleic acid amplification versus Xpert Flu/RSV

Usefulness of rapid molecular tests in pediatric respiratory tract infections

OBJECTIVE

To evaluate the role and the advantages of nasopharyngeal swabs in the detection of Influenza A and B viruses and Respiratory syncytial virus through a rapid test based upon a nucleic acid amplification reaction in order to avoid improper antibiotics use.

DESIGN

Case-control retrospective study.

SETTING

Emergency Room of "Sandro Pertini" General Hospital, Rome, Italy.

PARTICIPANTS

Children (< 14 years old) who consecutively arrived in the Emergency Department (ED) for respiratory tract infections, without obvious signs of bacterial respiratory tract infections and other comorbidities, in the maximal seasonal incidence period of November-to-March of every year between 2016 and 2020.

METHODS

Medical records of children included in the study were retrospectively examined. Children were subdivided according to the following intervals: 2016-2017 and 2017-2018 (Group 1), 2018-2019 and 2019-2020 (Group 2). Children in Group 2 undertook a nasopharyngeal swab, while those in Group 1 did not undergo any specific diagnostic test.

PRIMARY OUTCOME

Avoidance of improper antibiotics administration.

RESULTS

A total of 386 children were included in the study: 174 in Group 1, 212 in Group 2. The Odd Ratio (OR) of prescribing an antibiotic in the groups of children not being swabbed compared to those of children undertaking a swab was 9.21 (CI95% 5.6-15.2, p < 0.001). The overall percentage of hospitalizations, both in the short observation unit or in the pediatric unit, did not differ between the two groups.

CONCLUSIONS

Nasopharyngeal swabs for the detection of Influenza A and B viruses and Respiratory syncytial virus proved to be a useful means to a correct and timely diagnosis and allowed for a significant reduction in the prescription of antibiotic therapy.

TRIAL REGISTRATION

Retrospectively registered.

Clinical and operational impact of rapid point-of-care SARS-CoV-2 detection in an emergency department

Study objective

Rapid point-of-care (POC) SARS-CoV-2 detection with Abbott ID NOW™ COVID-19 test has been implemented in our Emergency Department (ED) for several months. We aimed to evaluate the operational impact and potential benefits of this innovative clinical pathway.

Methods

We conducted a prospective, descriptive, interventional, non-randomized study, before-after trial with the comparison of patient cohorts from two consecutive periods of seven weeks (observational pre-POC period vs interventional POC period).

Results

In 2020, throughout weeks 37 to 50, 3333 patients were assessed for eligibility and among them 331 (9.9%) were positive for SARS-CoV-2 infections. Among the included patients, 136 (9.2%) were positive for SARS-CoV-2 infection in the pre-POC period and 195 (10.5%) in the POC period. Among positive patients for SARS-CoV-2 related infection in-hospital mortality rate was similar between the two groups but the hospitalization rate was higher in the POC group (81.6% vs. 65.4%; p < 0.001). More patients in the POC period were able to leave the ED within 6 h. We examined rates of antibiotic, anticoagulant, and corticosteroid prescriptions among patients tested for SARS-CoV-2 in the ED. Only the rate of prescribed anticoagulants was found to be higher in the POC period (40% vs. 24.2%; p < 0.003).

Conclusion

We demonstrated that COVID-19 point-of-care testing speeds up clinical decision-making, improving use of recommended treatments for COVID-19, such as anticoagulants. Moreover, it improves the boarding time and significantly shortened the length of stay in the ED for patients requiring outpatient care.

Prospective evaluation of ID NOW COVID-19 assay used as point-of-care test in an emergency department

BACKGROUND

Rapid testing for COVID-19 has been clearly identified as an essential component of the strategy to control the SARS-CoV-2 epidemic, worldwide. The ID NOW COVID-19 assay is a simple, user-friendly, rapid molecular biology test based on nicking and extension amplification reaction (NEAR).

OBJECTIVES

The aim of this study was to evaluate the ID NOW COVID-19 assay when used as a point-of-care test (POCT) in our Emergency Department (ED).

TYPE OF STUDY

This prospective study enrolled 395 consecutive patients; paired nasopharyngeal swabs were collected from each study participant. The first swab was tested with the ID NOW COVID-19 assay at the point-of-care by ED nurses. The second swab was diluted in viral transport medium (VTM) and sent to the clinical microbiology department for analysis by both the RT-PCR Simplexa test COVID-19 Direct assay as the study reference method, and the ID NOW COVID-19 assay performed in the laboratory.

RESULTS

Nasopharyngeal swabs directly tested with the ID NOW COVID-19 assay yielded a sensitivity, specificity, PPV and NPV of 98.0%, 97.5%, 96.2% and 98.7%, respectively, in comparison with the RT-PCR study reference assay. When the ID NOW COVID-19 assay was performed in the laboratory using the VTM samples, the sensitivity decreased to 62.5% and the NPV to 79.7%. Three false negative test results were reported with the ID NOW COVID-19 assay when performed using undiluted swabs directly in the ED; these results were obtained from patients with elevated CT values (> 30).

CONCLUSION

We demonstrated that the ID NOW COVID-19 assay, performed as a point of care test in the ED using dry swabs, provides a rapid and reliable alternative to laboratory-based RT-PCR methods.

Management of hospitalized influenza A patients during the season 2018/19 : Comparison of three medical departments and the effect on outcome and antibiotic usage

BACKGROUND

Diagnosis and treatment of influenza patients are often provided across several medical specialties. We compared patient outcomes at an infectious diseases (ID), a rheumatology (Rheu) and a pulmonology (Pul) department.

MATERIAL AND METHODS

In this prospective observational multicenter study we included all influenza positive adults who were hospitalized and treated at flu isolation wards in three hospitals in Vienna during the season 2018/2019.

RESULTS

A total of 490 patients (49% female) with a median age of 73 years (interquartile range [IQR] 61-82) were included. No differences regarding age, sex and most underlying diseases were present at admission. Frequencies of the most common complications differed: acute kidney failure (ID 12.7%, Rheu 21.2%, Pulm 37.1%, p < 0.001), acute heart failure (ID 4.3%, Rheu 17.1%, Pulm 14.4%, p < 0.001) and respiratory insufficiency (ID 45.1%, Rheu 41.5%, Pulm 56.3%, p = 0.030). Oseltamivir prescription was lowest at the pulmonology flu ward (ID 79.6%, Rheu 90.5%, Pulm 61.7%, p < 0.001). In total 176 patients (35.9%) developed pneumonia. Antibiotic selection varied between the departments: amoxicillin/clavulanic acid (ID 28.9%, Rheu 63.8%, Pulm 5.9%, p < 0.001), cefuroxime (ID 28.9%, Rheu 1.3%, Pulm 0%, p < 0.001), 3rd generation cephalosporins (ID 4.4%, Rheu 5%, Pulm 72.5%, p < 0.001), doxycycline (ID 17.8%, Rheu 0%, Pulm 0%, p < 0.001). The median length of stay was significantly different between wards: ID 6 days (IQR 5-8), Rheu 6 days (IQR 5-7) and Pulm 7 days (IQR 5-9.5, p = 0.034). In-hospital mortality was 4.3% and did not differ between specialties.

CONCLUSION

We detected differences in oseltamivir usage, length of in-hospital stay and antibiotic choices for pneumonia. Influenza-associated mortality was unaffected by specialty.

Use of Saliva Swab for Detection of Influenza Virus in Patients Admitted to an Emergency Department

Nasopharyngeal (NP) specimens are commonly used for the detection of influenza, but saliva swabs are easier to obtain and cause less discomfort to the patients. The objective of this study was to evaluate the usefulness of saliva swab specimens for the diagnosis of influenza compared with NP specimens. Influenza virus detection rate in saliva and NP swabs was compared in adult patients admitted to an emergency department from January to March 2020, using the Xpert Xpress Flu/respiratory syncytial virus (RSV) test. Cycle threshold (C_T) values were evaluated in all the cases. Among the 82 patients recruited, 19 had an influenza-positive diagnostic test result (11 influenza A and 8 influenza B). Overall, the agreement between saliva and NP swabs results was 97.6% (80/82; κ = 0.929; 95% confidence interval [CI], 0.832 to 1.0). There was no significant difference in the influenza detection rate between saliva swab and NP specimens (20.7% [17/82] versus 23.2% [19/82]; P = 0.5). There were only two discordant results (influenza B in an NP and false negative in a saliva sample). Manual inspection of the amplification curves showed that influenza RNA had been amplified in saliva with high C_Ts (C_T of 40) that the test reported as a negative result. The overall sensitivity and specificity for saliva was 89.5% (73.0% to 100%) and 100% (99.2% to 100%), respectively. In all the cases, the same influenza virus (A/B) was detected. Median C_T values were significantly lower in NP (31; interquartile range [IQR], 21.0 to 32.0) than in saliva (33; IQR, 23.0 to 38.0) (P = 0.001) specimens. Saliva swabs have high sensitivity and specificity for the detection of influenza virus by the Xpert Xpress Flu/RSV test and a high overall agreement and C_T correlation with NP specimens. Saliva swab is a feasible specimen type for influenza testing that might be easily self-collected with minimal equipment and discomfort.

IMPORTANCE Early detection of influenza virus is important for guiding antiviral and antibacterial treatment for infection control and public health measures. We have observed that saliva swab specimens have high sensitivity and specificity for the detection of influenza by the Xpert Xpress Flu/respiratory syncytial virus (RSV) test and high overall agreement and C_T correlation with nasopharyngeal specimens. Saliva swab may therefore be a feasible specimen type for influenza testing that can be easily self-collected with minimal equipment and discomfort.

The ID NOW COVID-19, a high-speed high-performance assay

The ID NOW COVID-19 assay is a promising tool for the rapid identification of COVID-19 patients. However, its performances were questioned. We evaluate the ID NOW COVID-19 in comparison to a reference RT-PCR using a collection of 48 fresh nasopharyngeal swabs sampled on universal transport media (UTM). Only 2 false negatives of the ID NOW COVID-19 were identified. They display PCR cycle threshold values of 37.5 and 39.2. The positive percent agreement and the negative percent agreement were 94.9% and 100%, respectively. The Kappa value was 0.88. The ID NOW COVID-19 combines high-speed and accurate processing. Using UTM, the ID NOW COVID-19 could be repeated in the case of invalid result. Further analyses, such as screening of genetic variants or genome sequencing, could also be performed with the same sample. As for all tests, the results should be interpreted according to clinical and epidemiological context.

Comparative practicability and analytical performances of Credo VitaPCR™ Flu A&B and Cepheid Xpert® Xpress Flu/RSV platforms

To compare the practicability (usability and satisfaction) and analytical performances of VitaPCR™ Flu A&B Assay (Credo Diagnostics Biomedical Pte. Ltd., Singapore, Republic of Singapore) and Xpert® Xpress Flu/RSV kit (Cepheid, Sunnyvale, USA), two rapid point-of-care (POC) nucleic acid amplification tests (NAATs) by reference to multiplex RT-PCR for respiratory viruses. Nasopharyngeal swabs (n=117) were collected from patients with influenza-like illness in Paris, France. Thawed specimens were further analyzed with both NAATs. The usability was comparable for both NAATs. Satisfaction questionnaire was better for the VitaPCR™ platform for the short time of test result in 20 minutes. Both NAATs showed comparable sensitivities (VitaPCR^TM: 95.0%; Xpert® Xpress: 97.5%) and specificities (100%) for influenza A/B RNA detection, with excellent reliability and accuracy between both NAATs. Both VitaPCR™ and Xpert® Xpress NAATs can be implemented in hospital setting as POC NAATs to rapidly detect influenza A/B RNA in symptomatic patients.

Multiplex Molecular Point-of-Care Test for Syndromic Infectious Diseases

Point-of-care (POC) molecular diagnostics for clinical microbiology and virology has primarily focused on the detection of a single pathogen. More recently, it has transitioned into a comprehensive syndromic approach that employs multiplex capabilities, including the simultaneous detection of two or more pathogens. Multiplex POC tests provide higher accuracy to for actionable decisionmaking in critical care, which leads to pathogen-specific treatment and standardized usages of antibiotics that help prevent unnecessary processes. In addition, these tests can be simple enough to operate at the primary care level and in remote settings where there is no laboratory infrastructure. This review focuses on state-of-the-art multiplexed molecular point-of-care tests (POCT) for infectious diseases and efforts to overcome their limitations, especially related to inadequate throughput for the identification of syndromic diseases. We also discuss promising and imperative clinical POC approaches, as well as the possible hurdles of their practical applications as front-line diagnostic tests.

Does location of rapid influenza diagnostic testing influence treatment time and ancillary testing in a paediatric emergency department?

OBJECTIVE

Influenza causes a significant burden of disease. Our aim was to assess whether location of rapid influenza diagnostic testing (RIDT) for patients with influenza-like illness (ILI) has an impact on ED treatment time or ancillary testing.

METHODS

This was a retrospective observational study in a tertiary paediatric ED during 2017 influenza season. All patients with ILI were included. Some had RIDT performed (ED bedside or at the laboratory). Primary outcome measure was the correlation of RIDT location to treatment time compared to patients with ILI with no RIDT. Secondary outcome measures were the correlation of RIDT location to ancillary testing and treatment with antibiotics.

RESULTS

A total of 1451 patients with ILI were included. Eighty patients for whom RIDT was performed at the laboratory had a shorter treatment time in the ED when compared to the 215 patients for whom RIDT was performed bedside (2.8 and 3.4 h, respectively; P < 0.0001). However, treatment time was not statistically different when sub-analysed for admitted and discharged patients separately. Overall, patients with ILI and no RIDT had the shortest treatment time in the ED (1.7 h). There was no difference in ancillary testing and treatment with antibiotics between ILI patients for whom RIDT was performed bedside or at the laboratory regardless of admission.

CONCLUSION

Location of RIDT may not have a significant impact on treatment time, ancillary testing and treatment with antibiotics. When RIDT was not performed, patients had the shortest treatment time.

Portable and accurate diagnostics for COVID-19: Combined use of the miniPCR thermocycler and a well-plate reader for SARS-CoV-2 virus detection

The coronavirus disease 2019 (COVID-19) pandemic has crudely demonstrated the need for massive and rapid diagnostics. By the first week of July, more than 10,000,000 positive cases of COVID-19 have been reported worldwide, although this number could be greatly underestimated. In the case of an epidemic emergency, the first line of response should be based on commercially available and validated resources. Here, we demonstrate the use of the miniPCR, a commercial compact and portable PCR device recently available on the market, in combination with a commercial well-plate reader as a diagnostic system for detecting genetic material of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19. We used the miniPCR to detect and amplify SARS-CoV-2 DNA sequences using the sets of initiators recommended by the World Health Organization (WHO) for targeting three different regions that encode for the N protein. Prior to amplification, samples were combined with a DNA intercalating reagent (i.e., EvaGreen Dye). Sample fluorescence after amplification was then read using a commercial 96-well plate reader. This straightforward method allows the detection and amplification of SARS-CoV-2 nucleic acids in the range of ~625 to 2×105 DNA copies. The accuracy and simplicity of this diagnostics strategy may provide a cost-efficient and reliable alternative for COVID-19 pandemic testing, particularly in underdeveloped regions where RT-QPCR instrument availability may be limited. The portability, ease of use, and reproducibility of the miniPCR makes it a reliable alternative for deployment in point-of-care SARS-CoV-2 detection efforts during pandemics.

The impact of point-of-care testing for influenza A and B on patient flow and management in a medical assessment unit of a general hospital

Objectives

Timely implementation of influenza infection control and treatment can significantly reduce the impact on Hospital resources and patient management when demand is at peak. Turnaround times of Laboratory based screening tests for the diagnosis of influenza may have an impact on the implementation of infection control measures and treatment. In this study the objectives included determining the correlation between the Abbott ID NOW point-of-care testing (POCT) instrument using the Influenza A&B2 test and the laboratory based GeneXpert Flu+RSV kit. In addition the impact of the POCT instrument on the prescription of antivirals and antibiotics was evaluated by comparing with practice when the instrument was not in place.

Results

The results of the correlation study with a cohort of 54 patients revealed the Abbott ID NOW POCT has 92% sensitivity for the detection of Influenza A, while specificity was 100% for both Influenza A and B. The impact of the POCT instrument on the frequency of prescription of antivirals and amount of antibiotics consumed (33% reduction in antibiotic consumption in a cohort of 65 (2017) and 61 (2018)) was significant. In addition the average patient length of Hospital stay was significantly reduced from 5.26 days to 3.73 days.

Cost-Effective Respiratory Virus Testing

The timely and accurate diagnosis of respiratory virus infections has the potential to optimize downstream (posttesting) use of limited health care resources, including antibiotics, antivirals, ancillary testing, and inpatient and emergency department beds. Cost-effective algorithms for respiratory virus testing must take into consideration numerous factors, including which patients should be tested, what testing should be performed (for example, antigen testing versus reverse transcription-PCR testing or influenza A/B testing versus testing with a comprehensive respiratory virus panel), and the turnaround time necessary to achieve the desired posttesting outcomes. Despite the clinical impact of respiratory virus infections, the cost-effectiveness of respiratory virus testing is incompletely understood. In this article, we review the literature pertaining to the cost-effectiveness of respiratory virus testing in pediatric and adult patient populations, in emergency department, outpatient, and inpatient clinical settings. Furthermore, we consider the cost-effectiveness of a variety of testing methods, including rapid antigen tests, direct fluorescent antibody assays, and nucleic acid amplification tests.

Cost-Benefit Analysis of Real-Time Influenza Testing for Patients in German Emergency Rooms

Background: Seasonal influenza causes significant morbidity worldwide and has a substantial economic impact on the healthcare system. Objective: To assess the cost–benefit relation of implementing a real-time influenza test in emergency rooms (ER) of German hospitals. Methods: A deterministic decision-analytic model was developed simulating the incremental costs of using the Solana^® Influenza A+B test, compared to those of using conventional clinical judgement alone to confirm or exclude influenza in adult ILI (influenza-like illness) patients, in German ER, prior to hospitalization. Direct costs were evaluated from the hospital perspective, considering resource use directly related to influenza testing and treatment, as well as indirect costs incurred by nosocomial influenza transmission. Results: Through base-case analysis and assuming an influenza prevalence of 42.6%, real-time testing with Solana^® reduced average costs of hospitalized ILI patients by €132.61, per tested patient. Moreover, the Solana^® saved €6.9 per tested patient in favor of the hospital. In probabilistic sensitivity analysis, under all reasonable assumptions, implementing the Solana^® saved on average €144.13 as compared to applying the clinical-judgement-only strategy, thus, it was found to be constantly less expensive. Conclusions: Using highly sensitive and specific real-time influenza tests in ILI patients at German ER might significantly reduce hospital expenditures

Is there a clinical difference between influenza A and B virus infections in hospitalized patients? : Results after routine polymerase chain reaction point-of-care testing in the emergency room from 2017/2018

PURPOSE

The clinical presentation, complications and mortality in molecularly confirmed influenza A and B infections were analyzed.

METHODS

This retrospective observational single-centre study included all influenza positive patients older than 18 years who were hospitalized and treated at the flu isolation ward during 2017/2018. The diagnosis was based on point-of-care tests with the Alere^TM.

RESULTS

Of the 396 patients tested positive for influenza, 24.2% had influenza A and 75.8% influenza B. Influenza A patients were younger (median age 67.5 years vs. 77 years, p < 0.001), were more often smokers (27.7% vs. 16.8%, p = 0.021), had chronic pulmonary diseases more frequently (39.6% vs. 26.3%, p = 0.013), presented with a higher body temperature (38.6 °C vs. 38.3 °C, p = 0.004), leucocyte count (8 G/L vs. 6.8 G/L, p = 0.002), C‑reactive protein (CRP) level (41 mg/l vs. 23 mg/l, p < 0.001) and had dyspnea more often (41.7% vs. 28%, p = 0.012). Influenza B patients had an underlying chronic kidney disease in 37% vs. 18.8% (p < 0.001) and presented with vomiting on admission more frequently (21.7% vs. 11.5%, p = 0.027). Influenza A patients were admitted for 8 days vs. 7 days (p = 0.023). There were no differences in the rate of complications; however, 22 (5.6%) patients died during the hospital stay. The in-hospital mortality was higher in influenza A patients (8.3% vs 4.7%, p = 0.172).

CONCLUSION

Some differences were found between influenza A and B virus infections but symptoms were overlapping, which necessitates polymerase chain reaction point-of-care testing for accurate diagnosis. Influenza A was a more severe disease than influenza B during the period 2017/2018.

Influenza virus infection: an approach to identify predictors for in-hospital and 90-day mortality from patients in Vienna during the season 2017/18

BACKGROUND

Seasonal influenza outbreaks are associated with increased mortality and hospitalisation rates. Herein we tried to identify predictors of mortality in hospitalised patients with influenza virus infection.

MATERIALS/METHODS

In this exploratory retrospective observational single-centre-study we included all influenza-positive patients older than 18 years who were hospitalised and treated at the flu-isolation-ward during the influenza season 2017/18. Diagnosis was based on point-of-care-test with the Alere™ i. First we performed χ² tests and Mann-Whitney U tests to identify predictors of mortality. Significant variables were used in a stepwise-forward-logistic-regression-model to predict in-hospital and 90-day mortality.

RESULTS

Of the 396 patients who tested positive for influenza 96 (24.2%) had influenza A and 300 (75.8%) influenza B. Twenty-two (5.6%) died in hospital and the 90-day mortality rate was 9.4%. In the stepwise logistic regression older age (OR 1.1 per year 95% CI 1.03-1.17), history of atrial fibrillation (OR 5.91 95% CI 1.91-18.34), dementia (OR 3.98 95% CI 1.24-12.78), leucocyte count (OR 1.11 per G/L 95% CI 1.03-1.20), pneumonia (OR 4.39 95% CI 1.44-13.39) and acute heart failure (OR 23.15 95% CI 4.33-123.76) increased the risk of in-hospital mortality. The risk for 90-day mortality was increased by older age (OR 1.04 per year 95% CI 1.01-1.07), history of atrial fibrillation (OR 3.1, 95% CI 1.36-7.05), history of congestive heart failure (OR 4.7 95% CI 1.94-11.48), pneumonia (OR 3.2 95% CI 1.45-6.91) and decreased by statin use (OR 0.28 95% CI 0.10-0.78).

CONCLUSIONS

Older age, history of atrial fibrillation and pneumonia are associated with increased risk of influenza-associated in-hospital and 90-day mortality. Statin use may decrease 90-day mortality.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

An optimized molecular method for detection of influenza A virus using improved generic primers and concentration of the viral genomic RNA and nucleoprotein complex

For reported primer sets used to detect influenza A viruses (IAVs), we verified the nucleotide identities with 9,103 complete sequences of matrix (M) genes. At best, only 93.2% and 85.3% of the sequences had a 100% match with reported forward and reverse primers, respectively. Therefore, we designed new degenerate forward and reverse primers with 100% identity to 94.4% and 96.2% of compared genes, respectively, and the primer set was used with SYBR-based reverse-transcription real-time PCR (SYBR-RT-rtPCR) for lower detection limits. The sensitivity of SYBR-RT-rtPCR with the new primers was 10-fold higher than that with a conventional method in ~2.37% of all M genes in the database used in our study. We successfully increased the sensitivity of SYBR-RT-rtPCR by concentrating the viral ribonucleoprotein (RNP) using immunomagnetic beads and Triton X-100. The improved generic primer set and RNP concentration method may be useful for sensitive detection of IAVs.

Prospective evaluation of three rapid molecular tests for seasonal influenza in patients presenting at an emergency unit

BACKGROUND

For infection control measures, rapid accurate diagnostics on admission of patients with suspected seasonal influenza is crucial.

OBJECTIVE

Prospective comparison of three rapid molecular tests for detection of influenza A/B RNA.

STUDY DESIGN

Outpatients presenting at the Medical emergency department of Graz University Hospital with influenza-like illness and a requirement for hospitalization (n = 312) were studied. Nasopharyngeal swabs were collected with the 3 mL-version of the UTM™ Viral Transport Medium (Copan). Specimens were tested for influenza A and B RNA using the Alere™ i Influenza A & B (Abbott), the cobas^® Influenza A/B (Roche), and the Xpert^® Xpress Flu/RSV (Cepheid) tests. Results were compared to those obtained from the same specimen by the Influenza A/B R-GENE^® (bioMerieux) test based on real-time PCR as reference method.

RESULTS

Overall sensitivities of the Abbott, Roche, and Cepheid tests were 90.5%, 96.0%, and 97.0%, overall specificities 99.4%, 97.6%, and 98.2% respectively. With the Abbott and the Cepheid tests, all specimens gave valid results, while the Roche test showed invalid results in 37 (12.1%) specimens. Total time to result for the Abbott, Roche, and Cepheid tests was 18 min, 22 min, and 32 min respectively.

CONCLUSIONS

The Abbott test lacked sensitivity, the Roche test was impaired by a high number of invalid results. Overall, despite the longest total time to result, the Cepheid test showed the best performance to detect influenza virus RNA in symptomatic patients presenting at an emergency unit in this study.

Economic and operational impact of an improved pathway using rapid molecular diagnostic testing for patients with influenza-like illness in a German emergency department

To evaluate the economic and operational effects of implementing a shorted diagnostic pathway during influenza epidemics. This retrospective study used emergency department (ED) data from the 2014/2015 influenza season. Alere i influenza A & B rapid molecular diagnostic test (RDT) was compared with the polymerase chain reaction (PCR) pathway. Differences in room occupancy time in the ED and inpatient ward and cost differences were calculated for the 14-week influenza season. The process flow was more streamlined with the RDT pathway, and the necessary isolation time in the ED was 9 h lower than for PCR. The difference in the ED examination room occupancy time was 2.9 h per patient on a weekday and 4 h per patient on a weekend day, and the difference in the inpatient room occupancy time was 2 h per patient on a weekday and 3 h per patient on a weekend day. Extrapolated time differences across the influenza season were projected to be 2733 h in the ED examination room occupancy and 1440 h in inpatient room occupancy. In patients with a negative diagnosis, the RDT was also estimated to reduce the total diagnostic costs by 41.52 € per patient compared with PCR. The total cost difference was projected to be 31,892 € across a 14-week influenza season. The improved process and earlier diagnosis with the RDT pathway compared with conventional PCR resulted in considerable savings in ED, inpatient room occupancy time and cost across the influenza season.

Detection Methods of Human and Animal Influenza Virus-Current Trends

The basic affairs connected to the influenza virus were reviewed in the article, highlighting the newest trends in its diagnostic methods. Awareness of the threat of influenza arises from its ability to spread and cause a pandemic. The undiagnosed and untreated viral infection can have a fatal effect on humans. Thus, the early detection seems pivotal for an accurate treatment, when vaccines and other contemporary prevention methods are not faultless. Public health is being attacked with influenza containing new genes from a genetic assortment between animals and humankind. Unfortunately, the population does not have immunity for mutant genes and is attacked in every viral outbreak season. For these reasons, fast and accurate devices are in high demand. As currently used methods like Rapid Influenza Diagnostic Tests lack specificity, time and cost-savings, new methods are being developed. In the article, various novel detection methods, such as electrical and optical were compared. Different viral elements used as detection targets and analysis parameters, such as sensitivity and specificity, were presented and discussed.

Profile of the Alere i Influenza A & B assay: a pioneering molecular point-of-care test

INTRODUCTION

The Alere i Influenza A & B assay incorporates the Nicking Enzyme Amplification Reaction technique on the Alere i instrument to detect and differentiate influenza virus (Flu) A and B nucleic acids in specific specimens. Areas covered: The Alere i Influenza A & B assay was cleared by the US Food and Drug Administration for use with nasal swabs (NS) and nasopharyngeal swabs, either directly or in viral transport medium. Notably, direct use on NS was the first ever CLIA-waived nucleic acid-based test. Previously published evaluations have reported sensitivities and specificities of 55.2-100% and 62.5-100% for Flu A and 45.2-100% and 53.6-100% for Flu B, respectively. Expert commentary: The Alere i Influenza A & B assay provides a rapid and simple platform for detection and differentiation of Flu A and B. Efforts are expected to further improve sensitivity and user-friendliness for effective and widespread use in the true point-of-care setting.

Accurate PCR Detection of Influenza A/B and Respiratory Syncytial Viruses by Use of Cepheid Xpert Flu+RSV Xpress Assay in Point-of-Care Settings: Comparison to Prodesse ProFlu

The Xpert Flu+RSV Xpress Assay is a fast, automated in vitro diagnostic test for qualitative detection and differentiation of influenza A and B viruses and respiratory syncytial virus (RSV) performed on the Cepheid GeneXpert Xpress System. The objective of this study was to establish performance characteristics of the Xpert Flu+RSV Xpress Assay compared to those of the Prodesse ProFlu+ real-time reverse transcription-PCR (RT-PCR) assay (ProFlu+) for the detection of influenza A and B viruses as well as RSV in a Clinical Laboratory Improvement Amendments (CLIA)-waived (CW) setting. Overall, the assay, using fresh and frozen nasopharyngeal (NP) swabs, demonstrated high concordance with results of the ProFlu+ assay in the combined CW and non-CW settings with positive percent agreements (PPA) (100%, 100%, and 97.1%) and negative percent agreements (NPA) (95.2%, 99.5%, and 99.6%) for influenza A and B viruses and RSV, respectively. In conclusion, this multicenter study using the Cepheid Xpert Flu+RSV Xpress Assay demonstrated high sensitivities and specificities for influenza A and B viruses and RSV in ∼60 min for use at the point-of-care in the CW setting.

Cost implications for the NHS of using the Alere™ i Influenza A & B near patient test with nasal swabs

BACKGROUND

Influenza is an acute viral infection of the respiratory tract. A rapid confirmatory diagnosis of influenza is important, since it is highly transmissible and outbreaks of influenza within the hospital setting increase morbidity and mortality. The objective of this study was to evaluate the cost implications, from the perspective of the UK NHS, of using on-label nasal swabs with the Alere™ i Influenza A & B test in a near patient setting.

METHODS

A cost consequence model was developed. The time horizon of the model was from hospital admission on suspicion of influenza until the end of treatment (following a diagnosis of influenza or discharge from hospital). Data on the prevalence of influenza and the sensitivity and specificity of the Alere™ i Influenza A & B test came from two prospective observational diagnostic accuracy studies. Costs were obtained from published resources. Uncertainties in the model data were investigated using deterministic, one-way sensitivity analyses.

RESULTS

Using the Alere™ i Influenza A & B point of care test with nasal swabs (on label) in NHS medical assessment units and emergency departments could save approximately £242,730 per 1000 adults presenting with influenza-like symptoms. The main cause for this was reduced times to availability of the result compared with the laboratory RT-PCR test. Other key drivers of savings were the cost of isolation, the prevalence of influenza, the specificity of the test, and the availability of isolation resources.

CONCLUSIONS

The Alere™ i Influenza A & B point of care test would have greatest impact in hospitals that have extensive delays in the time to receive a result. Sensitivity analyses identified the model parameters which would have greatest effect on the result and confirmed that assumptions were conservative, i.e. did not change key results.

Infectious diseases

The measurement of biochemical parameters such as blood glucose, blood gases, electrolytes and cardiac markers have particularly benefited from recent advances in POCT. More and more, this form of analysis is now positively impacting the field of infectious diseases. Many microbiological POCT systems tend to be designed as rapid tests. In general, such tests can be carried out in a few simple steps by medical assistants or physicians without laboratory equipment or laboratory experience. It is even possible for the patients themselves to perform a series of such tests.

Implementation of Alere i Influenza A & B point of care test for the diagnosis of influenza in an ED

STUDY OBJECTIVE

This study aimed to evaluate the impact of implementing rapid point-of-care testing (POCT) with the Alere i Influenza A & B in an emergency department (ED) during an influenza epidemic.

METHODS

Direct nasal swabs were prospectively collected following the physical examination of patients aged >18years who presented to the ED of a tertiary hospital in France with influenza-like illness (ILI) symptoms (N=301) between February 1st and March 31st, 2016, which coincided with an influenza epidemic. Laboratory-based testing (standard of care) was used to obtain a diagnosis in February 2016 (pre-POCT cohort) and positive results were confirmed using polymerase chain reaction. The primary endpoint was patient time in the ED.

RESULTS

A total of 169 and 132 patients participated in the pre-POCT phase and POCT phase respectively. A significantly higher proportion of patients received a positive diagnosis in the POCT cohort compared with the pre-POCT cohort (31% versus 5.3%, P<0.01). Mean time spent in the ED and hospitalization rate were significantly lower in the POCT cohort (6.06h versus 4.15h, P=0.03, and 44.4% versus 9.7%, P=0.02, respectively). Despite similar rates in the prescription of antibiotics and antiviral therapies, the proportion of patients who were referred for additional tests was significantly lower in the POCT cohort (78.1% versus 62.1%, P=0.003, and 80.5% versus 63.6%, P=0.01, respectively).

CONCLUSIONS

The Alere i Influenza A & B POCT reduced the length of stay in ED, the hospitalization rates, and the number of additional diagnostic tests compared with standard of care testing.

Diagnostic accuracy of the real-time PCR cobas® Liat® Influenza A/B assay and the Alere i Influenza A&B NEAR isothermal nucleic acid amplification assay for the detection of influenza using adult nasopharyngeal specimens

BACKGROUND

Accurate detection of influenza requires diagnostic testing; however, methods such as RADTs and central laboratory-based tests are limited by low sensitivity and time constraints, respectively.

OBJECTIVE

To compare the performances of the cobas^® Liat^® Influenza A/B and Alere™ i Influenza A&B point-of-care (POC) assays for detecting influenza A and B viruses using fresh nasopharyngeal specimens with the GenMark Dx^® Respiratory Viral Panel as the reference method, a FDA cleared IVD PCR test.

STUDY DESIGN

A total of 87 samples collected in viral transport medium from adults ≥18 years of age were re-tested on both POC assays (based on the reference PCR method, 29 were influenza A and 18 were influenza B virus positive).

RESULTS

The overall sensitivity and specificity of the cobas Influenza A/B for the detection of influenza A and B relative to reference PCR was 97.9% (95% confidence interval [CI] 88.9%, 99.6%) and 97.5% (95% CI: 87.1%, 99.6%), respectively, while the sensitivity of the Alere i Influenza A&B assay relative to the reference PCR method was 63.8% (95% CI: 49.5%, 76.0%) and the specificity was 97.5% (95% CI: 87.1%, 99.6%). The individual sensitivities and specificities of the cobas Influenza A/B assay for influenza A alone and influenza B alone were comparable to those of the reference PCR method (influenza A: sensitivity of 100% [95% CI: 88.3%, 100.0%] and specificity of 98.3% [95% CI: 90.9%, 99.7%]; influenza B: sensitivity of 94.4% [95% CI: 74.2%, 99.0%] and specificity of 100% [95% CI: 94.7%, 100.0%]). For the Alere i Influenza A&B assay, the individual specificities for influenza A and B were comparable to those of the reference PCR method (98.3% [95% CI: 90.9%, 99.7%] and 97.1% [95% CI: 90.0%, 99.2%], respectively), while the individual sensitivities were low relative to reference PCR (55.2% [95% CI: 37.5%, 71.6%] and 72.2% [95% CI: 49.1%, 87.5%], respectively).

CONCLUSION

The cobas Influenza A/B assay demonstrated performance equivalent to laboratory-based PCR, and could replace rapid antigen tests.

Respiratory RNA Viruses

Acute upper and lower respiratory infections are a major public health problem and a leading cause of morbidity and mortality worldwide. At greatest risk are young children, the elderly, the chronically ill, and those with suppressed or compromised immune systems. Viruses are the predominant cause of respiratory tract illnesses and include RNA viruses such as respiratory syncytial virus, influenza virus, parainfluenza virus, metapneumovirus, rhinovirus, and coronavirus. Laboratory testing is required for a reliable diagnosis of viral respiratory infections, as a clinical diagnosis can be difficult since signs and symptoms are often overlapping and not specific for any one virus. Recent advances in technology have resulted in the development of newer diagnostic assays that offer great promise for rapid and accurate detection of respiratory viral infections. This chapter emphasizes the fundamental characteristics and clinical importance of the various RNA viruses that cause upper and lower respiratory tract diseases in the immunocompromised host. It highlights the laboratory methods that can be used to make a rapid and definitive diagnosis for the greatest impact on the care and management of ill patients, and the prevention and control of hospital-acquired infections and community outbreaks.

Diagnostic accuracy and cost analysis of the Alere™ i Influenza A&B near-patient test using throat swabs

BACKGROUND

Clinical diagnostic sensitivity alone is inadequate in the diagnosis of influenza. Polymerase chain reaction (PCR) testing is sensitive but the inherent delays in result availability potentially prolong time to isolation and treatment. Until recently no near-patient test (NPT) has demonstrated adequate sensitivity for routine clinical use.

AIM

To evaluate diagnostic accuracy, time to result availability, clinical impact, and cost consequences of Alere™ i Influenza A&B NPT (Alere Inc., Waltham, MA, USA) using off-label throat swabs.

METHODS

Prospective, multi-centre [four UK National Health Service (NHS) hospitals], diagnostic accuracy cohort study with cost modelling. Throat swab samples from suspected influenza patients were tested for influenza using the reference standard of PCR; a second throat swab was tested using NPT.

FINDINGS

A total of 827 participants were recruited; 589 were suitable for analysis: sensitivity was 75.8% [95% confidence interval (CI): 67.0-84.6]; specificity was 96.8% (95% CI: 95.2-98.3). Sensitivity varied between Sheffield (Northern General Hospital: 82.1%; Royal Hallamshire Hospital: 83.3%) and other sites (Doncaster Royal Infirmary: 71.4%; Newcastle's Royal Victoria Infirmary: 50.0%) whereas specificity was high (92-100%). Positive predictive value (PPV) was 81.2% (95% CI: 72.9-89.5) with negative predictive value 95.6% (95% CI: 93.9-97.4) with observed prevalence of 15.4%. Median time to result for PCR was 1.1 days (on-site laboratories) and 5.2 days (remote laboratories). Isolation findings: 75% influenza positive not isolated; 69% of isolated participants did not have influenza. For a cohort of 1000 participants, annual estimated non-diagnostic cost savings with NPT are £215,040.

CONCLUSION

This first prospective study of the Alere i NPT using throat swabs demonstrates high specificity, high PPV during seasonal epidemics, and rapid result availability which could lead to substantial cost savings.

Evaluation of Alere i RSV for Rapid Detection of Respiratory Syncytial Virus in Children Hospitalized with Acute Respiratory Tract Infection

Alere i RSV is a novel rapid test which applies a nicking enzyme amplification reaction to detect respiratory syncytial virus in point-of-care settings. In this study, we evaluated the Alere i RSV assay by using frozen nasopharyngeal swab samples that were collected in viral transport medium from children hospitalized with acute respiratory tract infection during the 2015-2016 winter season. Alere i RSV assay results were compared to those for Altona RealStar RSV real-time reverse transcription-PCR (RT-PCR). We found that the overall sensitivity and specificity of the Alere i RSV test was 100% (95% confidence intervals [CI], 93% to 100%) and 97% (95% CI, 89% to 100%), respectively. Positive samples were identified within 5 to 7 min from sample collection. Overall, the Alere i RSV test performed well compared to the RT-PCR assay and has the potential to facilitate the detection of RSV in point-of-care settings.

New Developments in Clinical Bacteriology Laboratories

There are a number of changes underway in modern clinical bacteriology laboratories. Panel-based molecular diagnostics are now available for numerous applications, including, but not limited to, detection of bacteria and select antibacterial resistance markers in positive blood culture bottles, detection of acute gastroenteritis pathogens in stool, and detection of selected causes of acute meningitis and encephalitis in the cerebrospinal fluid. Today, rapid point-of-care nucleic acid amplification tests are bringing the accuracy of sophisticated molecular diagnostics closer to patients. A proteomic technology, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, is enabling rapid, accurate, and cost-effective identification of bacteria, as well as fungi, recovered in cultures. Laboratory automation, common in chemistry laboratories, is now available for clinical bacteriology laboratories. Finally, there are several technologies under development, such as rapid phenotypic antimicrobial susceptibility testing, whole-genome sequencing, and metagenomic analysis for the detection of bacteria in clinical specimens. It is helpful for clinicians to be aware of the pace of new development in their bacteriology laboratory to enable appropriate test ordering, to enable test interpretation, and to work with their laboratories and antimicrobial stewardship programs to ensure that new technology is implemented to optimally improve patient care.

Direct Comparison of Alere i and cobas Liat Influenza A and B Tests for Rapid Detection of Influenza Virus Infection

We compared two rapid, point-of care nucleic acid amplification tests for detection of influenza A and B viruses (Alere i [Alere] and cobas Liat [Roche Diagnostics]) with the influenza A and B virus test components of the FilmArray respiratory panel (BioFire Diagnostics) using 129 respiratory specimens collected in universal viral transport medium (80 influenza A virus and 16 influenza B virus positive) from both adult and pediatric patients. The sensitivities of the Alere test were 71.3% for influenza A virus and 93.3% for influenza B virus, with specificities of 100% for both viruses. The sensitivities and specificities of the Liat test were 100% for both influenza A and B viruses. The poor sensitivity of the Alere test for detection of influenza A virus was likely due to a study set that included many low-positive samples that were below its limit of detection.