BTA stat®, NMP22® BladderChek®, UBC® Rapid Test, and CancerCheck® UBC® rapid VISUAL as urinary marker for bladder cancer: Final results of a German multicenter study

INTRODUCTION AND OBJECTIVE

BTA stat®, NMP22® BladderChek®, UBC® Rapid Test, and CancerCheck® UBC® rapid VISUAL are urinary-based rapid tests. This multicenter study is the first study comparing all available rapid tests on a large cohort of bladder cancer patients and healthy controls in one setting.

METHODS

In total 732 urine samples (second morning urine) in a real-world assessment have been analyzed. We evaluated clinical samples from 464 patients with histologically confirmed urothelial tumors of the urinary bladder (17 solitary CIS, 189 low-grade, 187 high-grade nonmuscle invasive, 71 high-grade muscle invasive), 77 patients with No Evidence of Disease (NED), and from 191 healthy controls. Urine samples were analyzed by the BTA stat®, NMP22® BladderChek®, UBC® Rapid Test point-of-care (POC) system using the concile Omega 100 POC reader, and CancerCheck® UBC® rapid VISUAL. Sensitivities and specificities were calculated by contingency analyses.

RESULTS

All investigated urinary markers detected more pathological concentrations in urine of bladder cancer patients compared to tumor-free patients. The calculated diagnostic sensitivities for BTA stat®, NMP22® BladderChek®, UBC® Rapid Test, CancerCheck® UBC® rapid VISUAL, and cytology were 62.4%, 13.4%, 58.2%, 28.6%, 36.2% for low-grade, 83.4%, 49.5%, 84.5%, 63.1%, 71.2% for high-grade nonmuscle invasive, and 95.8%, 35.2%, 76.1%, 50.7%, 67.7% for high-grade muscle-invasive bladder cancer. The specificity was 67.9%, 95.5%, 79.4%, 94.4%, and 83.7%, respectively. The area under the curve (AUC) after receiver operating characteristics (ROC) analysis for high-grade non-muscle-invasive tumors was 0.757, 0.725, 0.819, 0.787, and 0.774, respectively.

CONCLUSIONS

The analysis of more than 700 urine samples offers an objective view on urine-based rapid diagnostics. Elevated pathological concentrations of markers in urine of bladder cancer patients were detected in all investigated tests. The highest sensitivities for high-grade non-muscle-invasive tumors were calculated for BTA stat® and UBC® Rapid Test, whereas NMP22® BladderChek®, and cytology showed the highest specificities. BTA stat® and UBC® Rapid Test have the potential to be used as a clinical valuable urinary protein biomarker for the detection of high-grade non-muscle-invasive bladder cancer patients and could be included in the management of these tumors.

Rapid antigen-based and rapid molecular tests for the detection of SARS-CoV-2: a rapid review with network meta-analysis of diagnostic test accuracy studies

BACKGROUND

The global spread of COVID-19 created an explosion in rapid tests with results in < 1 hour, but their relative performance characteristics are not fully understood yet. Our aim was to determine the most sensitive and specific rapid test for the diagnosis of SARS-CoV-2.

METHODS

Design: Rapid review and diagnostic test accuracy network meta-analysis (DTA-NMA).

ELIGIBILITY CRITERIA

Randomized controlled trials (RCTs) and observational studies assessing rapid antigen and/or rapid molecular test(s) to detect SARS-CoV-2 in participants of any age, suspected or not with SARS-CoV-2 infection.

INFORMATION SOURCES

Embase, MEDLINE, and Cochrane Central Register of Controlled Trials, up to September 12, 2021.

OUTCOME MEASURES

Sensitivity and specificity of rapid antigen and molecular tests suitable for detecting SARS-CoV-2. Data extraction and risk of bias assessment: Screening of literature search results was conducted by one reviewer; data abstraction was completed by one reviewer and independently verified by a second reviewer. Risk of bias was not assessed in the included studies.

DATA SYNTHESIS

Random-effects meta-analysis and DTA-NMA.

RESULTS

We included 93 studies (reported in 88 articles) relating to 36 rapid antigen tests in 104,961 participants and 23 rapid molecular tests in 10,449 participants. Overall, rapid antigen tests had a sensitivity of 0.75 (95% confidence interval 0.70-0.79) and specificity of 0.99 (0.98-0.99). Rapid antigen test sensitivity was higher when nasal or combined samples (e.g., combinations of nose, throat, mouth, or saliva samples) were used, but lower when nasopharyngeal samples were used, and in those classified as asymptomatic at the time of testing. Rapid molecular tests may result in fewer false negatives than rapid antigen tests (sensitivity: 0.93, 0.88-0.96; specificity: 0.98, 0.97-0.99). The tests with the highest sensitivity and specificity estimates were the Xpert Xpress rapid molecular test by Cepheid (sensitivity: 0.99, 0.83-1.00; specificity: 0.97, 0.69-1.00) among the 23 commercial rapid molecular tests and the COVID-VIRO test by AAZ-LMB (sensitivity: 0.93, 0.48-0.99; specificity: 0.98, 0.44-1.00) among the 36 rapid antigen tests we examined.

CONCLUSIONS

Rapid molecular tests were associated with both high sensitivity and specificity, while rapid antigen tests were mainly associated with high specificity, according to the minimum performance requirements by WHO and Health Canada. Our rapid review was limited to English, peer-reviewed published results of commercial tests, and study risk of bias was not assessed. A full systematic review is required.

REVIEW REGISTRATION

PROSPERO CRD42021289712.

Temporal discrepancies in "rapid" HIV testing: explaining misdiagnoses at the point-of-care in Zimbabwe

BACKGROUND

Rapid diagnostic tests have revolutionized the HIV response in low resource and high HIV prevalence settings. However, disconcerting levels of misdiagnosis at the point-of-care call for research into their root causes. As rapid HIV tests are technologies that cross borders and have inscribed within them assumptions about the context of implementation, we set out to explore the (mis)match between intended and actual HIV testing practices in Zimbabwe.

METHODS

We examined actual HIV testing practices through participant observations in four health facilities and interviews with 28 rapid HIV testers. As time was identified as a key sphere of influence in thematic analyses of the qualitative data, a further layer of analysis juxtaposed intended (as scripted in operating procedures) and actual HIV testing practices from a temporal perspective.

RESULTS

We uncover substantial discrepancies between the temporal flows assumed and inscribed into rapid HIV test kits (their intended use) and those presented by the high frequency testing and low resource and staffing realities of healthcare settings in Zimbabwe. Aside from pointing to temporal root causes of misdiagnosis, such as the premature reading of test results, our findings indicate that the rapidity of rapid diagnostic technologies is contingent on a slow, steady, and controlled environment. This not only adds a different dimension to the meaning of "rapid" HIV testing, but suggests that errors are embedded in the design of the diagnostic tests and testing strategies from the outset, by inscribing unrealistic assumptions about the context within which they used.

CONCLUSION

Temporal analyses can usefully uncover difficulties in attuning rapid diagnostic test technologies to local contexts. Such insight can help explain potential misdiagnosis 'crisis points' in point-of-care testing, and the need for public health initiatives to identify and challenge the underlying temporal root causes of misdiagnosis.

Research on point-of-care tests in outpatient care in Germany: A scoping review and definition of relevant endpoints in evaluation studies

BACKGROUND

The fast turnaround time and user-friendliness of point-of-care tests (POCTs) offer a great potential to improve outpatient health care where clinical decisions have to be made during the physician-patient encounter and time resources are limited. The aim of this scoping review is to describe the extent and nature as well as gaps in German research activities on POCT in outpatient care. In addition, we define research endpoints that should be addressed in the comprehensive evaluation of POCTs targeted for outpatient care.

METHODS

We performed a scoping review with a systematic literature search in Medline (via PubMed), Scopus, Web of Science, Cochrane library and Google Scholar for German publications on POCT with relevance to German outpatient care published from January 2005 to November 2020.

RESULTS

Our literature search identified 2,200 unique records. After literature selection 117 articles were included in this scoping review. Just over half of the articles (67/117, 57.3%) were primary research studies with original data, while one third of all the studies (33.3%) were secondary research articles (e.g., review articles). The remaining articles were clinical recommendations / position papers (7/117, 6.0%) and other types of articles (3.4%). The majority of articles focused on POCT use in infectious diseases (44/117, 37.6%), diabetic syndromes (15.4%), cardiac disease (12.0%) or coagulopathies and thrombosis (10.3%), while the remaining articles did not specify the disease (13.7%) or investigated other diseases (11.1%). Similar to international studies, most primary research studies investigated the diagnostic performance of POCT (e.g., sensitivity, specificity). Evidence beyond diagnostic accuracy remains scarce, such as the impact on therapeutic decisions and practice routines, clinical effectiveness, and user perspectives. In line with this, interventional studies (such as RCTs) on the effectiveness of POCT use in German outpatient care are limited. We define six endpoint domains that should be addressed in the evaluation of POCTs targeted for outpatient care: (i) diagnostic performance, (ii) clinical performance, (iii) time and costs, (iv) impact on clinical routines / processes, (v) perspectives of medical professionals and patients, and (vi) broader aspects.

CONCLUSION

There is considerable research activity on POCTs targeted for use in outpatient care in Germany. Data on their potential benefits beyond diagnostic accuracy is often lacking and should be addressed in future POCT research studies.

Diagnosing Tuberculosis: What Do New Technologies Allow Us to (Not) Do?

New tuberculosis (TB) diagnostics are at a crossroads: their development, evaluation, and implementation is severely damaged by resource diversion due to COVID-19. Yet several technologies, especially those with potential for non-invasive non-sputum-based testing, hold promise for efficiently triaging and rapidly confirming TB near point-of-care. Such tests are, however, progressing through the pipeline slowly and will take years to reach patients and health workers. Compellingly, such tests will create new opportunities for difficult-to-diagnose populations, including primary care attendees (all-comers in high burden settings irrespective of reason for presentation) and community members (with early stage disease or risk factors like HIV), many of whom cannot easily produce sputum. Critically, all upcoming technologies have limitations that implementers and health workers need to be cognizant of to ensure optimal deployment without undermining confidence in a technology that still offers improvements over the status quo. In this state-of-the-art review, we critically appraise such technologies for active pulmonary TB diagnosis. We highlight strengths, limitations, outstanding research questions, and how current and future tests could be used in the presence of these limitations and uncertainties. Among triage tests, CRP (for which commercial near point-of-care devices exist) and computer-aided detection software with digital chest X-ray hold promise, together with late-stage blood-based assays that detect host and/or microbial biomarkers; however, aside from a handful of prototypes, the latter category has a shortage of promising late-stage alternatives. Furthermore, positive results from new triage tests may have utility in people without TB; however, their utility for informing diagnostic pathways for other diseases is under-researched (most sick people tested for TB do not have TB). For confirmatory tests, few true point-of-care options will be available soon; however, combining novel approaches like tongue swabs with established tests like Ultra have short-term promise but first require optimizations to specimen collection and processing procedures. Concerningly, no technologies yet have compelling evidence of meeting the World Health Organization optimal target product profile performance criteria, especially for important operational criteria crucial for field deployment. This is alarming as the target product profile criteria are themselves almost a decade old and require urgent revision, especially to cater for technologies made prominent by the COVID-19 diagnostic response (e.g., at-home testing and connectivity solutions). Throughout the review, we underscore the importance of how target populations and settings affect test performance and how the criteria by which these tests should be judged vary by use case, including in active case finding. Lastly, we advocate for health workers and researchers to themselves be vocal proponents of the uptake of both new tests and those − already available tests that remain suboptimally utilized.

A compact, low-cost, and binary sensing (BiSense) platform for noise-free and self-validated impedimetric detection of COVID-19 infected patients

Electrochemical immuno-biosensors are one of the most promising approaches for accurate, rapid, and quantitative detection of protein biomarkers. The two-working electrode strip is employed for creating a self-supporting system, as a tool for self-validating the acquired results for added reliability. However, the realization of multiplex electrochemical point-of-care testing (ME-POCT) requires advancement in portable, rapid reading, easy-to-use, and low-cost multichannel potentiostat readers. The combined multiplex biosensor strips and multichannel readers allow for suppressing the possible complex matrix effect or ultra-sensitive detection of different protein biomarkers. Herein, a handheld binary-sensing (BiSense) bi-potentiostat was developed to perform electrochemical impedance spectroscopy (EIS)-based signal acquisition from a custom-designed dual-working-electrode immuno-biosensor. BiSense employs a commercially available microcontroller and out-of-shelf components, offering the cheapest yet accurate and reliable time-domain impedance analyzer. A specific electrical board design was developed and customized for impedance signal analysis of SARS-CoV-2 nucleocapsid (N)-protein biosensor in spiked samples and alpha variant clinical nasopharyngeal (NP) swab samples. BiSense showed limit-of-detection (LoD) down to 56 fg/mL for working electrode 1 (WE1) and 68 fg/mL for WE2 and reported with a dynamic detection range of 1 pg/mL to 10 ng/mL for detection of N-protein in spiked samples. The dual biosensing of N-protein in this work was used as a self-validation of the biosensor. The low-cost (∼USD$40) BiSense bi-potentiostat combined with the immuno-biosensors successfully detected COVID-19 infected patients in less than 10 min, with the BiSense reading period shorter than 1.5 min, demonstrating its potential for the realization of ME-POCTs for rapid and hand-held diagnosis of infections.

Evaluation of 32 rapid tests for detection of antibodies against SARS-CoV-2

AIMS

To evaluate the analytical performance of 32 rapid tests for detection of antibodies against coronavirus SARS-CoV-2.

MATERIALS AND METHODS

We used at total of 262 serum samples (197 pre-pandemic and 65 convalescent COVID-19), and three criteria to evaluate the rapid tests under standardized and optimal conditions: (i) Immunoglobulin G (IgG) specificity "good" if lower limit of the 95% confidence interval was ≥ 97.0%, "acceptable" if point estimate was ≥ 97.0%, otherwise "not acceptable". (ii) IgG sensitivity "good" if point estimate was ≥ 90.0%, "acceptable" if ≥ 85.0%, otherwise "not acceptable". (iii) User-friendliness "not acceptable" if complicated to perform or difficult to read result, otherwise "good". We also included partial evaluations of three automated immunoassay systems.

RESULTS

Sensitivity and specificity varied considerably; IgG specificity between 90.9% (85.9-94.2) and 100% (97.7-100.0), and IgG sensitivity between 53.8% (41.9-65.4) and 98.5% (91.0-100.0). Combining our evaluation criteria, none of the 28 rapid tests that detected IgG had an overall performance considered "good", seven tests were considered "acceptable", while 21 tests were considered "not acceptable". Four tests detected only total antibodies and were not given an overall evaluation. IgG sensitivity and/or specificity of the automated immunoassays did not exceed that of many rapid tests.

CONCLUSION

When prevalence is low, the most important analytical property is a test's IgG specificity, which must be high to minimize false positive results. Out of 32 rapid tests, none had a performance classified as "good", but seven were classified as "acceptable".

Paper based analytical devices for blood grouping: a comprehensive review

The clinical importance of blood group (BG) antigens is related to their ability to induce immune antibodies that can cause hemolysis. Yet, ABO and D (Rh) are still considered to be the key antigens for healthy blood transfusion and secondary antigens are the next priority. Serological typing is the most widely used typing method. Rapid and accurate blood grouping plays an important role in some clinical conditions, rather than conventional techniques. Hence, developing a simple and economical model for rapid blood grouping would facilitate these tests. In recent decades, paper-based microfluidics such as μPADs has gained much interest in wide application areas such as point-of-care diagnostic. In this study, we evaluated μPADs that are performed for blood grouping and its recent progress. A comprehensive literature search was performed using databases including PUBMED, SCOPUS, Web of Science and Google Scholar. Keywords were blood grouping or typing, paper analytical device, rapid test, etc. After investigation of search results, 16 papers from 2010 to 2020 were included. Further information in detail was classified in Table 1. Generally, two principles for blood typing μPADs are introduced. The lateral chromatographic flow method and the vertical flow-through method that detects BG in a visual-based manner. To detect results with acceptable clarity many factors and challenges like paper, blood sample, buffer, Ab and RBC interaction and also μPADs stability need to be considered, which are discussed. In conclusion, the simplicity, stability, cheapness, portability and biocompatibility of μPADs for blood grouping confirming its utility and also they have the capability to robust, universal blood-grouping platform. Table 1 Summary of blood grouping tests using paper-based analytical devices Antigens Type of diagnosis Validation method Sample No Accuracy Action time Paper type Stability Sample dilution Buffer Ref A, B, Rh Forward volunteers records 5 - - Whatman No. 4 - 1/2 PBS* (Khan et al. 2010) A, B, Rh Forward gel assay test and conventional slide test 100 100% 1 min Whatman No. 4 and Kleeenex paper towel 7 Days in 4 °C 1/1 NSS (Al-Tamimi et al. 2012) A, B, Rh Forward gel card assay 99 100% 20 Sec + Washing Kleeenex paper towel - 1/1 NSS (Li et al. 2012) A, B, Rh Forward - - - - Kleeenex paper towel - 45/100 PSS (Li et al. 2013) A, B, Rh Forward gel card assay 98 100% 1.5 min Kleeenex paper towel - 85/100 PBS (Guan et al. 2014b) C, E, c, e, K, Jka, Jkb, M, N, S, P1, and Lea Forward gel card assay 266 100% - Kleeenex paper towel - 1/1 NSS (Li et al. 2014b) A, B, Rh Forward and Reverse conventional slide test 96 ≈ 91% 10 min Whatman No. 1 21 Days in 4 °C 1/2 NSS (Noiphung et al. 2015) C, c, E, e, K, k, Fya, Fyb, Jka, Jkb, M, N, S and s, P1, Lea and Leb Forward - 478 - - Kleeenex paper towel - 1/1 NSS, PBS (Then et al. 2015) A, B Forward and Reverse conventional slide test 76 100% 5-8 min Whatman No. 4 38 Days in 4 °C 1/4, 1/1 NSS (Songjaroen and Laiwattanapaisal 2016) D, K Forward volunteers records 210 - 7.5 min Kleenex paper towel - 1/1 NSS (Yeow et al. 2016) A, B, c, e, D, C, E, M, N, S, s, P1, Jka, Jkb, Lea, Leb, Fya, and Fyb Forward and Reverse gel card assay 3550 ≈100% 30 s Fiber glass and cotton linter 180 Days in 25 °C 45/100, 1/1 PBS (Zhang et al. 2017) A, B Forward conventional slide test 598 100% 3 min Whatman No. 113 14 Day in 4 °C 1/1 NSS (Songjaroen et al. 2018) A, B, Rh Forward conventional slide test - - 30 Sec + Washing Unrefined sisal paper - 1/2 NSS (Casals-Terré et al. 2019) A, B, Rh Forward - - - - Whatman No.1 - 1/1 NSS (Ansari et al. 2020) ABO & Rh Forward and Reverse conventional slide test - 100% Unrefined Eucalyptus papers - 1/2 NSS, PBS (Casals-Terré et al. 2020) A, B, Rh Forward - - - 30 Sec + Washing Whatman No. 4 modified with chitosan  ≥ 100 days in 25 °C 1/1 NSS (Parween et al. 2020) ^*phosphate buffer saline, normal saline solution.

Evaluation of a strategy for identification of hepatitis C virus carriers in outpatient and emergency units: contribution to the microelimination of hepatitis C in Brazil

Introduction

Hepatitis C virus (HCV) infection continues to be an important public health problem worldwide. Despite the availability of drugs that promote the cure of infection in more than 95% of cases, the identification of HCV carriers remains a major challenge.

Objective

To evaluate a strategy for identifying HCV carriers based on combined criteria: screening in emergency units and specialty outpatient clinics of a tertiary hospital and among older adults (≥45 years), both suggested as efficient in epidemiological studies.

Methods

A cross-sectional, analytical and descriptive study was conducted on individuals of both sexes, aged 45 years and older, attending the emergency department and specialty outpatient clinics of a University Hospital in São Paulo, Brazil, from January 2016 to June 2018. After giving formal consent, the patients were submitted to a standardized interview and rapid testing for the identification of HCV antibodies (SD BIOLINE® anti-HCV).

Results

A total of 606 adult patients (62% women and 37% men) were evaluated. The mean age was 62 ± 10 years. Four positive tests were identified, with confirmation by conventional serology and HCV-RNA determination. Thus, the prevalence of HCV identified in the sample was 0.66%. All patients had a history of risk factors for infection.

Conclusion

The strategies of birth-cohort testing and screening in emergency medical services for the identification of HCV carries, both suggested in the literature as efficient for the diagnosis of hepatitis C, resulted in a low rate of HCV infection. These findings highlight the magnitude of the challenge of identifying asymptomatic HCV carriers in Brazil.

Combination of phenylboronic acid and oligocytosine for selective and specific detection of lead(ii) by lateral flow test strip

Detection of lead (II) in water sources is of high importance for protection from this toxic contaminant. This paper presents the development and approbation of a lateral flow test strip of lead (II) with the use of phenylboronic acid as chelating agent and oligocytosine chain as receptor for the formed complexes. To locate the bound lead (II) on the test strip, phenylboronic acid was conjugated with carrier protein (bovine serum albumin) and applied as a binding line. In turn, the oligocytosine was conjugated with gold nanoparticle to provide coloration of the finally formed complexes (bovine serum albumin - phenylboronic acid - lead (II) - oligocytosine - gold nanoparticle). This combination of two binding molecules provides the «sandwich » assay with direct dependence of label binding from the analyte content. The technique is characterized by high sensitivity (0.05 ng mL^-1) and the absence of cross-reactions with other metal ions which are often satellite in natural waters. The developed lateral flow tests were successfully applied for lead (II) detection in water. Time of the assay was 5 min. The reached parameters confirm efficiency of the proposed technique for rapid and non-laborious testing under nonlaboratory conditions.

[Evaluation of a public health program on early HIV diagnosis with quick test]

OBJECTIVE

The use of HIV planned and structured, community-based rapid tests is one of the main strategies for the early detection of HIV infection. The objective of the study was to assess the HIV early diagnosis programme with rapid test in the Region of Murcia.

METHODS

Descriptive analysis of the programme users' epidemiological data during the years 2016 to 2018. Variables related to sociodemographic characteristics, risk exposure, history of HIV test performance and its result were analyzed. All analyzes were performed with statistical software IBM SPSS25 and Microsoft Excel version 2013. Frequencies were calculated in absolute values and the variables of interest were crosshead.

RESULTS

There were 1,023 people tested, of which 74% performed risky sexual practices in the last 12 months, both homosexual (50%) and heterosexual (45%), with an age between 18 and 40 years. 18.2% of the users were foreigners and 61.9% had been previously tested. Among the participants in the programme the percentage of reactive tests was 2.1% and the contribution to the diagnosis of new HIV cases in the Region was 4.3%.

CONCLUSIONS

The results of the study show that the community-based programme is an effective tool for the diagnosis of HIV infection in vulnerable groups. In addition, several opportunities for improvement were identified in the process assessment, such as accessibility to the program and the collection of information.

Performance of different serological tests in the diagnosis of natural infection by Leishmania infantum in dogs

Visceral leishmaniasis (VL) is a zoonosis caused by the parasite Leishmania infantum and the dog is its main reservoir in rural and urban areas. The diagnosis of infection is mainly based on the presence of anti-Leishmania IgG antibodies in the serum of infected dogs. In this study, the sensitivity and specificity of qualitative rapid tests (RTs) dual path platform (DPP) Bio-Manguinhos, rapid enzyme-linked immunosorbent assay (ELISA) IDEXX, Kalazar Detect and ALERE, as well as quantitative ELISA Bio-Manguinhos and in-house indirect immunofluorescence assay (IFA) tests were analyzed in sera from infected and uninfected dogs. Serial dilutions of the in-house IFA were compared with RTs and ELISA Bio-Manguinhos. The results showed that none of the tests reached 100% sensitivity and specificity. There was no statistical difference between the analyzed RTs. The most sensitive test was the DPP Bio-Manguinhos (97.9%), while the rapid ELISA IDEXX showed higher specificity (100%). In the treatment setting of infected and/or diseased animals, quantitative tests for monitoring the evolution of antibody titers are required, which indicates the maintenance of in-house IFA in animal handling. Furthermore, we demonstrate that the RTs present higher sensitivity in serum samples with superior antibody titers obtained in the in-house IFA. However, the RTs exhibited false negatives in samples with low titers of antibodies. Among the RTs, only the DPP Bio-Manguinhos presented better performance in this situation. Therefore, the use of RTs for the diagnosis of VL in dogs with low titers of antibodies, such as asymptomatic, should be carefully evaluated.

An inter-laboratory comparison to evaluate the technical performance of rabies diagnosis lateral flow assays

As in previous years, the European Union Reference Laboratory (EURL) for rabies organised in 2018 an Inter-laboratory trial (ILT) on rabies diagnosis. Contrarily to past years, the 2018 ILT did not aim to evaluate the performance of participating laboratories, but the technical performance of new rapid tests. Two lateral Flow Assays (LFA), namely the Anigen® and the CDIA™ Rabies Virus Antigen Rapid Test" (commercialized by Bionote and Creative Diagnostics Cie respectively), were evaluated together with the Fluorescent Antibody Test (FAT). One panel of virus samples (including RABV as well as EBLV1a, EBLV-1b, and EBLV2 strains) was sent to participating laboratories to compare results obtained with these different techniques. The study revealed that the FAT provided a good agreement toward expected results for both negative/positive samples (99.1%). The Anigen® test produced similar results to the FAT, with only one false negative result (0.5%) reported by all participants and a concordance of 100% for all but one sample demonstrating a good inter-laboratory reproducibility of the Anigen® batch. The CDIA™ test produced reproducible results for Rabies Virus (RABV) samples only. However, it hardly detected the Bokeloh Bat Lyssavirus (BBLV) and the European Bat Lyssaviruses types 1b and 2 (EBLV-1b and EBLV-2) in most laboratories resulting in a moderate inter-laboratory concordance (58.4%-82.7%) for these lyssaviruses. The two LFAs provided reliable and reproducible results on all RABV samples (100%) but lead to heterogeneous performances with other lyssaviruses leading to different levels of diagnostic/analytical sensitivity, specificity. The study confirmed that LFAs should be used with caution and that their validation are of upmost importance before any use in laboratories.

Gluten immunogenic peptide excretion detects dietary transgressions in treated celiac disease patients

BACKGROUND

Life-long removal of gluten from the diet is currently the only way to manage celiac disease (CeD). Until now, no objective test has proven useful to objectively detect ingested gluten in clinical practice. Recently, tests that determine consumption of gluten by assessing excretion of gluten immunogenic peptides (GIP) in stool and urine have been developed. Their utility, in comparison with conventional dietary and analytical follow-up strategies, has not been fully established.

AIM

To assess the performance of enzyme-linked immunosorbent assay (ELISA) and point-of-care tests (PoCTs) for GIP excretion in CeD patients on gluten-free diet (GFD).

METHODS

We conducted an observational, prospective, cross-sectional study in patients following a GFD for at least two years. Using the Gastrointestinal Symptom Rating Scale questionnaire, patients were classified at enrollment as asymptomatic or symptomatic. Gluten consumption was assessed twice by 3-d dietary recall and GIP excretion (by ELISA in stool and PoCTs (commercial kits for stool and urine) in two consecutive samples. These samples and dietary reports were obtained 10 day apart one from the other. Patients were encouraged to follow their usual GFD during the study period.

RESULTS

Forty-four patients were enrolled, of which 19 (43.2%) were symptomatic despite being on a GFD. Overall, 83 sets of stool and/or urine samples were collected. Eleven out of 44 patients (25.0%) had at least one positive GIP test. The occurrence of at least one positive test was 32% in asymptomatic patients compared with 15.8% in symptomatic patients. GIP was concordant with dietary reports in 65.9% of cases (Cohen´s kappa: 0.317). PoCT detected dietary indiscretions. Both ELISA and PoCT in stool were concordant (concomitantly positive or negative) in 67 out of 74 (90.5%) samples. Excretion of GIP was detected in 7 (8.4%) stool and/or urine samples from patients considered to be strictly compliant with the GFD by dietary reports.

CONCLUSION

GIP detects dietary transgressions in patients on long-term GFD, irrespective of the presence of symptoms. PoCT for GIP detection constitutes a simple home-based method for self-assessment of dietary indiscretions.

Detection of group a Streptococcus in pharyngitis by two rapid tests: comparison of the BD Veritor™ and the QuikRead go® Strep A

We compared the performance of two rapid antigen tests-QuikRead go® Strep A test (Orion Diagnostica, Espoo, Finland) and BD Veritor™ system (Becton, Dickinson and Company, Sparks, MD) with throat culture. Our aim was to evaluate each assay's performance and agreement compared to throat culture in order to choose one of the assays as a point-of-care test in the emergency room. One hundred throat samples were collected in triplicates from patients with suspected pharyngitis admitted to the emergency room. One throat swab was seeded for a throat culture. The other two throat swabs from each patient were analyzed at the emergency room by the QuikRead go® Strep A test, and by the BD Veritor™ system, according to each manufacturer's instructions. Agreement level between BD Veritor™ test and throat culture was 79%; sensitivity and specificity of this test were 80% and 78.7%, respectively. QuikRead go® Strep A test had an agreement level of 75% with throat culture; sensitivity and specificity of this test were 80% and 73.3%, respectively. Both tests have a good diagnostic performance. Other characteristics such as costs, size of instrument, and ease of implementation should be taken into consideration when choosing a point-of-care test.

Comparisons of New HIV Rapid Test Kit Performance

The development of rapid point-of-care tests for HIV infection has greatly reduced the problem of failure to return for test results. Test manufacturers are now developing test kits that can test for two or even three diseases at the same time, multiple-disease test kits. This study reports on the sensitivity and specificity of HIV tests when included on multi-disease test kits. 1029 participants were recruited from 2011 to 2014. HIV test kit sensitivities ranged from 91.1 to 100%, and the HIV test kit specificities from 99.5 to 100%. The two HIV kits which used oral fluid instead of blood performed well.

Prevalence, clinical features, and diagnosis of Trichomonas vaginalis among female STI clinic attendees in Trinidad

Background

Trichomonas vaginalis (TV) is one of the most common pathogens causing sexually transmitted infections (STIs) in both men and women. Since there are no accurate prevalence data available on TV infection among women for Trinidad and Tobago and in the Caribbean region, there is a great need for research to study the dynamics of the infection and its transmission.

Objectives

To determine the prevalence and diagnose TV infection in women attending the STI clinic and to provide recommendations for control and prevention of trichomoniasis in the community.

Study Design

A cross-sectional study was designed after obtaining the informed consent. Following a routine clinical examination, vaginal swabs were collected - one for wet mount preparation, one for InPouch culture, and other two for OSOM rapid test/and fluorescent antibody testing. Cotton swabs and Dacron swabs were used for testing.

Results

A prevalence of 16% of trichomoniasis out of 422 females was recorded. In all, 65 (65%) were in the age range of 15-29 years and peak of 30% in the age group of 20-24 years. Vaginal discharge was a common complaint (83%); 75.6% had foul odor and only 9.8% had typical fishy odor. The majority of them (87%) had whitish-yellow colored discharge.

Conclusion

Prevalence of trichomoniasis is significant in the female population attending STI clinic. Targeting high-risk age group between 15 and 29 years for control and prevention would be beneficial. Prompt and accurate diagnosis using appropriate laboratory test is recommended.

Performance of rapid tests for carbapenemase detection among Brazilian Enterobacteriaceae isolates

The global emergence of carbapenemases led to the need of developing new methods for their rapid detection. The aim of this study was to evaluate the performance of the rapid tests for carbapenemase-producing and non-producing Enterobacteriaceae. Carbapenem non-susceptible Enterobacteriaceae from a surveillance study submitted to a multiplex real time PCR for carbapenemase detection were included in this study. The isolates were subjected to the rapid phenotypic tests Carba NP, Blue-Carba and Carbapenem Inactivation Method (CIM). A total of 83 carbapenemase-producing (43) and non-producing (40) isolates were included in the study. The sensitivity/specificity were 62.7%/97.5%, 95.3%/100%, and 74.4%/97.5% for Carba NP, Blue-Carba and CIM, respectively. Both Carba NP and Blue-Carba presented their final results after 75 min of incubation; the final results for CIM were obtained only after 8 h. Failure to detect OXA-370 carbapenemase was the main problem for Carba NP and CIM assays. As the Blue-Carba presented the highest sensitivity, it can be considered the best screening test. Conversely, CIM might be the easiest to perform, as it does not require special reagents. The early detection of carbapenemases aids to establish infection control measures and prevent carbapenemases to spread reducing the risk of healthcare associated infections and therapeutic failure.

Evaluation of HIV-1 rapid tests and identification of alternative testing algorithms for use in Uganda

Introduction

The World Health Organization recommends that countries conduct two phase evaluations of HIV rapid tests (RTs) in order to come up with the best algorithms. In this report, we present the first ever such evaluation in Uganda, involving both blood and oral based RTs. The role of weak positive (WP) bands on the accuracy of the individual RT and on the algorithms was also investigated.

Methods

In total 11 blood based and 3 oral transudate kits were evaluated. All together 2746 participants from seven sites, covering the four different regions of Uganda participated. Two enzyme immunoassays (EIAs) run in parallel were used as the gold standard. The performance and cost of the different algorithms was calculated, with a pre-determined price cut-off of either cheaper or within 20% price of the current algorithm of Determine + Statpak + Unigold. In the second phase, the three best algorithms selected in phase I were used at the point of care for purposes of quality control using finger stick whole blood.

Results

We identified three algorithms; Determine + SD Bioline + Statpak; Determine + Statpak + SD Bioline, both with the same sensitivity and specificity of 99.2% and 99.1% respectively and Determine + Statpak + Insti, with sensitivity and specificity of 99.1% and 99% respectively as having performed better and met the cost requirements. There were 15 other algorithms that performed better than the current one but rated more than the 20% price. None of the 3 oral mucosal transudate kits were suitable for inclusion in an algorithm because of their low sensitivities. Band intensity affected the performance of individual RTs but not the final algorithms.

Conclusion

We have come up with three algorithms we recommend for public or Government procurement based on accuracy and cost. In case one algorithm is preferred, we recommend to replace Unigold, the current tie breaker with SD Bioline. We further recommend that all the 18 algorithms that have shown better performance than the current one are made available to the private sector where cost may not be a limiting factor.

Diagnostic yield of real-time polymerase chain reaction in the diagnosis of intrapartum maternal rectovaginal colonization by group B Streptococcus: a systematic review with meta-analysis

Group B Streptococcus is the leading etiologic factor of neonatal sepsis. Intrapartum real-time polymerase chain reaction (RT-PCR) may allow faster and more accurate detection of maternal colonization. The aim of this study was to determine the sensitivity and specificity of RT-PCR when compared to the reference standard culture in selective broth media collected from rectovaginal tract from laboring women. We selected 15 studies that included 6368 women. Papers selection, data extraction, and quality assessment were carried out by two independent researchers. The prevalence of maternal colonization was 23.8% by RT-PCR and 22.1% by culture. The meta-analysis demonstrated an RT-PCR sensitivity of 93.7% (CI 92.1-95.3), and specificity of 97.6% (CI 97.0-98.1). This result is above the cutoff point defined by the Centers for Disease Control and Prevention for clinical usefulness. In conclusion, RT-PCR for GBS screening in labor ward is a promising tool; however, further well-designed studies to justify its use are needed.

Development and evaluation of rapid novel isothermal amplification assays for important veterinary pathogens: Chlamydia psittaci and Chlamydia pecorum

Background

Chlamydia psittaci and Chlamydia pecorum are important veterinary pathogens, with the former also being responsible for zoonoses, and the latter adversely affecting koala populations in Australia and livestock globally. The rapid detection of these organisms is still challenging, particularly at the point-of-care (POC). In the present study, we developed and evaluated rapid, sensitive and robust C. psittaci-specific and C. pecorum-specific Loop Mediated Isothermal Amplification (LAMP) assays for detection of these pathogens.

Methods and Materials

The LAMP assays, performed in a Genie III real-time fluorometer, targeted a 263 bp region of the C. psittaci-specific Cps_0607 gene or a 209 bp region of a C. pecorum-specific conserved gene CpecG_0573, and were evaluated using a range of samples previously screened using species-specific quantitative PCRs (qPCRs). Species-specificity for C. psittaci and C. pecorum LAMP targets was tested against DNA samples from related chlamydial species and a range of other bacteria. In order to evaluate pathogen detection in clinical samples, C. psittaci LAMP was evaluated using a total of 26 DNA extracts from clinical samples from equine and avian hosts, while for C. pecorum LAMP, we tested a total of 63 DNA extracts from clinical samples from koala, sheep and cattle hosts. A subset of 36 C. pecorum samples was also tested in a thermal cycler (instead of a real-time fluorometer) using newly developed LAMP and results were determined as an end point detection. We also evaluated rapid swab processing (without DNA extraction) to assess the robustness of these assays.

Results

Both LAMP assays were demonstrated to species-specific, highly reproducible and to be able to detect as little as 10 genome copy number/reaction, with a mean amplification time of 14 and 24 min for C. psittaci and C. pecorum, respectively. When testing clinical samples, the overall congruence between the newly developed LAMP assays and qPCR was 92.3% for C. psittaci (91.7% sensitivity and 92.9% specificity); and 84.1% for C. pecorum (90.6% sensitivity and 77.4% specificity). For a subset of 36 C. pecorum samples tested in a thermal cycler using newly developed LAMP, we observed 34/36 (94.4%) samples result being congruent between LAMP performed in fluorometer and in thermal cycler. Rapid swab processing method evaluated in this study also allows for chlamydial DNA detection using LAMP.

Discussion

In this study, we describe the development of novel, rapid and robust C. psittaci-specific and C. pecorum-specific LAMP assays that are able to detect these bacteria in clinical samples in either the laboratory or POC settings. With further development and a focus on the preparation of these assays at the POC, it is anticipated that both tests may fill an important niche in the repertoire of ancillary diagnostic tools available to clinicians.

Phenotypical Variability in Bovine Spongiform Encephalopathy: Epidemiology, Pathogenesis, and Diagnosis of Classical and Atypical Forms

After thirty years, bovine spongiform encephalopathy (BSE) still represents the biggest crisis in the field of food safety. Initially detected in the United Kingdom in 1986, BSE spread to many other countries all over the world, involving approximately 200,000 cattle. The origin of BSE is uncertain, but epidemiological studies suggest that the source was cattle feed prepared from prion-infected animal tissues. The implementation of the drastic measures, including the ban of meat and bone meal from livestock feed and the removal of specified risk material from the food chain, has eventually resulted in a significant decline of the epidemic. For many years, it was believed that the disease was caused by transmission of a single prion strain. However, since 2004 two types of BSE, with distinct phenotypical characteristics, have been detected in Italy and France. These atypical types are characterized by distinct Western Blot profiles of abnormal protease-resistant prion protein, named high-type (H-BSE) and low-type (L-BSE). At present, there is no comprehensive information about the origin of the atypical BSEs (sporadic vs. acquired), and data about the pathogenesis of both atypical forms are very limited as compared to the classical type (C-BSE). This chapter will provide a well-organized overview of what is known about classical and atypical BSE. It will review information on the main epidemiological features, pathogenesis, and the criteria for routine diagnosis based on rapid tests, histological, immunohistochemical, and Western blot analysis. Furthermore, a brief overview about the most recently in vitro techniques will be also provided.

Evaluation of rapid tests for diagnosis of acute hepatitis E

BACKGROUND

Hepatitis E virus diagnosis still presents difficulties due to discordant results among diagnostic tests.

OBJECTIVES

The aim of this study was to evaluate the performance of two rapid tests for detection of anti-HEV IgM antibodies.

STUDY DESIGN

The rapid tests were compared with three commercial anti-HEV ELISA assays and one Real-Time PCR assay on 59 sera from patients with acute viral non-AC hepatitis.

RESULTS

The presence of anti-HEV IgM antibodies was evaluated by two rapid tests (Wantai and Assure) on 25 HEV RNA positive samples. Anti-HEV IgM antibodies were detected in 24/25 and 23/25 samples respectively. The sensitivity and specificity of Wantai and Assure Rapid tests were evaluated using the 25 HEV RNA positive samples and 50 HEV RNA negative samples (including sera from acute-phase HAV and HBV infections and blood donors). Overall, the sensitivity of Wantai Rapid and Assure Rapid tests was 96.1% and 92.6% respectively; the specificity of the 2 tests was 100%.

CONCLUSION

Our data suggest the potential use of anti-HEV IgM rapid assays as a first line test in primary health care settings, particularly useful for patients with chronic liver disease or pregnant women who urgently need an antiviral treatment.

Laboratory evaluation of three dual rapid diagnostic tests for HIV and syphilis in China and Nigeria

OBJECTIVE

To determine the laboratory-based performance and operational characteristics of three dual rapid diagnostic tests (RDTs) for testing HIV and syphilis.

METHODS

Three dual RDTs (SD Bioline, Chembio, and MedMira) were evaluated using 1514 serum specimens archived at laboratories or collected from clinics in China and Nigeria to determine sensitivity and specificity, with 95% confidence intervals. Concordance of testing results read by two technicians, stability of testing results read at two time points, and test operation characteristics were also assessed.

RESULTS

All three of the evaluated RDTs gave excellent performance with a combined sensitivity ranging from 99.0%-99.6% for HIV and 98.3%-99.0% for syphilis, and a combined specificity ranging from 97.9%-99.0% for HIV and 97.2%-99.6% for syphilis. Concordance of testing results between two technicians and stability of testing results read within and one hour past the recommended reading period showed excellent agreement, with Kappa greater than or equal to 0.98.

CONCLUSIONS

All the tests were found to be very or fairly easy to use and easy to interpret the results. Further evaluations of these dual RDTs with whole blood in field settings, and more studies on the implication of introduction of these tests in HIV and syphilis control programs are needed.

Accuracy and reproducibility of a rapid chromatographic immunoassay for the diagnosis of canine visceral leishmaniasis in Brazil

BACKGROUND

Visceral leishmaniasis is a major public health concern in Brazil and the domestic dog is the main source of infection. In this study, we aimed to evaluate the accuracy and reliability of a rapid chromatographic immunoassay based on a dual-path platform for the diagnosis of canine visceral leishmaniasis (CVL).

METHODS

Sampling consisted of 428 domestic dogs selected from two neighborhoods in the municipality of Fortaleza, Ceara state, Brazil. The reference standard was composed of three parasitological tests and was applied samples from 333 dogs. The rapid test was used to analyse whole blood and serum samples.

RESULTS

Accuracy of the rapid test in whole blood samples through visual reading (n=305), serum samples through electronic reading (n=333) and serum samples through visual reading (n=333), yielded sensitivities of 87.5% (21/24; 95% CI: 66.5 to 96.7), 88% (22/25; 95% CI: 67.5 to 96.8) and 88% (22/25; 95% CI: 67.5 to 96.8), and specificities of 73.3% (206/281; 95% CI: 67.7 to 78.4), 68.2% (210/308; 95% CI: 62.2 to 74.3) and 69.2% (213/308; 95% CI: 63.7 to 74.3), respectively. Agreement between the visual and electronic readings in 428 serum samples were classified as almost perfect (Kappa Index=0.88; 95% CI: 0.83 to 0.93). The positive predictive value of the test using whole blood samples was 21.9% for the 7.9% prevalence detected by the reference standard in the study sample. A sensitivity analysis of the positive predictive value revealed that it remained below 50% in scenarios with a prevalence of up to 20%.

CONCLUSIONS

The similarity of the accuracy values of the rapid test using whole blood or serum samples, together with its reliable performance in sera through visual and electronic reading, suggests that it may contribute as a screening test for routine use under field-conditions. However, future studies need to improve the accuracy of the test so that it can be successfully implemented in public health programs.

Screening for hepatitis C virus infection in a high prevalence country by an antigen/antibody combination assay versus a rapid test

In low-income-countries, screening for hepatitis C virus (HCV) infection is often based on rapid tests (RT). Their lower sensitivity compared to enzyme immunoassay (EIA) suggests that newer HCV Antigen/Antibody (Ag/Ab) combination assays might have a role in such countries. To test this idea, 1998 blood donors were tested at the University Teaching Hospital blood bank in Yaoundé, Cameroon simultaneously with a RT (HCV rapid test, Human Diagnostics, Berlin, Germany) according to standard practice (S1) and with an Ag/Ab assay (Monolisa HCV Ag/Ab Ultra, Biorad, France) (S2). All discordant, borderline and reactive samples were submitted to confirmatory testing by immunoblot and/or HCV-RNA. Of the 86 (4.3%) samples positive with one or both strategies, 29 were confirmed negative, 37 positive and 20 were false positive or resolved infection. There was a significant difference in test sensitivity (p=0.01) between S1 (70.3%) and S2 (91.9%) but not in test specificity (99.4% and 98.6%, respectively). The benefit of the Ag/Ab assay in the detection of recent HCV seronegative infections could not be evaluated since no Antigen-only donations were identified. However, better Ag/Ab test sensitivity compared to RT supports the implementation of these newer immunoassays for HCV screening in the African blood bank setting.

Access to HIV counseling and testing among people who inject drugs in Central Asia: strategies for improving access and linkages to treatment and care

INTRODUCTION

As a population profoundly affected by the HIV epidemic and in critical need of linkages to HIV treatment and care, PWID in Central Asia remain largely underserved. This paper provides an overview of the current state of HIV testing and counseling in Central Asia for PWID, identifies main barriers leading to gaps in service delivery, and discusses implications for improving strategies that promote HIV testing for PWID.

METHODS

We reviewed a number of sources for this paper including unpublished government reports, published papers, and Ministries of Health of Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan country progress reports to the UN General Assembly Special Session on HIV/AIDS (UNGASS) for 2012.

RESULTS

Between 29 and 65% of PLWH in some Central Asian countries have been tested for HIV in the last 12 months. The rates have been increasing in the recent years but still are relatively low. Stigma, discrimination, human rights violations, and repressive legislation are barriers to HTC for people who inject drugs (PWID).

CONCLUSION

The use of innovative evidence-based HTC models, such as community mobile-vans, self-testing at home, and rapid HIV testing among PWID in Central Asia are discussed and recommendations given regarding amendments in legislation and scaling up of existing community-based pilot projects to support HIV testing among PWID in CA.