Comparative Evaluation of Commercial Test Kits Cleared for Use in Modified Two-Tiered Testing Algorithms for Serodiagnosis of Lyme Disease.

BACKGROUND: Modified 2-tiered testing (MTTT) for Lyme disease utilizes automatable, high throughput immunoassays (AHTIs) in both tiers without involving western immunoblots, offering performance and practical advantages over standard 2-tiered testing (STTT; first-tier AHTI followed by immunoglobulin M (IgM) and immunoglobulin G (IgG) western immunoblots). For MTTT, Centers for Disease Control and Prevention recommends using AHTI test kits that have been cleared by Food and Drug Administration (FDA) specifically for this intended use. We evaluated performance of FDA-cleared MTTT commercial test kits from 3 manufacturers by comparing with STTT results. METHODS: We performed MTTT (total antibody AHTI with reflex to separate IgM and IgG AHTIs) using test kits from Diasorin, Gold Standard Diagnostics (GSD), and Zeus Scientific on 382 excess serum samples submitted to the clinical laboratory for routine Lyme disease serologic testing in July 2018, measuring agreement between MTTT and STTT using the κ statistic. RESULTS: Overall agreement with STTT was 0.87 (95% confidence interval [CI], .77-.97) using Diasorin assays (almost perfect agreement), 0.80 (95% CI, .68-.93) using GSD assays (substantial agreement) and 0.79 (95% CI, .68-.90) using Zeus assays (substantial agreement). For detection of IgM reactivity, agreement between MTTT and STTT was 0.70 (.51-.90; substantial), 0.63 (95% CI, .44-.82; substantial) and 0.56 (95% CI, .38-.73; moderate), respectively. For detection of IgG reactivity, MTTT/STTT agreement was 0.73 (95% CI,.58-.88), 0.78 (95% CI, .62-.94), and 0.75 (95% CI, .60-.90), respectively (substantial agreement in all cases). CONCLUSIONS: MTTT results obtained using commercial test kits from 3 different manufacturers had substantial to almost perfect agreement with STTT results overall and moderate to substantial agreement for IgM and IgG detection independently. Commercial MTTT tests can be used broadly for the diagnosis of Lyme disease.

Diagnostic accuracy of commercially available serological tests for the detection of measles and rubella viruses: a systematic review and meta-analysis.

Measles and rubella serological diagnoses are done by IgM detection. The World Health Organization Global Measles and Rubella Laboratory Network previously endorsed Siemens Enzygnost enzyme-linked immunosorbant assay kits, which have been discontinued. A recommended replacement has not been determined. We aimed to search for suitable replacements by conducting a systematic review and meta-analysis of IgM detection methods that are currently available for measles and rubella. A systematic literature search was performed in Medline, Embase, Global Health, Cochrane Central, and Scopus on March 22 and on 27 September 2023. Studies reporting measles and/or rubella IgM detection with terms around diagnostic accuracy were included. Risk of bias was assessed using QUADAS tools. Meta-DiSc and R were used for statistical analysis. Clinical samples totalling 5,579 from 28 index tests were included in the measles meta-analysis. Sensitivity and specificity of the individual measles studies ranged from 0.50 to 1.00 and 0.53 to 1.00, respectively. Pooled sensitivity and specificity of all measles IgM detection methods were 0.94 (CI: 0.90-0.97) and 0.94 (CI: 0.91-0.97), respectively. Clinical samples totalling 4,983 from 15 index tests were included in the rubella meta-analysis. Sensitivity and specificity of the individual rubella studies ranged from 0.78 to 1.00 and 0.52 to 1.00, respectively. Pooled sensitivity and specificity of all rubella IgM detection methods were 0.97 (CI: 0.93-0.98) and 0.96 (CI: 0.93-0.98), respectively. Although more studies would be ideal, our results may provide valuable information when selecting IgM detection methods for measles and/or rubella.

Performance of the Applied Biosystems HIV-1 Genotyping Kit with Integrase.

HIV genotyping is used to assess HIV susceptibility to antiretroviral drugs. The Applied Biosystems HIV-1 Genotyping Kit with Integrase (AB kit, Thermo Fisher Scientific) detects resistance-associated mutations (RAMs) in HIV protease (PR), reverse transcriptase (RT), and integrase (IN). We compared results from the AB kit with results obtained previously with the ViroSeq HIV-1 Genotyping System. DNA amplicons from the AB kit were also analyzed using next-generation sequencing (NGS). HIV RNA was extracted using the MagNA Pure 24 instrument (Roche Diagnostics; 96 plasma samples, HIV subtype B, viral load range: 530-737,741 copies/mL). FASTA files were generated from AB kit data using Exatype (Hyrax Biosciences). DNA amplicons from the AB kit were also analyzed by NGS using the Nextera XT kit (Illumina). Drug resistance was predicted using the Stanford HIV Drug Resistance Database. The mean genetic distance for sequences from ViroSeq and the AB kit was 0.02% for PR/RT and 0.04% for IN; 103 major RAMs were detected by both methods. Four additional major RAMs were detected by the AB kit only. These four major RAMs were also detected by NGS (detected in 18.1%-38.2% of NGS reads). NGS detected 27 major RAMs that were not detected with either of the Sanger sequencing-based kits. All major RAMs detected with ViroSeq were detected with the AB kit; additional RAMs were detected with the AB kit only. DNA amplicons from the AB kit can be used for NGS for more sensitive detection of RAMs.

Comparison of diagnostic performance among Abbott RealTime HCV Genotyping II, Abbott HCV Genotype plus RUO, and Roche Cobas HCV Genotyping assays for hepatitis C virus genotyping.

Comparison of diagnostic accuracy for commercial hepatitis C virus (HCV) genotyping (Abbott RealTime HCV Genotyping II, Roche Cobas Genotyping) and investigational Abbott HCV Genotype plus RUO assays designed to discriminate genotype (GT)-1a, 1b or 6 in cases of ambiguous GT from the Abbott commercial assay remains limited. 743 HCV-viremic samples were subjected to analysis using Abbott and Roche commercial as well as Abbott HCV Genotype plus RUO assays. Next-generation sequencing (NGS) targeting core region was employed as the reference standard. Diagnostic accuracy was reported as the number of participants (percentages) along with 95% confidence intervals (CIs). Using NGS, 741 samples (99.7%) yielded valid genotyping results. The diagnostic accuracies were 97.6% (95% CI: 96.1%-98.5%) and 95.3% (95% CI: 93.4%-96.6%) using Abbott and Roche commercial assays (p = 0.0174). Abbott commercial assay accurately diagnosed HCV GT-6a and 6w, whereas Roche commercial assay accurately diagnosed HCV GT-6a. Both assays demonstrated low accuracies for HCV GT-6b, 6e, 6g, and 6n. Abbott HCV Genotype plus RUO assay discriminated 13 of the 14 samples (92.9%; 95% CI: 64.2%-99.6%) that yielded ambiguous GT. Both assays were capable of diagnosing mixed HCV infections when the minor genotype comprised >8.4% of the viral load. The diagnostic performance of commercial HCV genotyping assays is commendable. Abbott assay demonstrated superior performance compared to Roche assay in diagnosing HCV GT-6. Abbott HCV Genotype plus RUO assay aids in discriminating ambiguous GT. Both commercial assays are proficient in diagnosing mixed HCV infections at a cut-off viral load of 8.4% in minor genotype.

Comparative analysis of commercially available kits for optimal DNA extraction from bovine fecal samples.

In the field of metagenomic research, the choice of DNA extraction methods plays a pivotal yet often underestimated role in shaping the reliability and interpretability of microbial community data. This study delves into the impact of five commercially available DNA extraction kits on the analysis of bovine fecal microbiota. Recognizing the importance of accurate DNA extraction in elucidating microbial community dynamics, we systematically assessed DNA yield, quality, and microbial composition across these kits using 16S rRNA gene sequencing. Notably, the FastDNA spin soil kit yielded the highest DNA concentration, while significant variations in quality were observed across kits. Furthermore, differential abundance analysis revealed kit-specific biases that impacted taxa representation. Microbial richness and diversity were significantly influenced by the choice of extraction kit, with QIAamp DNA stool minikit, QIAamp Power Pro, and DNeasy PowerSoil outperforming the Stool DNA Kit. Principal-coordinate analysis revealed distinct clustering based on DNA isolation procedures, particularly highlighting the unique microbial community composition derived from the Stool DNA Kit. This study also addressed practical implications, demonstrating how kit selection influences the concentration of Gram-positive and Gram-negative bacterial taxa in samples. This research highlights the need for consideration of DNA extraction kits in metagenomic studies, offering valuable insights for researchers striving to advance the precision and depth of microbiota analyses in ruminants.

Concordance between an FDA-approved companion diagnostic and an alternative assay kit for assessing homologous recombination deficiency in ovarian cancer.

OBJECTIVE: Authors evaluated the performance of a commercially available next-generation sequencing assay kit; this was based on genomic content from Illumina's TruSight™ Oncology 500 research assay that identifies BRCA variants and proprietary algorithms licensed from Myriad and, with additional genomic content, measures the homologous recombination deficiency (HRD) genomic instability score (GIS) in tumor tissue (TSO 500 HRD assay). METHODS: Data from the TSO 500 HRD assay were compared with data from the Myriad MyChoice®CDx PLUS assay (Myriad assay). Prevalence rates for overall HRD status and BRCA mutations (a deleterious or suspected deleterious BRCA1 or BRCA2 mutation or both) and assay agreement rates for HRD GIS and BRCA analysis were assessed in ovarian tumor samples. Pearson correlations of the continuous HRD GIS and analytic sensitivity and specificity were evaluated. RESULTS: The prevalence of overall HRD positivity was 51.2% (TSO 500 HRD assay) versus 49.2% (Myriad assay) and the prevalence of BRCA mutations was 27.6% (TSO 500 HRD assay) versus 25.5% (Myriad assay). After post-processing optimization, concordance of the HRD GIS was 0.980 in all samples and 0.976 in the non-BRCA mutation cohort; the area under the receiver operating characteristic curve was 0.995 and 0.992, respectively. CONCLUSIONS: Comparison between the Illumina and Myriad assays showed that overall HRD status, the individual components of BRCA analysis, and HRD GIS detection results were highly concordant (>93%), suggesting the TSO 500 HRD assay will approach the analytical accuracy of the FDA-approved Myriad assay.

Detection of intrathecal IgG antibody for varicella and measles diagnosis by evaluation and comparison of a commercial IgG chemiluminescent immunoassay with two ELISAs.

OBJECTIVES: Analyse alternative methods of intrathecal antibody detection by comparing chemiluminescent immunoassay (CLIA) and enzyme-linked immunosorbent assay (ELISA) techniques to determine if CLIA can replace ELISA in the diagnosis of CNS infections. METHODS: A panel of 280 paired samples-cerebrospinal fluid (CSF) and serum-with known antibody reactivities (Varicella, n = 60; Measles, n = 120) and negative samples (n = 100) were used to evaluate the performance of six serological test kits (Enzygnost, VirClia®, and Serion ELISA (Measles and Variella). RESULTS: For Measles virus IgG, the VirClia® IgG monotest revealed 97% and 94% positive and negative agreement to the Enzygnost as reference test, respectively. In contrast, Serion ELISA kits yielded values of 18% and 90%. For the Varicella Zoster virus (VZV) IgG, the VirClia® IgG monotest showed 97% and 90% positive and negative agreement compared to Enzygnost. The Serion ELISA kits showed values of 55% and 86%, respectively. ROC analysis revealed that the areas under the curve for Measles and VZV IgGs were 0.7 and 0.852, respectively, using the Serion kit, and 0.963 and 0.955, for Vircell S.L CLIA technique. VirClia® monotest values were calculated using an antibody index cut-off of 1.3. CONCLUSION: The findings indicate that CLIA testing can improve antibody detection in CSF samples, aiding the diagnosis of infectious neurological impairments.

[Comparison of Cytomegalovirus Polymerase Chain Reaction Test Results Obtained with Fully Automated Systems: Roche Cobas 6800 and Qiagen NeuMoDx Experience]. / Tam Otomatize Sistemlerde Çalisilan Sitomegalovirüs Polimeraz Zincir Reaksiyonu Test Sonuçlarinin Karsilastirilmasi: Roche Cobas 6800 ile Qiagen NeuMoDx Deneyimi.

Viral load monitoring is important in identifying patients at risk of developing cytomegalovirus (CMV) related complications after transplantation and for this purpose, quantitative real-time polymerase chain reaction (Rt-qPCR) tests are most commonly used. The main problem in CMV DNA Rt-qPCR tests that make quantitative measurements is that there are significant differences in measurements performed with different kits in different laboratories. Comparability of viral load measurements between laboratories has increased with the introduction of quantitative PCR tests calibrated with the CMV International Quantitation Standard (IQS) developed by the World Health Organization (WHO). However, quantitative agreement between measurements made with different kits has still not been fully achieved. In this study, it was aimed to investigate the quantitative compatibility between measurements made with Cobas 6800 (Roche Diagnostics, Mannheim, Germany) and NeuMoDx (Qiagen, Ann Arbor, USA) CMV DNA Rt-qPCR tests, which are fully automated new generation systems calibrated with the WHO CMV IQS. The results of 214 plasma samples, which were studied simultaneously with Cobas 6800 CMV Rt-qPCR and NeuMoDx CMV Rt-qPCR tests were analyzed. In the tests, the extraction, amplification and detection stages were carried out fully automatically. CMV DNA was detected in 144 (67.28%) samples in both tests and was not detected in 53 (24.76%) samples. Incompatible results were obtained in a total of 17 (7.94%) samples. Good agreement was found between the qualitative results of both tests (kappa= 0.80, p< 0.001). When the quantitative results (n= 129) obtained in the dynamic measurement range of both tests were examined, the median viral load values measured by Cobas 6800 CMV Rt-qPCR and NeuMoDx CMV Rt-qPCR tests were 513 IU/mL (range= 35-37000) and 741 IU/mL (range= 68-48978), respectively. According to the correlation analysis, a very strong correlation was found between the results of both tests (r= 0.94, p< 0.001). According to Bland-Altman analysis; the average difference between the results of the NeuMoDx CMV Rt-qPCR test and the Cobas 6800 CMV Rt-qPCR test was found to be -0.14 log10 [standard deviation (SD)= 0.23] IU/mL and it was determined that the Cobas 6800 CMV Rt-qPCR test had lower measurements than the NeuMoDx CMV Rt-qPCR test. In 120 of 129 samples (93%) whose results were within the dynamic measurement range of both tests, the measurement difference was within ± 0.5 log10 IU/mL and in 9 (7%), it was detected as more than ± 0.5 log10 (median 0.54 log10 IU/ml; range= 0.51-0.81). No measurement difference of more than ± 1.0 log10 was detected in any sample. In this study, quantitative agreement was found in the measurements made in plasma samples with the fully automated Cobas 6800 CMV Rt-qPCR and NeuMoDx CMV Rt-qPCR tests calibrated with the CMV IQS. To the best of our knowledge, a study comparing viral load measurements made with Cobas 6800 and NeuMoDx fully automated systems in the detection of CMV DNA has not yet been conducted, and this is the first study on this subject.

[Analysis of problems and management of in vitro diagnostic reagent clinical trials in medical laboratory].

Clinical trials are an important method for evaluating the safety and efficacy of in vitro diagnostic reagents, and are a key basis for product registration review and approval. In order to strengthen the management of clinical trials of in vitro diagnostic reagents, the National Medical Products Administration and relevant departments have formulated a series of regulations at the regulatory level, and require applicants and clinical trial institutions to establish a quality management system for clinical trials of in vitro diagnostic reagents. Medical laboratory is the main department and implementer of in vitro diagnostic reagent clinical trials in medical institutions. In recent years, with the rapid development of the in vitro diagnostic industry, the clinical trial projects of in vitro diagnostic reagents conducted by medical laboratory have been increasing day by day. However, there are currently few discussions on the clinical trial of in vitro diagnostic reagents from the perspective of researchers. Therefore, this article summarizes the characteristics of clinical trials of in vitro diagnostic reagents, analyzes the problems and difficulties in conducting clinical trials of in vitro diagnostic reagents in current medical laboratories, and introduces the laboratory's experience in management; to provide reference for medical testing laboratories that have not yet conducted or have already conducted clinical trials of in vitro diagnostic reagents, in order to improve the quality and efficiency of clinical trials.

Direct RT-qPCR detection of SARS-CoV-2 RNA from patient nasopharyngeal swabs without an RNA extraction step.

The ongoing COVID-19 pandemic has created an unprecedented need for rapid diagnostic testing. The World Health Organization (WHO) recommends a standard assay that includes an RNA extraction step from a nasopharyngeal (NP) swab followed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to detect the purified SARS-CoV-2 RNA. The current global shortage of RNA extraction kits has caused a severe bottleneck to COVID-19 testing. The goal of this study was to determine whether SARS-CoV-2 RNA could be detected from NP samples via a direct RT-qPCR assay that omits the RNA extraction step altogether. The direct RT-qPCR approach correctly identified 92% of a reference set of blinded NP samples (n = 155) demonstrated to be positive for SARS-CoV-2 RNA by traditional clinical diagnostic RT-qPCR that included an RNA extraction. Importantly, the direct method had sufficient sensitivity to reliably detect those patients with viral loads that correlate with the presence of infectious virus. Thus, this strategy has the potential to ease supply choke points to substantially expand COVID-19 testing and screening capacity and should be applicable throughout the world.

Detection of SARS-CoV-2 RNA by multiplex RT-qPCR.

The current quantitative reverse transcription PCR (RT-qPCR) assay recommended for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing in the United States requires analysis of 3 genomic targets per sample: 2 viral and 1 host. To simplify testing and reduce the volume of required reagents, we devised a multiplex RT-qPCR assay to detect SARS-CoV-2 in a single reaction. We used existing N1, N2, and RP primer and probe sets by the Centers for Disease Control and Prevention, but substituted fluorophores to allow multiplexing of the assay. The cycle threshold (Ct) values of our multiplex RT-qPCR were comparable to those obtained by the single assay adapted for research purposes. Low copy numbers (≥500 copies/reaction) of SARS-CoV-2 RNA were consistently detected by the multiplex RT-qPCR. Our novel multiplex RT-qPCR improves upon current single diagnostics by saving reagents, costs, time, and labor.

ISO 15189 is a sufficient instrument to guarantee high-quality manufacture of laboratory developed tests for in-house-use conform requirements of the European In-Vitro-Diagnostics Regulation.

The EU In-Vitro Diagnostic Device Regulation (IVDR) aims for transparent risk-and purpose-based validation of diagnostic devices, traceability of results to uniquely identified devices, and post-market surveillance. The IVDR regulates design, manufacture and putting into use of devices, but not medical services using these devices. In the absence of suitable commercial devices, the laboratory can resort to laboratory-developed tests (LDT) for in-house use. Documentary obligations (IVDR Art 5.5), the performance and safety specifications of ANNEX I, and development and manufacture under an ISO 15189-equivalent quality system apply. LDTs serve specific clinical needs, often for low volume niche applications, or correspond to the translational phase of new tests and treatments, often extremely relevant for patient care. As some commercial tests may disappear with the IVDR roll-out, many will require urgent LDT replacement. The workload will also depend on which modifications to commercial tests turns them into an LDT, and on how national legislators and competent authorities (CA) will handle new competences and responsibilities. We discuss appropriate interpretation of ISO 15189 to cover IVDR requirements. Selected cases illustrate LDT implementation covering medical needs with commensurate management of risk emanating from intended use and/or design of devices. Unintended collateral damage of the IVDR comprises loss of non-profitable niche applications, increases of costs and wasted resources, and migration of innovative research to more cost-efficient environments. Taking into account local specifics, the legislative framework should reduce the burden on and associated opportunity costs for the health care system, by making diligent use of existing frameworks.

[A Brief Discussion on the in Vitro Diagnostic Reagent Inspection Practice of Self-examination Management Regulations for Medical Device Registration].

On October 21, 2021, the National Medical Products Administration issued and implemented the Self-examination Management Regulations for Medical Device Registration. The regulations clarify the specific requirements of the registration applicants in the process of self-examination, and put forward detailed requirements from the aspects of self-examination ability, self-examination report, declaration materials and responsibility requirements, so as to ensure the orderly development of the self-examination of medical device registration. Based on the actual verification work of in vitro diagnostic reagent, this study briefly discussed the understanding of the relevant contents of the regulations, aiming to provide some reference for enterprises and related supervision departments that have the requirement of registered self-examination.

Useful manifestations to detect adenovirus in children with upper respiratory infections: A retrospective study.

OBJECTIVE: Approximately 1 million adenovirus immunochromatography (IC) kits are annually used in Japan. However, no practical strategies have been developed regarding their use for detecting adenovirus. The present study aims to verify the usefulness of clinical manifestations in making decisions regarding the use of adenovirus IC kits for children with upper respiratory infections (URI). METHODS: The medical records of 825 pediatric cases tested by IC kits for adenovirus were extracted from clinical laboratory department database over a 3-year period at our hospital. Among them, 585 patients were suspected adenovirus URI, and their clinical manifestations were reviewed. After data cleaning, 10 types of clinical manifestations were statistically analyzed between adenovirus IC kit-positive and -negative groups. Multivariate analysis was performed to select significant clinical manifestations using adenovirus IC kit positivity as the objective variable. RESULTS: Among 585 pediatric patients, the cases of 420 patients, with suitable data for whom no other pathogen was detected, were reviewed. Adenovirus was detected in 86 cases. Multivariate analysis identified a significant difference for three clinical manifestations: (1) fever ≥ 39.0°C, (2) rhinorrhea, and (3) tonsillar exudate. The negativity rate for the IC kit was 90% when none of the three manifestations was observed. CONCLUSIONS: The results suggested that IC kits for adenovirus tend to give negative results in cases that lack all the three above mentioned clinical manifestations.

Development of SARS-CoV-2 packaged RNA reference material for nucleic acid testing.

Nucleic acid tests to detect the SARS-CoV-2 virus have been performed worldwide since the beginning of the COVID-19 pandemic. For the quality assessment of testing laboratories and the performance evaluation of molecular diagnosis products, reference materials (RMs) are required. In this work, we report the production of a lentiviral SARS-CoV-2 RM containing approximately 12 kilobases of its genome including common diagnostics targets such as RdRp, N, E, and S genes. The RM was measured with multiple assays using two different digital PCR platforms. To measure the homogeneity and stability of the lentiviral SARS-CoV-2 RM, reverse transcription droplet digital PCR (RT-ddPCR) was used with in-house duplex assays. The copy number concentration of each target gene in the extracted RNA solution was then converted to that of the RM solution. Their copy number values are measured to be from 1.5 × 105 to 2.0 × 105 copies/mL. The RM has a between-bottle homogeneity of 4.80-8.23% and is stable at 4 °C for 1 week and at -70 °C for 6 months. The lentiviral SARS-CoV-2 RM closely mimics real samples that undergo identical pre-analytical processes for SARS-CoV-2 molecular testing. By offering accurate reference values for the absolute copy number of viral target genes, the developed RM can be used to improve the reliability of SARS-CoV-2 molecular testing.

Evaluation of the Genmark ePlex® and QIAstat-Dx® respiratory pathogen panels in detecting bacterial targets in lower respiratory tract specimens.

BACKGROUND: The ePlex® and QIAstat-Dx® respiratory pathogen panels detect multiple respiratory pathogens, mainly viruses but also Legionella pneumophila, Mycoplasma pneumoniae and Bordetella pertussis. The assays have been marketed for use in nasopharyngeal swab specimens. For diagnosing bacterial pneumonia, lower respiratory tract (LRT) specimens are indicated. Aim of this study was to evaluate the performance of these syndromic panels for these three bacterial targets in samples from the LRT. Fifty-six specimens were collected from our repositories, five negative samples and fifty-one samples which had been previously tested positive with the routine diagnostic real-time PCR assays for Legionella spp. (N = 20), Bordetella spp. (N = 16) or M. pneumoniae (N = 15). RESULTS: The QIAstat-Dx Respiratory Panel V2 (RP) assay detected all of the L. pneumophila and B. pertussis positive samples but only 11/15 (73.3 %) of the M. pneumoniae targets. The ePlex Respiratory Pathogen Panel (RPP) assay detected 10/14 (71.4 %) of the L. pneumophila targets, 8/12 (66.7 %) of the B. pertussis positive samples and 13/15 (86.7 %) of the M. pneumoniae targets. CONCLUSIONS: No false-positive results were reported for all three bacterial pathogens by both assays. The clinical performance of both assays depended highly on the bacterial load in the sample and the type of specimen under investigation.

Real-world application of the Xpert® HBV viral load assay on serum and dried blood spots.

As we strive towards the WHO goal of elimination of viral hepatitis as a public health threat by 2030, implementation of reliable, accurate diagnostic assays is crucial to identify those at risk of disease progression and those at risk of transmission. Ironically those at greatest risk of chronic hepatitis B are often in resource-poor regions with limited access to testing, collection, storage, and/or transportation of peripheral blood. The Xpert® HBV Viral Load assay provides an easy to use, convenient means of measuring load on GeneXpert platforms. In this study, the Xpert assay is evaluated against four commercially available high-throughput assays for Hepatitis B virus (HBV) loads. In addition application of dried blood spots (DBS) for estimation of viral load is assessed on real-world samples collected from a remote Pacific Island, Kiribati. A total of 107 serum/plasma samples were tested in the Xpert HBV load assay and compared with the Abbott m2000, Alinity m, and Roche Cobas CAP/CTM and 6800. Fifty-three DBS were tested in the Xpert assay and compared with matching serum samples. Overall 82% serum/plasma samples demonstrated good correlation between the Xpert and Roche and Abbott assays, to within 0.5 log10 IU/ml. The greatest discrepancies were seen at the limits of quantification of all assays. About 85.4% DBS gave estimable viral loads to within 1 log10 IU/ml of the serum load. The Xpert HBV viral load assay is recommended for all settings but particularly useful for resource-poor settings. Utility of DBS with the Xpert assay provides a simple means for testing in remote settings.

Detection and confirmation of dengue pre- and postintroduction of dengue NS1-antigen test at the University Malaya Medical Centre: An observational study.

Early diagnosis of dengue is important to ensure proper management of patients and effective implementation of control measures. The present study was undertaken to determine the outcome of the implementation of dengue NS1-antigen (Ag) rapid diagnostic test (RDT) in the confirmation of dengue at the first patient hospital visit at the University Malaya Medical Centre. A total of 1036 and 1097 sera from the year 2008 and 2015 were used, representing samples from before and after dengue NS1-Ag RDT was implemented as routine diagnostic at the hospital. Results showed that similar dengue confirmation percentage (56%) was made in 2008 and 2015, regardless of the main laboratory diagnostic method used. Confirmation of dengue, however, increased to 68% and 73% when dengue NS1-Ag test or dengue immunoglobulin M-capture enzyme-linked immunosorbent assay was used as the second test for the 2008 and 2015 samples, respectively. Detection of dengue virus (DENV) using multiplex reverse transcription-polymerase chain reaction (RT-PCR) showed that DENV-1 was the highest in circulation in 2008 and that both DENV-1 and DENV-2 were dominant in 2015. In summary, the present study demonstrated that the introduction and use of the dengue NS1-Ag RDT did not change or compromise confirmation of dengue, highlighting the advantage of using the method. With the reducing cost of molecular detection tools, DENV detection using RT-PCR remains a viable option for further confirmation of dengue in hospital settings.

Evaluation of Abbott Architect, Siemens Immulite, bioMerieux Vidas, and Euroimmune assays for determination of Epstein-Barr virus serological diagnosis.

Serological tests detecting antibodies for Epstein-Barr virus (EBV) antigens are frequently used to define infection status. Several new automated assays are available for this purpose. We compared the performance of Architect, Immulite, Vidas, and Euroimmune immunofluorescence assays (IFA)/enzyme-linked immunosorbent assays (ELISA) for the detection of EBV viral capsid antigen (VCA) immunoglobulin M (IgM), VCA IgG, Epstein-Barr nuclear antigen (EBNA)-1 IgG. The routine diagnosis of EBV in our laboratory is done by anti-EBV VCA IgM IFT, anti-EBV VCA IgG IFT, and anti-EBNA-1 IgG ELISA (Euroimmune) Kits. Samples were tested with EBV Kits of Architect, Immulite, and Vidas for anti-VCA IgM, anti-VCA IgG, and anti-EBNA-1 IgG. The agreement between assays was calculated for each marker individually and for the determination of the EBV infection profile, based on the combination of three markers. BIOCHIP Sequence EBV (Avidity test) and/or EUROLINE EBV Profile 2 (IgG/IgM) were used as confirmatory assays to resolve discrepancies. The best concordance for VCA IgM detection was between Immulite and Vidas; for VCA IgG and EBNA-1 IgG were between Architect and Vidas. The sensitivities and specificities for VCA IgM were 97% and 88% for IFA, 100% and 94% for Architect, 100% and 99% for Vidas, and 100% and 100% for Immulite, respectively. The most problematic marker was EBNA-1 IgG with a 68.1% specificity by Immulite. Vidas panel had a perfect performance (100%) for determining all EBV profiles. Overall, evaluated assays had comparable performance. There were more discordant VCA IgG and EBNA-1 IgG results than VCA IgM results. The agreement between Architect and Vidas was better than other assays.

Comparison of seven heterophile antibody assays for laboratory diagnosis of infectious mononucleosis in pediatric patients.

Heterophile antibody assays have been used to aid the diagnosis of infectious mononucleosis caused by the Epstein-Barr virus. Seven commercially available assays currently widely utilized in clinical laboratories were compared in this study. Variable performance characteristics and assay times are observed, and these pieces of data may assist clinical laboratories in assay selection and result interpretation.