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Background: Quantitative Cytomegalovirus (CMV) polymerase chain reactions are increasingly being used for monitoring CMV DNAemia in haematopoietic stem cell transplants and solid organ transplants. Objective: In this study, a commercial CMV viral load assay was compared with an in-house viral load assay. Materials and Methods: A total of 176 whole-blood samples were tested for CMV DNAemia using both assays. Results: Our evaluation showed a difference of 1 log10copies/ml between the two assay systems in determining CMV viral loads in the clinical samples. Conclusion: The in-house viral load assay had a better correlation with clinical findings compared to the commercial assay. Quality assessment of these assays was done by the United Kingdom National External Quality Assessment Scheme (UKNEQAS), an external proficiency testing programme, and by the National Institute for Biological Standard and Control (NIBSC) standard. For UKNEQAS and NIBSC standards, the bias between the assays was 0.73 log10and 0.85 log10, respectively. This difference is well within the acceptable range already reported in the literature.
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This study has evaluated the performance of a rapid immunochromatographic test (ICT) device in detecting antibodies to Dengue virus (DENV) in a tertiary hospital in South India. Sera from hospital attendees, with requests for DENV antibody testing, were tested with the Panbio Dengue Duo Cassette and a reference antibody capture assay for the detection of IgM (Dengue IgM capture ELISA-National Institute of Virology, India) and IgG (Dengue IgG capture ELISA-Panbio Diagnostics Inc., Australia) antibodies. The ICT results were compared with results of antibody capture tests for the detection of the IgM and IgG antibodies, respectively. Accuracy indices for IgM and IgG detection, respectively were - sensitivity 81.8% and 87.5%, specificity 75.0%, and 66.6%, positive predictive value (PPV) 61.0% and 72.9% and negative predictive value (NPV) 89.6% and 83.9%. The device performs poorly in detection of IgM and IgG antibodies to DENVs and is not recommended for use as a stand-alone diagnostic test.
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PURPOSE: Seroepidemiological studies on the prevalence of Hepatitis C virus (HCV) in India have been hampered by reluctance of subjects to provide blood samples for testing. We evaluated the use of saliva as an alternate specimen to blood for the detection of antibodies to HCV. METHODS: Chronic liver disease (CLD) patients attending the liver clinic were recruited for this study. A saliva and plasma sample (sample pair) was collected from each patient included in the study. Saliva samples were collected using a commercially available collection device--OmniSal. Sample pairs were tested with an in-use ELISA for the detection of antibodies to HCV (HCV-Ab), with a minor modification in the manufacturer's protocol while testing saliva. The cut-off absorbance value for declaring a sample as positive was determined by receiver operating curve (ROC) analysis. HCV-Ab positivity in saliva was compared with that in plasma as well as with viral load in plasma and infecting genotype of the virus. Sensitivity, specificity, positive and negative predictive values, and correlation coefficients were calculated using Medcalc statistical software. RESULTS: The optimal accuracy indices were: sensitivity-81.6%; specificity-92.5%; PPV-85.1% and NPV-90.5%. No correlation was found between salivary positivity and HCV viral load in plasma or infecting genotype. CONCLUSIONS: The accuracy indices indicate that the assay must be optimized further before it can be recommended for routine use in epidemiological surveys for HCV-Ab.