Evaluation of the NucliSens EasyQ v2.0 Assay in Comparison with the Roche Amplicor v1.5 and the Roche CAP/CTM HIV-1 Test v2.0 in Quantification of C-Clade HIV-1 in Plasma

Human immunodeficiency virus type 1 (HIV-1) genetic diversity poses a challenge to reliable viral load monitoring. Discrepancies between different testing platforms have been observed, especially for non-clade-B virus. Therefore we compare, in antiretroviral therapy (ART)-naïve South African subjects predominantly infected with HIV-1 clade-C, three commercially available assays: the COBAS AmpliPrep/COBAS TaqMan HIV-1 Test version 2.0 by Roche (CAP/CTM v2.0), the BioMérieux NucliSens Version 2.0 Easy Q/Easy Mag (NucliSens v2.0) and the Roche COBAS Amplicor HIV-1 Monitor Test Version 1.5 (Amplicor v1.5). Strong linear correlation was observed and Bland-Altman analyses showed overall good agreement between the assays with mean viral load differences of 0.078 log cp/ml (NucliSens v2.0 – Amplicor v1.5), 0.260 log cp/ml (CAP/CTM v2.0 – Amplicor v1.5) and 0.164 log cp/ml (CAP/CTM v2.0 – NucliSens v2.0), indicating lower mean viral load results for the Amplicor v1.5 and higher mean readings for the CAP/CTM v2.0. Consistent with observations following previous comparisons of CAP/CTM v2.0 versus Amplicor v1.5, the CAP/CTM v2.0 assay detected low-level viremia (median 65 cp/ml) in more than one-third of those in whom viremia had been undetectable (<20 cp/ml) in assays using the NucliSens platform. These levels of viremia are of uncertain clinical significance but may be of importance in early detection of ART resistance in those on treatment. Overall the three assays showed good comparability of results but with consistent, albeit relatively small, discrepancies for HIV-1 clade-C samples, especially in the low-viremic range that should be taken into account when interpreting viral load data

Quality of home-based rapid HIV testing by community lay counsellors in a rural district of South Africa

INTRODUCTION: Lack of universal, annual testing for human immunodeficiency virus (HIV) in health facilities suggests that expansion of HIV testing and counselling (HTC) to non-clinical settings is critical to the achievement of national goals for prevention, care and treatment. Consideration should be given to the ability of lay counsellors to perform home-based HTC in community settings. METHODS: We implemented a community cluster randomized controlled trial of home-based HTC in Sisonke District, South Africa. Trained lay counsellors conducted door-to-door HIV testing using the same rapid tests used by the local health department at the time of the study (SD Bioline and Sensa). To monitor testing quality and counsellor skill, additional dry blood spots were taken and sent for laboratory-based enzyme-linked immunosorbent assay (ELISA) testing. Sensitivity and specificity were calculated using the laboratory result as the gold standard. RESULTS AND DISCUSSION: From 3986 samples, the counsellor and laboratory results matched in all but 23 cases. In 18 cases, the counsellor judged the result as indeterminate, whereas the laboratory judged 10 positive, eight negative and three indeterminate, indicating that the counsellor may have erred on the side of caution. Sensitivity was 98.0% (95% CI: 96.3 98.9%), and specificity 99.6% (95% CI: 99.4 99.7%), for the lay counsellor field-based rapid tests. Both measures are high, and the lower confidence bound for specificity meets the international standard for assessing HIV rapid tests. CONCLUSIONS: These findings indicate that adequately trained lay counsellors are capable of safely conducting high-quality rapid HIV tests and interpreting the results as per the kit guidelines. These findings are important given the likely expansion of community and home-based testing models and the shortage of clinically trained professional staff.Department of HE and Training approved lis

Linear correlation between (A) NucliSens v2.0 versus CAP/CTM v2.0 (B) NucliSens v2.0 versus Amplicor v1.5 (C) CAP/CTM v2.0 versus Amplicor v1.5.

<p>Solid lines represent the fitted linear regression curve, dashed lines show the equality line and dotted lines represent lower limits of detection of the respective assay.</p

Bland-Altman model showing the agreement between (A) NucliSens v2.0 and CAP/CTM v2.0 (B) NucliSens v2.0 and Amplicor v1.5 (C) CAP/CTM v2.0 and Amplicor v1.5.

<p>Dashed horizontal lines show the mean difference and the dotted lines indicate the 95% limits of agreement.</p

Data summary for viral load results as determined by the Amplicor v1.5, NucliSens v2.0 and CAP/CTM v2.0 assay.

<p>Data summary for viral load results as determined by the Amplicor v1.5, NucliSens v2.0 and CAP/CTM v2.0 assay.</p