ABSTRACT
Point-of-Care for HIV viral RNA quantification seems to be a complementary strategy to the existing conventional systems. This study evaluated the performance of the m-PIMA™ HIV1/2 Viral Load for the quantification of both HIV-1 and HIV-2 RNA viral load. A total of 555 HIV-1 and 90 HIV-2 samples previously tested by Abbott RealTime HIV-1 (Abbott, Chicago, USA) and Generic HIV-2® Charge virale (Biocentric, France) were tested using the m-PIMA™ HIV1/2 Viral Load at the HIV National Reference lab in Senegal. For HIV-1, Pearson correlation and Bland-Altman plots showed a coefficient r = 0.97 and a bias of -0.11 log10 copies/ml (95% confidence interval [CI]: -0.086 to -0.133 log10 copies/ml) for the m-PIMA™ HIV1/2 Viral Load, respectively. Sensitivity and specificity at 3 log10 copies/ml (threshold of virological failure) were 93.6% (95%[CI]: 91.5% to 95.6%) and 99.1% (95%[CI]: 98.3% to 99.9%), respectively. For HIV-2, a correlation of r = 0.95 was also noted with a bias of - 0.229 log10 copies/ml (95%[CI]: -0.161 to -0.297 log10 copies/ml). Sensitivity and specificity at 3 log10 copies/ml were 97.6% (95%[CI]: 94.3% to 100%) and 93.9% (95%[CI]: 88.9% to 98.8%), respectively. These results confirmed that m-PIMA™ HIV1/2 VL could be a good alternative for HIV-1 and HIV-2 viral load testing in decentralized settings in Senegal.
Subject(s)
HIV Infections , HIV-1 , Humans , HIV-1/genetics , HIV-2/genetics , HIV Infections/diagnosis , Viral Load/methods , Sensitivity and Specificity , Africa, Western , RNA, Viral/geneticsABSTRACT
Introduction: early infant diagnosis (EID) is crucial in the prevention of mother to child transmission (PMTCT) of human immunodeficiency virus (HIV) and is an essential component for the elimination of HIV. EID can be strengthened in resource-limited countries by the introduction and the roll out of real-time polymerase chain reaction (PCR) technologies via point-of-care (POC) devices which improves treatment in remote areas and reduces turnaround time for clinicians and patients to receive results and linkage to care. The objective of this study was to evaluate the performance of Xpert® HIV-1 Qual Assay (Cepheid) and m-PIMA™ HIV 1/2 Detect (ABBOTT) for EID of HIV-1 and HIV-2. Methods: the performance of the Xpert® HIV-1 qual device was evaluated with 192 samples including 100 dried blood spot (DBS) samples from the National Reference Laboratory biobank (71 negative and 29 positive samples) and an additional 92 whole blood samples collected from infants from neonatal departments. These infants from seven treatment centers in the Dakar region were born to mothers infected with HIV-1 (n=91), HIV-2 (n= 8) or HIV-1/2 (n=1). The m-PIMA™ HIV 1/2 detect assay was evaluated on whole blood samples (n=100) with 92 HIV-1 samples and 8 HIV-2 samples from children born to HIV-infected mothers. The Cobas AmpliPreP/Cobas TaqMan (CAP/CTM) platform from Roche Diagnostic Laboratories was used as a reference for HIV-1 diagnosis and the Generic HIV-2 Viral Load Assay (Biocentric) was used as a reference for HIV-2 diagnosis. Performance was evaluated by calculating sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and Cohen's kappa coefficient. Results: for HIV-1 detection on GeneXpert and m-PIMA, no discordance was found on the samples tested, i.e. a sensitivity of 100% (95% CI: 93.9-100%), a specificity of 100% (95% CI: 97.5-100%), a positive predictive value (PPV) of 100% (95% CI: 93.9-100%) and a negative predictive value (NPV) of 100% (95% CI: 97.5-100%). Agreement with Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) was 100% with a Kappa coefficient of 1 (p<0.001, 95% CI) for both techniques. Similarly, the comparison between m-PIMA and generic biocentric for the detection of HIV-2 on the 8 samples tested showed perfect agreement. Conclusion: these results confirm the excellent performance of the Xpert® HIV-1 qual and m-PIMA™ HIV1/2 detect tests for the detection of HIV-1 and HIV-2 and encourage the extension of POC tests to improve access to EID in Senegal.
Subject(s)
HIV Infections , HIV-1 , Infant , Infant, Newborn , Child , Humans , Female , HIV-1/genetics , HIV-2 , Potassium Iodide , Point-of-Care Systems , Senegal , Infectious Disease Transmission, Vertical , Sensitivity and Specificity , Early Diagnosis , Viral Load , RNA, ViralABSTRACT
Introduction: the introduction of the point-of-care in HIV-1 viral load quantification appears to be a complementary strategy to the existing conventional system of the acceleration plan for the achievement of the three 90s in Senegal. The objective of this study was to evaluate the performance of the Xpert® HIV-1 viral load in the context of circulation of non-B, non-C subtypes. Methods: two hundred samples, were tested on Xpert® HIV-1 Viral Load using 1 ml of plasma in comparison to 600 µl on Abbott Real-time HIV-1 assay. The difference between viral load values was considered significant for Dlog <0.5 log copies/ml. Results: a good correlation (r=0.985) was noted and confirmed using passing-bablok regression (slope 1.048; 95% CI: 1.036 to 1.069) for 188 samples with samples. A mean difference of 0.0075 log10 copies/ml for a 95% confidence interval (CI) of 0.002 log10 copies/ml to 0.013 log10 copies/ml was obtained. Sensitivity and specificity were respectively 93.6% and 93.5% at the threshold of 1.6 log10 copies/ml and 100% and 99% at the threshold of 3.0 log10 copies/ml. Conclusion: these results show that Xpert® HIV-1 Viral Load has excellent performance. In Senegal, and can be used for HIV viral load monitoring.
