Assessment of the performance of six in vitro diagnostic kits for qualitative detection of hepatitis B virus surface antigen (HBsAg) in human serum or plasma in Lomé, Togo

Background: Several in vitro diagnostic (IVD) test kits for hepatitis B surface antigen (HBsAg) are commercially available. The question is whether they are performing well for both screening and diagnosis or not? Thus, this study aimed to evaluate the performance of six commercially available HBsAg detection kits in Togo. Methods: This study was conducted at the National Reference Center for HIV/STI testing in Lomé (CNR-VIH/IST), Togo. Reference sera used for the assessment were collected from blood donors and patients with history of hepatitis B viral (HBV) infection between 2008 and 2014, and includes 200 non-reactive HBsAg and 150 reactive HBsAg sera that were confirmed with a reference method which consisted of the combination of an ELISA, a RDT, and a molecular test. Four ELISA kits (EKOlab ELISA-HBsAg; HEPALISA ULTRA; HEPALISA; Murex AgHBs Version 3) and two RDTs kits (ACON AgHBs and OnSite HBsAg Rapid Test-Cassette) were then evaluated using these serum samples. The EPI-INFO software version 7.2 was used to determine the 95% confidence interval and performed statistical analysis. Results: Reference serum samples were collected from the population with 65.0% under 40 years of age and 61.2% males. The sensitivity of the 4 ELISA tests compared to the reference method was 100%. Apart from the HEPALISA test with a specificity of 100.0%, the specificity of the other three ELISA tests (Murex HBsAg version 3, HEPALISA ULTRA and EKOlab ELISA-HBsAg) were 98.4%, 97.3% and 91.8% respectively. For the RDTs, the sensitivity of ACON HBsAg and OnSite HBsAg Rapid Test-Cassette was 70.0% and 95.6% respectively while the specificity was 100.0% for both. Conclusion: The ELISA tests evaluated were more sensitive than the RDTs, and HEPALISA test was the most efficient. Of the two RDTs, the OnSite HBsAg Rapid Test-Cassette was more sensitive. Our findings highlight the need for onsite verification of in vitro diagnostic kits for qualitative detection of hepatitis B surface antigen before their routine use in Togo. Keywords: HBV, HBsAg, Performance, IVD tes

Performance of the biomerieux DBS puncher and dried blood spots to measure HIV-1 viral load by real-time nuclisenseasyq HIV-1 assay

Introduction: The latest World Health Organization recommendations request viral load (VL) testing, if possible, for monitoring HIV-1 infections. However, the use of plasma is an obstacle to realize this test in sub-Saharan Africa. In this context, the dried blood spot (DBS) is an interesting tool for sample collections. The objective of this study was to assess the performance of, the bioMérieux PUNCHER a new toolfor cutting DBS.Methods: Plasma and DBS samples were obtained from 102 patients, with17 HIV-1 negative patients and 85 HIV-1 infected patients (58% were antiretroviral therapy naïve). DBS were stored at room temperature for 15 days before testing. The PUNCHER’s performance used to cut DBS was evaluated with following criteria: contamination, time of cut and VL measurement. VL was measured in parallel on plasma and DBS samples using NucliSENS EasyQ HIV-1.Results: No contamination was observed with negative samples. Sixty two DBS were cut in one hour. The correlation between plasma and DBS results was strong (R = 0.91; P< 0.001). According to Bland-Altman approach the mean of differences was [-0.59 ± 0.65] log10 copies/ml.Conclusions: PUNCHER is highly efficient at cutting DBS, and the VL results from DBS correlated well with those obtained from plasma. bioMérieux puncher can be used to cut DBS for HIV-1 diagnosis and virological monitoring.Keywords: DBS, bioMérieux puntcher, performance, Viral loa