HIV-1 diagnosis using dried blood spots from patients in Kinshasa, DRC: a tool to detect misdiagnosis and achieve World Health Organization 2030 targets.

INTRODUCTION: Currently, only 54% of the population of the Democratic Republic of the Congo (DRC) know their HIV status. The aim of this study was to detect HIV misdiagnosis from rapid diagnostic tests (RDT) and to evaluate serological immunoassays using dried blood spots (DBS) from patients in Kinshasa, DRC. METHODS: Between 2016 and 2018, 365 DBS samples were collected from 363 individuals and shipped to Spain. The samples were from people with a new HIV positive (n = 123) or indeterminate (n = 23) result, known HIV-positive patients (n = 157), and a negative control group (n = 62). HIV serology was performed using Elecsys HIV combi PT (Roche), VIDAS HIV Duo Quick (BioMérieux), and Geenius (Bio-Rad). In addition, HIV RNA detection was performed in all samples using the COBAS AmpliPrep/COBAS Taqman HIV-1 Test 2.0 (Roche). RESULTS: Overall, 272 samples were found to be positive and 93 to be negative for HIV serology. The sensitivity was 100% for both Elecsys and VIDAS techniques, but specificity was slightly higher for the VIDAS test: 100% (96.1-100%) vs 98.9% (94.1-99.9%). Of the 23 indeterminate cases using RDT, only three cases were true-positives with a detectable viral load. Eleven samples out of the 280 classified as positive by RDT corresponded to nine patients who had received a false diagnosis of HIV through RDT (3.9%); six of them had been on antiretroviral therapy for at least 2 years. CONCLUSIONS: Elecsys HIV combi PT and VIDAS HIV Duo Quick immunoassays showed high sensitivity and specificity when using DBS. RDT-based serological diagnosis can lead to HIV misdiagnosis with personal and social consequences in sub-Saharan Africa.

HCV Diagnosis and Sequencing Using Dried Blood Spots from Patients in Kinshasa (DRC): A Tool to Achieve WHO 2030 Targets.

The World Health Organization has established an elimination plan for hepatitis C virus (HCV) by 2030. In Sub-Saharan Africa (SSA) access to diagnostic tools is limited, and a number of genotype 4 subtypes have been shown to be resistant to some direct-acting antivirals (DAAs). This study aims to analyze diagnostic assays for HCV based on dried blood spots (DBS) specimens collected in Kinshasa and to characterize genetic diversity of the virus within a group of mainly HIV positive patients. HCV antibody detection was performed on 107 DBS samples with Vidas® anti-HCV and Elecsys anti-HCV II, and on 31 samples with INNO-LIA HCV. Twenty-six samples were subjected to molecular detection. NS3, NS5A, and NS5B regions from 11 HCV viremic patients were sequenced. HCV seroprevalence was 12.2% (72% with detectable HCV RNA). Both Elecsys Anti-HCV and INNO-LIA HCV were highly sensitive and specific, whereas Vidas® anti-HCV lacked full sensitivity and specificity when DBS sample was used. NS5B/NS5A/NS3 sequencing revealed exclusively GT4 isolates (50% subtype 4r, 30% 4c and 20% 4k). All 4r strains harbored NS5A resistance-associated substitutions (RAS) at positions 28, 30, and 31, but no NS3 RAS was detected. Elecsys Anti-HCV and INNO-LIA HCV are reliable methods to detect HCV antibodies using DBS. HCV subtype 4r was the most prevalent among our patients. RASs found in subtype 4r in NS5A region confer unknown susceptibility to DAA.