Anne‐Marie Mondain

UNLABELLED: We investigated the performance of dried blood spots (DBS) in hepatitis C virus (HCV) diagnosis using modified commercial tests. Paired DBS and serum samples were collected from 200 patients: 100 patients with anti-HCV antibodies (anti-HCV), including 62 patients with detectable serum HCV RNA, and 100 patients without anti-HCV. The DBS sample consisted of three drops of approximately 50 microL of whole blood applied to a paper card, which was then stored at -20 degrees C within 48 hours of collection. Using the Ortho HCV 3.0 enzyme-linked immunosorbent assay kit on DBS, we observed both a specificity and sensitivity of 99% in detecting anti-HCV. HCV RNA was detected on DBS in 60/62 (97%) patients with detectable serum HCV RNA, which was then successfully quantified in 55 samples (89%) using the Cobas TaqMan HCV test. A good correlation was observed between the DBS HCV RNA concentration and the serum level (r(2) = 0.95; P < 0.001). HCV genotyping was successfully performed on DBS samples, with a full concordance between the 14 paired DBS and serum samples (genotypes 1-4). CONCLUSION: This study presents DBS as a reliable alternative to serum specimens for detecting anti-HCV, quantifying HCV RNA and genotyping HCV. DBS may increase the opportunities for HCV testing and treatment follow-up in hard-to-reach individuals.

BACKGROUND: The decline in hepatitis B virus surface antigen (HBsAg) may be an early predictor of the viral efficacy of Hepatitis B virus (HBV) therapy. The HBsAg levels obtained by different immunoassays now need comparing and the relationships between levels of HBsAg and HBV DNA alongside HBsAg and genotype must be evaluated. METHODOLOGY/PRINCIPAL FINDINGS: HBsAg levels were compared among 80 patients using the Abbott Architect assay, a commercial immunoassay approved for HBsAg detection and quantitation, and three other assays derived from immunoassays approved for HBsAg detection (manufactured by Diasorin, Bio-Rad and Roche). Good correlation was found between the Abbot vs. Diasorin, Bio-Rad and Roche assays with narrow 95% limits of agreement and small mean differences: -0.06 to 0.11, -0.09 log(10) IU/mL; -0.57 to 0.64, -0.04 log(10) IU/mL; -0.09 to 0.45, -0.27 log(10) IU/mL, respectively. These agreements were not affected by genotypes A or D. HBsAg was weakly correlated with HBV DNA, whatever the HBsAg assay used: Abbott, ρ = 0.36 p = 0.001, Diasorin ρ = 0.34, p = 0.002; Bio-Rad ρ = 0.37, p<0.001; or Roche ρ = 0.41, p<0.001. This relationship between levels of HBsAg and HBV DNA seemed to depend on genotypes. Whereas HBsAg (Abbott assay) tended to correlate with HBV DNA for genotype A (ρ = 0.44, p = 0.02), no such correlation was significant for genotypes D (ρ = 0.29, p = 0.15). CONCLUSION/SIGNIFICANCE: The quantitation of HBsAg in routine clinical samples is comparable between the reference assay and the adapted assays with acceptable accuracy limits, low levels of variability and minimum discrepancy. While HBsAg quantitation is not affected by HBV genotype, the observed association between levels of HBsAg and HBV DNA seems genotype dependent.

BACKGROUND: In Africa, most HIV-HBV-coinfected patients on antiretroviral therapy (ART) receive an anti-HBV lamivudine monotherapy that has been shown in northern countries to lead to frequent emergence of drug resistance. We assessed the HBV prevalence and the rate and pattern of lamivudine-resistant HBV mutations in Cameroonian HIV-infected, ART-treated patients. METHODS: A cross-sectional survey was performed in 2006-2007 at the HIV/AIDS outpatient clinic of the Central Hospital in Yaoundé, Cameroon. Plasma samples were tested as appropriate for hepatitis B surface antigens, antibodies to hepatitis B core, HBV DNA, genotypes and lamivudine-resistant polymerase mutations. RESULTS: Of 552 adult patients (71% women, median age 38 years), 290 had received lamivudine-based ART for 12 months and 262 for 24 months. No patient had received tenofovir. The prevalence of hepatitis B surface antigen was 9.8%. Overall, 26% of seropositive patients had an HBV DNA level >40 IU/ml. Genotypes A and E were identified. Polymerase resistance mutations were detected in 14% and 60% of patients at months 12 and 24, respectively. CONCLUSIONS: This study supports both WHO recommendations of screening for HBV before initiation of ART and of using ART containing tenofovir and either lamivudine or emtricitabine in HIV-HBV-coinfected patients in Africa.

Abstract The implementation of rapid diagnostic tests (RDTs) may enhance the efficiency of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) testing, as RDTs are widely accessible and easy to use. The aim of this study was to evaluate the performance of a diagnosis strategy based on a combination of antigen and immunoglobulin M (IgM) or immunoglobulin G (IgG) serological RDTs. Plasma and nasopharyngeal samples were collected between 14 March and 11 April 2020 at hospital admission from 45 patients with reverse transcription polymerase chain reaction (RT‐PCR) confirmed COVID‐19 and 20 negative controls. SARS‐CoV‐2 antigen (Ag) was assessed in nasopharyngeal swabs using the Coris Respi‐Strip. For IgM/IgG detection, SureScreen Diagnostics and Szybio Biotech RDTs were used in addition to laboratory assays (Abbott Alinity i SARS‐CoV‐2 IgG and Theradiag COVID‐19 IgM enzyme‐linked immunosorbent assay). Using the Ag RDT, 13 out of 45 (29.0%) specimens tested positive, the sensitivity was 87.0% for cycle threshold ( C t ) values ≤25% and 0% for C t values greater than 25. IgG detection was associated with high C t values and the amount of time after the onset of symptoms. The profile of isolated IgM on RDTs was more frequently observed during the first and second week after the onset of symptoms. The combination of Ag and IgM/IgG RDTs enabled the detection of up to 84.0% of COVID‐19 confirmed cases at hospital admission. Antigen and antibody‐based RDTs showed suboptimal performances when used alone. However when used in combination, they are able to identify most COVID‐19 patients admitted in an emergency department.

The VERSANT HCV RNA 3.0 (bDNA), COBAS AmpliPrep/COBAS TaqMan HCV, and Abbott ART HCV RealTime assays were compared for hepatitis C virus RNA quantification in 158 clinical specimens (genotypes 1 to 5). RNA values differed significantly between methods (P < 0.0001), and mean titer differences ranged from 0.01 to 0.50 log(10) IU/ml depending on the genotypes.