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 L of whole blood applied to a paper card, which was then stored at ؊20°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. (HEPATOLOGY 2010;51:752-758.) H epatitis C virus (HCV) infection is currently underdiagnosed, leaving many individuals unaware of their infection status. Some population groups, such as sex workers, the homeless, prisoners, or other institutionalized individuals, have a higher prevalence of HCV infection than the general population. [1][2][3] However, HCV testing in these groups is limited by the poor acceptability or feasibility of venipuncture. Collecting capillary blood spots on filter paper requires less staff training, is less invasive, involves smaller blood volumes, and is ideal for high-risk patients with damaged veins, such as intravenous drug users. 4 In addition, this technique can reduce the cost of HCV testing by simplifying sample collection, processing (no centrifugation), storage, and shipment. Many studies have already demonstrated the value of dried blood spots (DBS) for the serological and molecular diagnosis of human immunodeficiency virus. [5][6][7][8][9][10][11] Routine screening for HCV infection relies on detecting antibodies against HCV (anti-HCV) using highly sensitive second-or third-generation enzyme immunoassay. DBS have been used to detect anti-HCV among intravenous drug users, prisoners and childbearing women. 12-17 However, the diagnosis of acute or chronic infection also requires the detection of HCV RNA by polymerase chain reaction (PCR). 18,19 Likewise, when recent HCV infection is suspected or the patient is immunocompromised, then the sample should be referred for PCR. Samples with a low screening signal-to-cutoff ratio may also need confirmation with these more specific recombinant immunoblot assays. 20,21 In this study, we have investigated both anti-HCV and HCV RNA detecti...

People screened for human immunodeficiency virus (HIV) using rapid diagnostic tests (RDTs) in Africa remain generally unaware of their status for hepatitis B (HBV) and hepatitis C (HCV) infections. We evaluated a two-step screening strategy in Burkina Faso, using both HIV RDTs and Dried Blood Spot (DBS) assays to confirm an HIV-positive test, and to test for HBV and HCV infections. HIV counselling and point-of-care testing were performed at a voluntary counselling and testing centre with HBV, HCV status and HIV confirmation using DBS specimens, being assessed at a central laboratory. Serological testing on plasma was used as the reference standard assay to control for the performance of DBS assays. Nineteen out of 218 participants included in the study were positive for HIV using RDTs. A fourth-generation HIV ELISA and immunoblot assays on DBS confirmed HIV status. Twenty-four out of 25 participants infected with HBV were found positive for hepatitis B surface antigen (HBsAg) using DBS. One sample with a low HBsAg concentration on plasma was not detected on DBS. Five participants tested positive for HCV antibodies were confirmed positive with an immunoblot assay using DBS specimens. Laboratory results were communicated within 7 days to participants with no loss to follow up of participants between the first and second post-test counselling sessions. In conclusion, DBS collection during HIV point-of-care testing enables screening and confirmation of HBV, HCV and HIV infections. Diagnosis using DBS may assist with implementation of national programmes for HBV, HCV and HIV screening and clinical care in middle- to low-income countries.

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.

BackgroundThe 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 FindingsHBsAg 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 log10 IU/mL; −0.57 to 0.64, −0.04 log10 IU/mL; −0.09 to 0.45, −0.27 log10 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/SignificanceThe 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.

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.

Diagnostic of acute hepatitis A virus (HAV) infection is based on the detection of anti‐HAV IgM without testing for the pathogen itself. We evaluated the usefulness of HAV RNA testing for confirmation of acute hepatitis A and to provide indications about the level of HAV replication in HIV‐positive and HIV‐negative subjects during an unprecedented outbreak of HAV observed in France in 2017. HAV RNA was detected in 38 out of 41 (92.6%) subjects with a clinical diagnosis of acute hepatitis A, whereas nine cases tested positive for anti‐HAV IgM in whom the diagnosis of acute hepatitis A was not retained were found negative for HAV RNA. All subjects in the control group were also tested negative for HAV RNA. HAV viremia was correlated to ALT peak (r = .64; P < .0001). HIV‐infected patients have similar HAV RNA levels but were less likely to have prolonged international normalized ratio of prothrombin time when compared to the HIV‐uninfected group (P = .016), suggesting a less severe course of acute hepatitis. HAV RNA was detected in the serum of most of the patients with acute hepatitis A, indicating that the direct detection of HAV can be used to confirm hepatitis A in patients tested positive for anti‐HAV IgM antibodies. Nucleic acid tests should serve more broadly during the diagnosis workup of acute hepatitis A to improve the predictive values of HAV in vitro diagnostic tests and to confirm acute hepatitis A in patients tested positive with IgM with moderate or low S/CO values.

No abstract

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.Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. Therapy is monitored by assessing the kinetics of viral clearance based on HCV RNA quantitation (2,8,12,17). Available commercial kits are based on target amplification technology (reverse transcription-PCR) or on signal amplification (branched DNA). Irrespective of the method, the specificity of the hybridization between probe/primer and target is the determining factor of the method's performance. Polymorphisms within the primer/probe-targeted HCV regions may cause significant losses of performance and compromise the accuracy of viral load (VL) measurements. Based on their natural polymorphism, the HCV viruses have been classified into six major genotypes (GT) (14). Most known GT are found in Europe but with different distribution frequencies in various geographic regions (5).The aim of the present study was to evaluate the performance of the three commercially available HCV RNA quantitative assays, two real-time reverse transcriptase assays, and a signal amplification assay using a panel of serum samples from well-characterized HCV-infected patients with GT1 to GT5.Serum samples were collected during 2005 from 158 consecutive patients residing in Southern France, with HCV infection confirmed by use of a COBAS Amplicor HCV test, version 2.0 (detection limit of 50 IU/ml; Roche Diagnostics, Mannheim, Germany). Each serum sample was divided into three aliquots and stored at Ϫ80°C within 4 h of blood sampling. HCV genotype was determined by using a VERSANT HCV genotyping assay (line probe assay) (Bayer Diagnostics, Tarrytown, NY).All samples were processed in accordance with the manufacturer's instructions. The COBAS Ampliprep/COBAS TaqMan HCV test (CAP/CTM) (Roche Diagnostics, Mannheim, Germany) requires 1,050 l of serum with a sample input volume of 850 l and with a quantification range of 15 to 6.9 ϫ 10 7 IU/ml (1.18 to 7.84 log 10 ). The HCV RealTime assay (antiretroviral therapy [ART]; Abbott Laboratories, Abbott Park, IL) requires 1,000 l of serum, with a quantification range of 12 to 1 ϫ 10 7 IU/ml (1.08 to 7.0 log 10 ). The Abbott ART HCV kit was used in conjunction with the Abbott m1000 extraction and the m2000rt amplification systems. The VERSANT HCV RNA 3.0 (bDNA) assay (Bayer Diagnostics, Tarrytown, NY) requires 50 l of plasma or serum, with a quantification range of 615 to 7.7 ϫ 10 6 IU/ml (2.79 to 6.89 log 10 ) with the VERSANT 340 analyzer.Values outside the quantification ranges were exclude from comparison and correlation analyses. Mean values Ϯ standard deviations (SD) were determined for each method and compared using the Student paired t test for global results. Diffe...