Sensitivity of hepatitis C virus core antigen and antibody combination assays in a global panel of window period samples

Abstract

BACKGROUND Hepatitis C virus (HCV) antigen and antibody combination assays have been launched as a cost-effective alternative to nucleic acid testing (NAT) for reducing the antibody-negative window period (WP). Later, a HCV antigen chemiluminescence immunoassay (CLIA) became available. STUDY DESIGN AND METHODS A panel composed of 337 HCV NAT–yield samples that were characterized for viral load (VL) and genotype was used to compare the sensitivity of two combination enzyme-linked immunosorbent assays (Monolisa, Bio-Rad; and Murex, formerly Abbott) and a HCV antigen CLIA (Abbott). Analytic sensitivity was compared with HCV RNA detection using Ultrio (Grifols) by testing serial dilutions of 10 genotype (gt)1 to gt4 samples. RESULTS HCV antigen CLIA detected 92.4% of samples, whereas Monolisa and Murex detected 38.3 and 47.5%, respectively. In the HCV RNA VL range of 105 to 107 IU/mL, Monolisa and Murex detected 38% to 56% of gt1, 85% to 78% of gt2, and 21% to 37% of gt3. The overall geometric mean 50% limit of detection (range) of Ultrio on gt1 to gt4 dilution series was 3.5 (1.2–7.7) copies/mL, compared to 3.3 × 106 (4.4 × 105-2.7 × 107), 3.4 × 106 (2.2 × 105–4.2 × 107), and 2728 (415–7243) copies/mL for Monolisa, Murex, and HCV antigen CLIA, respectively. CONCLUSION Analytical sensitivity of NAT was on average 1 million- and 780-fold higher than combination assays and HCV antigen CLIA, respectively. Relative sensitivities of combination assays differed for genotypes with Murex being more sensitive for gt1 and gt3 and Monolisa more sensitive for gt2. Although being less sensitive than NAT, combination assays could be considered in resource-limited settings since they detect 38% to 47% of seronegative WP donations.

What weighs more—low compliance with self‐deferral or minor medical procedures? Explaining the high rate of hepatitis C virus window‐period donations in Poland

“…Of the 105 HCV NAT‐only–positive infections identified between 2002 and 2014, 32 cases (30%) were included in the study in addition to 15 (7%) repeat donors out of an estimated 220 donations with documented HCV antibody seroconversion over the last 12 months. More background on the laboratory findings, including genotypes and viral loads of HCV WP infections, can be found elsewhere …”

“…More background on the laboratory findings, including genotypes and viral loads of HCV WP infections, can be found elsewhere. 4,23,24 Compared with all HCV NAT-only-positive infections identified at the time of the study, the enrolled cases were similar in terms of mean age (29 vs. 28 years; p 5 0.648), the percentage of men (91% vs. 87%; p 5 0.395), and firsttime donation status (15% vs. 23%; p 5 0.261).…”

Inclusion of human immunodeficiency virus Type 2 (HIV‐2) in a multiplex transcription‐mediated amplification assay does not affect detection of HIV‐1 and hepatitis B and C virus genotypes: a multicenter performance evaluation study

“…For that reason the genotype standards in our multicenter study were cross‐calibrated in copies/mL in multiple (six to 12 or more) bDNA (multiprobe) assays against secondary Sanquin standards . The sponsor of the present multicenter study of the Ultrio Elite/Panther System (Grifols) selected some of the genotype dilution panels that had been already tested in Ultrio and Ultrio Plus . As expected the 50% LODs were comparable to those in Ultrio Plus and varied between 2.5 and 5.3 copies/mL for HBV genotypes, 0.9 and 3.2 copies/mL for HCV genotypes, and 0.7 and 2.0 for HIV‐1 Group M subtypes (Table ).…”

“…To demonstrate subgenotype inclusivity in the Ultrio Elite assay the 100 copies/mL panels for HBV and HIV‐1 genotypes were tested in a 1:4 dilution (equivalent to 25 copies/mL) in four replicates and the data were compared with the 95% and 50% limits of detection (LODs) in the Ultrio (Plus) assays (at the time of preparation of this manuscript the testing of the 100 copies/mL HCV subgenotype reference panels had not yet been performed). The 100 copies/mL BQC genotype reference panels contain the same standards as used for estimating the LODs in the present and earlier analytical sensitivity studies . But were expanded for HIV‐1 with additional genotypes, CRFs, and group O samples and for HBV with dilutions of the WHO HBV DNA genotype panel .…”

“…The 100 copies/mL BQC genotype reference panels contain the same standards as used for estimating the LODs in the present and earlier analytical sensitivity studies. 1,[7][8][9] But were expanded for HIV-1 with additional genotypes, CRFs, and group O samples and for HBV with dilutions of the WHO HBV DNA genotype panel. 10 For calibration in copies/mL of the standards of the WHO HBV DNA genotype panel we compared the bDNA 3.0 results provided by Chudy and colleagues 10 with those obtained in six replicate bDNA assays on dilutions by BQC and since these were in agreement both data sets were used for the final quantification (data not shown).…”