High false hepatitis C antibody positivity rate in a regionally-inclusive population of non-renumerated blood donors in Uganda

Abstract

Background: Successful elimination of hepatitis as a public health threat by 2030 will partly rely on the availability and accessibility of affordable accurate disease testing platforms. In the past, testing of hepatitis C virus (HCV) in low resource settings of sub-Saharan Africa (SSA) has relied on anti-HCV testing using rapid diagnostic tests, chemiluminescent microparticle immunoassay (CMIA) and Enzyme-linked Immunosorbent Assays (ELISA) whose diagnostic accuracy has been sub-optimal. We determined the false positivity rate of a CMIA platform that is routinely used to screen donor blood for anti-HCV in Uganda.

Methods: 1,216 CMIA-screened anti-HCV-positive blood donor samples at four regional Ugandan blood banks, were subjected to a third generation ELISA and subsequently to nucleic acid testing (NAT).

Results: Of the above 1,216 samples, 1,122 (92.2%) were negative on ELISA and thus deemed false positives. Active infection (NAT positive) was detected in 98 (8.0%). Presumed resolved infection was recorded among 3 (3.2%) of participants that remained positive on the ELISA platform but negative on NAT.

Conclusion: The Architect CMIA assay exhibited very low specificity for anti-HCV testing. In this context, this finding may suggest need to employ testing protocols that include NAT or a combination of tests with higher validity.

Keywords: High false hepatitis C; Uganda; antibody positivity rate; non-renumerated blood donors.

Figure 1

Hepatitis C virus results following repeat (ELISA anti-HCV) and subsequent (HCV nucleic acid) testing *Presumed false positives: Positive on blood bank CMIA, negative on ELISA testing n=1122 (92.2%) **Active infection: Positive for HCV RNA on NAT testing n=98 (8.0%) regardless of the anti-HCV test result. Positive on both CMIA and NAT testing n=98 (8.0%), ELISA and NAT n=91 (7.4%), negative on ELISA but positive on NAT testing n=7/1122 (0.62%). ***Resolved infection: Positive on reference lab ELISA, negative on NAT testing n=3/94 (3.2%)