Detection of Early Sero-Conversion HIV Infection Using the INSTI^TM HIV-1 Antibody Point-of-Care Test

Abstract

We compared the INSTI^TM HIV-1 Antibody Point-of-Care (POC) Test to laboratory-based tests for detection of early sero-conversion (i.e. acute) HIV infections. Fifty-three (53) individuals with early HIV infection, (i.e. 3^rd generation anti-HIV EIA non-reactive or reactive, HIV-1 Western Blot non-reactive or indeterminate and HIV-1 p24 antigen reactive) were tested by INSTI^TM. The INSTI^TM test was reactive for 34/49 (sensitivity 69.4%; 95% confidence interval 54.6-81.8%) early-infected individuals whose laboratory-based 3^rd generation HIV EIA test was reactive. Four (4) were non-reactive by both the laboratory-based EIA and INSTI^TM tests, but were p24 antigen reactive. The INSTI^TM POC test performs well compared with other POC tests for the detection of early sero-conversion HIV infection, but it may miss 20% to 30% of those detected by laboratory-based 3^rd generation anti-HIV tests. Both POC and laboratory-based anti-HIV tests will fail to detect a proportion of infected individuals in the first weeks after infection.