BACKGROUND: Fourth generation assays detect simultaneously antibodies for HIV 
and the p24 antigen, identifying HIV infection earlier than previous generation 
tests. Previous studies have shown that the Alere Determine HIV-1/2 Combo has 
lower than anticipated performance in detecting antibodies for HIV and the p24 
antigen. Furthermore, there are currently very few studies evaluating the 
performance of Standard Diagnostics BIOLINE HIV Ag/Ab Combo.
OBJECTIVE: To evaluate the performance of the Alere Determine HIV-1/2 Combo and 
the Standard Diagnostics BIOLINE HIV Ag/Ab Combo in a panel of frozen serum 
samples.
STUDY DESIGN: The testing panel included 133 previously frozen serum specimens 
from the UCLA Clinical Microbiology & Immunoserology laboratory. Reference 
testing included testing for HIV antibodies by a 3rd generation enzyme 
immunoassay followed by HIV RNA detection. Antibody negative and RNA positive 
sera were also tested by a laboratory 4th generation HIV Ab/Ag enzyme 
immunoassay.
RESULTS: Reference testing yielded 97 positives for HIV infection and 36 
negative samples. Sensitivity of the Alere test was 95% (88-98%), while the SD 
Bioline sensitivity was 91% (83-96%). Both assays showed 100% (90-100%) 
specificity. No indeterminate or invalid results were recorded. Among 13 samples 
with acute infection (HIV RNA positive, HIV antibody negative), 12 were found 
positive by the first assay and 8 by the second. The antigen component of the 
Alere assay detected 10 acute samples, while the SD Bioline assay detected only 
one.
CONCLUSIONS: Both rapid assays showed very good overall performance in detecting 
HIV infection in frozen serum samples, but further improvements are required to 
improve the performance in acute infection.