Real-time, universal screening for acute HIV infection in a routine HIV counseling and testing population

Acute human immunodeficiency virus (HIV) infection cannot be diagnosed by routine antibody tests and is rarely diagnosed in clinical practice. However, HIV nucleic acid-based testing is widely used to screen for antibody-negative acute infection among low-risk blood donors.

To assess the feasibility of screening in high-volume laboratories for acute and long-term HIV infection in a routine HIV testing population, in which HIV infection prevalence is low, using specimen pooling and HIV RNA reverse transcriptase-polymerase chain reaction (RT-PCR) tests.

Clinical diagnostic performance evaluation at a state-funded public health virology and serology laboratory.

A total of 8505 consecutive individuals presenting for routine HIV counseling and testing during a total of 20 business days to simulate a month of testing in August and December 2001 at 110 publicly funded testing sites in North Carolina.

Prevalence of acute and long-term HIV infection. Serum specimens negative by HIV enzyme immunoassay (EIA) were screened in pools by an ultrasensitive HIV RNA RT-PCR test. Results for individual HIV RNA-positive specimens were reclassified as true or false according to results of confirmatory testing.

Of the 8505 individuals screened, 8194 had not previously tested HIV positive and had sufficient serum to complete the testing protocol. Of those, 39 had long-term HIV infection (prevalence, 47.6 per 10,000 at-risk persons [95% confidence interval, 33.8-65.0 per 10,000]). Of the 8155 at-risk individuals whose antibody tests were negative, 5 were HIV RNA positive. Four of those had true-positive acute infection (prevalence, 4.9 per 10,000 [95% confidence interval, 1.3-12.5 per 10,000]). All 4 were women; 2 developed symptoms consistent with an acute retroviral syndrome in the week after testing. Screening all specimens required 147 HIV RNA tests. Overall specificity of the strategy was 0.9999.

These findings suggest the widespread diagnosis of acute HIV infections in a routine testing population is not only possible but feasible using specimen pooling and nucleic acid testing. These additional procedures may increase diagnostic yield by approximately 10% compared with conventional HIV antibody testing.