Background:
Acute HIV infection is rarely diagnosed in clinical practice and missed by standard antibody tests up to six months after initial infection. During this period transmission risk is enhanced due to combination of high-grade viremia, lack of awareness of HIV infection, relative physical health, and ongoing substance use and/or sexual risk behavior. Advantages of early diagnosis includes prevention of the spread of HIV and early treatment which may improve the long-term prognosis.

Objective:
Pooling blood samples from clients screened for syphilis, and testing for HIV-1 RNA for identification of early HIV infection cases.

Method:
The data analyzed from September 2004 to December 2005 of STD program who screened 1553 clients at risk for HIV infection who consented to HIV testing using OraQuick HIV Test and Nucleic Acid Amplification assay (NASBA and bDNA) on pooled samples. Pooling technique involved combining samples of 20 OraQuick negative blood serum to make one large pool in a pyramid structure. By testing a pooled sample, the HIV-1 negative status was confirmed. If the pooled sample contained HIV virus, smaller pools were tested down to an individual client sample.

Result:
Of the 1553 individuals screened, 33% were between ages 30-39, 40% White, 43% Black, 10 % Latino and 4.1% tested positive using OraQuick HIV test kits. The use of NAATs on pooled samples made it possible to identify 6 (0.5%) viremic but antibody-negative clients. The clients were informed, had the test repeated, and they entered into care.

Conclusion:
NAATs assay on pooled blood samples in STD settings allows for early diagnosis of HIV infection and eliminates the HIV sero-conversion “window period”. This improves the diagnostic quality of the HIV/STD clinics, reduces HIV transmission rates by quickly identifying antibody (-) viremic clients, creates opportunities for targeted treatment strategies, prevention and surveillance activities.

Implications:
NAATs could modify the standard algorithm of HIV Diagnosis.