Unique Testing Experience for Acute HIV Infection: The Dallas County NAAT Program

Background:  Routine antibody assays for HIV-1 are usually nonreactive during the first four to five weeks after infection.  Dallas County Health and Human Services (DCHHS) integrated HIV-1 RNA Qualitative Assay, an HIV-1 Nucleic Acid Amplification Test (NAAT), in July 2009 making possible detection of HIV-1 within two weeks of infection.  This testing methodology is critical in HIV prevention as individuals are the most infectious during the acute stage.

Objectives:  To describe how DCHHS implemented the NAAT assay alongside the standard HIV antibody assays for detecting an Acute HIV infection (AHI).

Methods:  DCHHS laboratory tested patients for AHI using the NAAT assay.  The specimens are pooled together in pools of 10.  A reactive pool is broken down and each specimen is tested individually.  A reactive result is available within 3 days of collection.

Results:  A total of 56 NAAT reactive specimens were detected out of 55,717 specimens analyzed.  The antibody assay (EIA) did not detect any antibodies for HIV on 64% (36/56) of the NAAT reactive specimens.  The remaining 36% (20/56) NAAT reactive specimens were reactive on the antibody assay with a nonreactive or indeterminate Western Blot result. Additional STDs occurring with NAAT reactive were: 45% no other STDs; 21% Syphilis; ~14% other STDs excluding Syphilis (example: Neisseria gonorrhoeae); 20% unknown (due to patient confidentiality).

Conclusions:  Improving the detection of an AHI is crucial for HIV prevention. Without the advancement in technology 56 patients could have received a negative or indeterminate test result prior to the NAAT resulting in a delay in diagnosis and potential spread to uninfected partners.  We feel the increase in detection of an AHI warrants implementing the new technology for HIV-1 detection. 

Implications for Programs, Policy, and Research:  The NAAT Testing has provided an opportunity for the STD/HIV Program to inform patients infected with HIV and provide them with medical services in the early stages of the disease.