HIV Testing Protocol When PEP is Not Used
If Post-Exposure Prophylaxis (PEP) is not used following HIV exposure, perform HIV antibody testing at baseline, 6 weeks, 12 weeks, and 6 months post-exposure using standard enzyme immunoassay (EIA) testing. 1
Testing Schedule Without PEP
The standard follow-up protocol for exposed individuals who do not receive PEP consists of:
- Baseline testing: Immediately after exposure to establish HIV status 1
- 6 weeks post-exposure: First follow-up test 1
- 12 weeks post-exposure: Second follow-up test 1
- 6 months post-exposure: Final test to definitively rule out HIV infection 1
This 6-month testing window captures the vast majority of seroconversions, as most HIV-infected persons will develop detectable antibodies within this timeframe. 1
Testing Methodology
Use HIV-antibody testing with enzyme immunoassay (EIA) as the standard approach for monitoring seroconversion. 1 The guidelines explicitly state that routine use of direct virus assays (such as HIV p24 antigen EIA or tests for HIV RNA) is not recommended for routine follow-up when PEP is not used. 1 The rationale is that these direct assays have high false-positive rates in this setting, leading to unnecessary anxiety and potentially inappropriate treatment, while only detecting infection a few days earlier than standard antibody testing. 1
For initial baseline testing, a rapid antibody or antigen-antibody test is preferred to expedite results, but this should be followed by laboratory-based confirmation. 1
Critical Exception: Acute Retroviral Syndrome
Perform immediate HIV testing on any exposed person who develops an illness compatible with acute retroviral syndrome, regardless of the time interval since exposure. 1 This is a crucial safety net, as acute HIV infection can present with flu-like symptoms (fever, rash, lymphadenopathy, pharyngitis) and represents a period of extremely high viral load and infectivity. Do not wait for the scheduled testing intervals if clinical symptoms suggest acute infection. 1
Extended Follow-Up Considerations
The guidelines acknowledge that extended follow-up beyond 6 months (e.g., to 12 months) has been suggested in certain circumstances, particularly for simultaneous exposure to HCV or when highly potent antiretroviral regimens were used (though this applies when PEP was given). 1 However, the evidence does not support routine extension of follow-up to 12 months when no PEP is used, as delayed seroconversion beyond 6 months is extremely rare and does not justify the added anxiety for exposed individuals. 1
Clinical judgment may warrant extended follow-up in individual cases, but this should be the exception rather than the rule. 1
Counseling and Prevention Measures
During the 6-month follow-up period, exposed individuals should receive counseling about:
- Secondary transmission prevention: Use sexual abstinence or condoms, especially during the first 6-12 weeks when most seroconversions occur 1
- Pregnancy avoidance during the follow-up period 1
- Importance of completing all follow-up testing even if earlier tests are negative 1
Key Pitfall to Avoid
The most common error is using expensive direct virus assays (HIV RNA or p24 antigen tests) for routine follow-up when PEP is not used. 1 These tests are not recommended because they provide minimal benefit (detecting infection only days earlier) while significantly increasing costs and false-positive results. 1 Reserve these assays only for cases where acute retroviral syndrome is clinically suspected. 1
The simplified testing protocol without PEP—baseline, 6 weeks, 12 weeks, and 6 months using standard antibody testing—provides adequate surveillance for HIV seroconversion while minimizing unnecessary testing costs and patient anxiety. 1