What lab tests are recommended 1 month after the first cabotegravir (Integrase Strand Transfer Inhibitor) injection for HIV treatment?

Laboratory Testing at 1 Month After First Cabotegravir Injection

At the 1-month follow-up visit, perform HIV testing using both a point-of-care rapid HIV antibody test AND a laboratory-based fourth- or fifth-generation antigen/antibody test. 1

Mandatory HIV Testing Protocol

The most critical testing at this visit is HIV screening, which must include:

• A point-of-care rapid HIV antibody test performed at the visit 1
• A laboratory-based fourth- or fifth-generation antigen/antibody combination test sent for processing 1, 2

This dual testing approach is essential because cabotegravir can delay HIV seroconversion and mask early infection through a phenomenon called LEVI (long-acting early viral inhibition), making single-test strategies inadequate. 1

Why HIV RNA Testing Is NOT Routinely Recommended at This Visit

Do not routinely order HIV RNA testing at follow-up visits for cabotegravir PrEP. 1

• RNA testing for routine monitoring has a low positive predictive value and false-positive results carry significant negative consequences 1
• HIV RNA testing should be reserved for: (1) initial PrEP initiation/resumption after hiatus, or (2) when there is clinical suspicion of acute HIV infection 1
• At routine follow-up visits like this 1-month check, the combination of rapid antibody plus laboratory antigen/antibody testing is sufficient 1

Additional Recommended Testing at This Visit

Beyond HIV testing, assess:

• Pregnancy status if applicable (required baseline testing that should be repeated if pregnancy risk exists) 2
• STI screening at all exposed mucosal sites based on sexual history and exposures 1
• Adherence assessment to the injection schedule 1
• Tolerability evaluation including injection site reactions (which occur in up to 81% but typically diminish over time) 2

Critical Timing Considerations

• This 1-month visit corresponds to the timing of the second cabotegravir injection (the first two injections are separated by 4 weeks) 2, 3
• HIV testing must be completed before administering the second injection 2, 3
• Never skip pre-injection HIV testing even if the patient appears low-risk or was recently tested 3

Common Pitfalls to Avoid

• Do not rely on antibody testing alone - the combination antigen/antibody test is mandatory to detect acute infections that antibody-only tests would miss 2
• Do not proceed with the injection if HIV test results are pending or concerning - wait for definitive negative results 2
• Do not order routine HIV RNA testing at follow-up visits unless there is clinical suspicion of acute infection, as this leads to false positives with harmful consequences 1

What Happens If Seroconversion Is Detected

If HIV infection is detected at this or any follow-up visit:

• Immediately obtain genotypic resistance testing including integrase mutations 3
• Never continue cabotegravir or switch to another integrase inhibitor-based regimen due to high risk of multi-drug resistance 3
• Switch to a protease inhibitor or NNRTI-based antiretroviral regimen 3