Follow-Up Testing for Cabotegravir PrEP
For patients initiated on cabotegravir PrEP, follow-up HIV testing should NOT routinely include HIV-1 RNA testing, but rather should use rapid HIV antibody testing and laboratory-based antigen/antibody testing at each injection visit (every 8 weeks after the initial 4-week interval), with STI testing performed every 4 months (at every second injection). 1
HIV Testing Schedule for Cabotegravir PrEP
Routine HIV Monitoring
- Rapid point-of-care HIV antibody test should be performed on the day of each injection (every 8 weeks after initial 4-week interval) prior to administering the injection 1
- Laboratory-based antigen/antibody test should be sent simultaneously but injections should not be delayed pending results 1
- HIV RNA testing is NOT recommended as part of routine monitoring for cabotegravir PrEP because it has low positive predictive value and false-positive results have significant negative consequences 1
Critical Distinction from Oral PrEP
This represents a fundamental difference from tenofovir-based oral PrEP, where HIV RNA testing may be included at initiation if there's concern for acute infection, and antigen/antibody testing is repeated at 1 month if RNA testing wasn't available initially 1. The rationale for avoiding routine RNA testing with cabotegravir relates to the phenomenon of "LEVI" (long-acting early viral inhibition), where cabotegravir can cause delayed and inconsistent detection of viremia, antigen, and antibodies 1.
STI Testing Schedule
- STI testing should be performed every 4 months (at every second injection visit) 1
- This includes genital and non-genital gonorrhea and chlamydia testing by nucleic acid amplification test (NAAT) 1
- Syphilis testing should also be performed at these intervals 1
Additional Monitoring
- Liver enzyme tests should be administered every 6 months for patients on cabotegravir PrEP 1
- Pregnancy testing for individuals of childbearing potential should be performed at the same intervals as STI testing 1
Important Caveats
If Breakthrough Infection Suspected
If HIV acquisition is suspected during cabotegravir PrEP, two sequential testing results showing HIV RNA detection at any level (even below the limit of quantification) is highly predictive of true HIV infection 1. This is when RNA testing becomes clinically valuable—for diagnostic confirmation, not routine screening.
Missed Injection Protocol
If an injection is 8 or more weeks late from its due date, HIV testing must be completed before resuming, and the first two injections should again be separated by 4 weeks before returning to the 8-week interval 1.
Based on the evidence provided, none of the answer choices (A, B, C, or D) accurately reflect current guidelines for cabotegravir PrEP monitoring. The correct approach is HIV testing at each injection visit (every 8 weeks after initial 4-week interval) without routine RNA testing, and STI testing every 4 months 1.