Is bloodwork necessary every three months while on Pre-Exposure Prophylaxis (PrEP)?

Is Bloodwork Necessary Every Three Months While on PrEP?

Yes, HIV testing is mandatory every three months, but renal function testing can be performed every 6 months for most patients. 1, 2

HIV Testing Requirements

• HIV antibody/antigen testing must be performed every 3 months without exception, and PrEP prescriptions should not exceed 90 days without interval HIV testing 1, 2, 3
• This quarterly HIV testing schedule is non-negotiable because PrEP can prolong seroconversion stages and mask symptoms of primary HIV infection, potentially complicating diagnosis 4
• If PrEP has been discontinued for 7 or more consecutive days, repeat combined HIV antibody/antigen testing is required before restarting 2, 3

Renal Function Monitoring

• Creatinine assessment may be performed every 6 months for most patients, not necessarily every 3 months 1, 2
• More frequent renal monitoring (every 3-6 months) is warranted for high-risk patients, including those aged >50 years, taking hypertension or diabetes medications, or with estimated glomerular filtration rates at threshold 1, 2
• PrEP is associated with increased risk of renal adverse events (relative risk 1.43), though most are mild and reversible 5

STI and Other Laboratory Testing

• STI screening (gonorrhea, chlamydia, syphilis) should be performed quarterly at the same time as HIV testing 1, 2
• Hepatitis C antibody testing is recommended annually for most patients, or every 3-6 months for people who inject drugs, MSM using recreational drugs during sex, or those with elevated transaminases 2
• Pregnancy testing should be performed quarterly for individuals of childbearing potential 2, 3

Critical Monitoring Schedule Summary

The first follow-up should occur within 30 days of PrEP initiation, then every 3 months thereafter 1

At each quarterly visit, the following are required:

• HIV antibody/antigen test (mandatory) 1, 2
• STI screening (gonorrhea, chlamydia, syphilis) 1, 2
• Pregnancy testing if applicable 2
• Assessment of adherence, side effects, and risk behaviors 1

At 6-month intervals (can coincide with quarterly visits):

• Renal function testing (serum creatinine with calculated creatinine clearance) 1, 2

Annually:

• Hepatitis C antibody testing (unless high-risk, then more frequent) 2

Important Caveats

• For patients with active hepatitis B, TDF/emtricitabine should never be discontinued abruptly without careful monitoring, as this can precipitate acute hepatitis flares or hepatic decompensation 2
• Same-day PrEP initiation is reasonable if rapid HIV test is negative and the patient is asymptomatic, without waiting for baseline labs, as long as these are drawn and results reviewed promptly 2
• The three-month HIV testing interval is based on the window period for HIV detection and the need to identify seroconversion early to prevent drug resistance 1, 4