Baseline Laboratory Testing for Starting PrEP

Essential Baseline Tests

The American Medical Association recommends a combined HIV antibody and antigen test (4th generation) as the primary screening test for individuals starting PrEP 1, 2, 3
If a combined HIV antibody and antigen test is performed within 7 days of the visit and is negative, with no symptoms of acute HIV, PrEP can be initiated on the same day 1, 2, 4
For individuals with a clinical suspicion of acute HIV infection, HIV RNA testing should be added, and PrEP should be withheld until the results are available 1, 2, 3
Serum creatinine with calculated creatinine clearance (CrCl) should be obtained at baseline, but PrEP initiation should not be delayed while waiting for creatinine results 5, 6, 7, 8
The Centers for Disease Control and Prevention recommend hepatitis B surface antigen testing, STI screening, and hepatitis C antibody testing at baseline, but PrEP should not be delayed while waiting for these test results 5, 6
A pregnancy test should be performed at baseline for applicable individuals, but PrEP initiation should not be delayed while waiting for the results 7, 5

The primary goal of baseline testing is to prevent PrEP administration in individuals with undiagnosed HIV infection, and PrEP should not be delayed waiting for any test results except HIV testing 1, 2, 3, 7, 5, 8
If symptoms suggestive of acute HIV infection are present, PrEP should be withheld pending HIV RNA results 1, 2, 3

The World Health Organization recommends considering tenofovir alafenamide formulation for individuals with pre-existing bone or renal concerns 1
PrEP initiated during undiagnosed acute HIV infection can lead to drug resistance, and HIV RNA testing is particularly important if recent ARV exposure or symptoms are present 9, 10
If high-risk exposure occurred within 72 hours, a 3-drug PEP regimen should be started first, then transitioned to 2-drug PrEP after 28 days, with combined antibody/antigen test and HIV RNA performed at PEP conclusion 1, 2, 3