Table 2. Laboratory Evaluation and Monitoring for Use of Preexposure Prophylaxis

What to Assess	How to Assess	When to Assess
HIV serostatus	Antibody (serum or point-of-care) or nucleic acid testing³⁷	No more than 7 days before starting PrEP and every 3 months thereafter⁶
HBV serostatus	HBsAb, HBsAg, HBcAb	Before starting PrEP,⁶ and can be considered thereafter, depending on behavioral risks or potential exposures
Renal function	Creatinine clearance	Before starting PrEP, at 3 months, and every 3–6 months thereafter, depending on baseline function⁶
Pregnancy	Qualitative pregnancy test	Before starting PrEP and every 3 months thereafter^6,34