Table 2. Laboratory Evaluation and Monitoring for Use of Preexposure Prophylaxis
What to AssessHow to AssessWhen to Assess
HIV serostatusAntibody (serum or point-of-care) or nucleic acid testing37No more than 7 days before starting PrEP and every 3 months thereafter6
HBV serostatusHBsAb, HBsAg, HBcAbBefore starting PrEP,6 and can be considered thereafter, depending on behavioral risks or potential exposures
Renal functionCreatinine clearanceBefore starting PrEP, at 3 months, and every 3–6 months thereafter, depending on baseline function6
PregnancyQualitative pregnancy testBefore starting PrEP and every 3 months thereafter6,34
  • HBV, hepatitis B virus; PrEP, preexposure prophylaxis.