PrEP Provider Toolkit

PrEP Initiation

Intake Laboratory Testing

The 2021 PrEP Guidelines published by the CDC include updated tables that organize the recommended laboratory tests for oral and intramuscular PrEP. As shown in Table 5. Careful considerations regarding PrEP Use and Table 7. Recommended Labs for Pre-exposure Prophylaxis Using F_TDF or F_TAF

While these tables present comprehensive information that highlight the subtleties of PrEP management, they can be challenging to interpret, especially for clinicians newly introduced to PrEP.

Below are modified tables for PrEP labs that work to simplify the guidelines. These suggestions are all drawn from related evidence-based studies. They aim to enhance patient care without sacrificing patient safety.

Note that HIV-RNA at initiation is recommended in select scenarios out of concern for delayed seroconversion or HIV acquisition during the ITRI as previously discussed. Also, labs recommended at discontinuation are represented in bold.

Detailed explanation of these lab recommendations are found in the Explanation of Suggesting Labs section.

Recommended Labs for PrEP Using F/TDF or F/TAF
Test Initiation Q3 Q6 As Indicated
HIV-Ab/Ag    
HIV-RNA

If ANY of the following:

  • Used PO PrEP in past 3mo
  • Used IM PrEP in past 12mo
  • Concern for HIV infection during ITRI1
   
  • Concern for HIV infection during ITRI
  • At discontinuation
Complete Metabolic Panel  
  • eCrCl concerns
  • ALT concerns
  • At discontinuation
STI Panel2  
  • For test-of-cure or monitoring
  • Each pregnancy
  • By patient request
  • At discontinuation
Pregnancy Test  
  • Concern for pregnancy & patient request
  • At discontinuation
Hepatitis A Ab Total      
Hepatitis B Panel3    
  • HBsAg w/ each pregnancy (26)
Hepatitis C Ab4    
  • More frequent for PWIDs (27)
  • Each pregnancy
  • Persistent ALT > 23IU/L (28)

Footnotes

  1. ITRI = Inter-test reactivity interval. The time between HIV-RNA positivity and HIV-Ag/Ab positivity
  2. Syphilis (reverse screening algorithm).
    Chlamydia and Gonorrhea at all applicable sites (genitourinary / oropharyngeal / rectal).
  3. Surface antigen (HBsAg) + surface antibody (HBsAb) + core antibody (HBcAb)
  4. If HCV-Ab is positive, obtain HCV-RNA.
Table 7. Recommended labs for PrEP Using F/TDF or F/TAF
Recommended Labs for PrEP Using Injectable Cabotegravir
Test Initiation At 1mo f/u Q2 Months As Indicated
HIV-RNA
  • Concern for HIV infection
  • At discontinuation
Complete Metabolic Panel    
  • ALT concerns
STI Panel1    
  • For test-of-cure or monitoring
  • Each pregnancy
  • By patient request
  • At discontinuation
Pregnancy Test    
  • Concern for pregnancy & patient request
  • At discontinuation
Hepatitis A Ab      
Hepatitis B Panel2    
  • HBsAg w/ each pregnancy
Hepatitis C Ab3    
  • More frequent screening for PWIDs
  • Each pregnancy
  • Persistent ALT > 23IU/L

Footnotes

  1. Syphilis (reverse screening algorithm).
    Chlamydia and Gonorrhea at all applicable sites (genitourinary / oropharyngeal / rectal).
  2. If HCV-Ab is positive, obtain HCV-RNA.
Table 8. Recommended Labs for PrEP Using Injectable Cabotegravir