PrEP Provider Toolkit: Intake Laboratory Testing

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
Recommended Labs for PrEP Using Injectable Cabotegravir

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₎ Abara, Qaseem, A., Schillie, S., McMahon, B. J., & Harris, A. M. (2017). Hepatitis B vaccination, screening, and linkage to care: best practice advice from the American College of Physicians and the Centers for Disease Control and Prevention. Annals of Internal Medicine, 167(11), 794–804. https://doi.org/10.7326/M17-1106
Hepatitis C Ab⁴	●			More frequent for PWIDs ₍₂₇₎ Schillie, Wester, C., Osborne, M., Wesolowski, L., & Ryerson, A. B. (2020). CDC recommendations for hepatitis C screening among adults - United States, 2020. MMWR. Recommendations and Reports, 69(2), 1–17. https://doi.org/10.15585/mmwr.rr6902a1 Each pregnancy Persistent ALT > 23IU/L ₍₂₈₎ Akkaya, Kiyici, M., Yilmaz, Y., Ulukaya, E., & Yerci, O. (2007). Clinical significance of activity of ALT enzyme in patients with hepatitis C virus. World Journal of Gastroenterology: WJG, 13(41), 5481–5485. https://doi.org/10.3748/wjg.v13.i41.5481
Footnotes ITRI = Inter-test reactivity interval. The time between HIV-RNA positivity and HIV-Ag/Ab positivity Syphilis (reverse screening algorithm). Chlamydia and Gonorrhea at all applicable sites (genitourinary / oropharyngeal / rectal). Surface antigen (HBsAg) + surface antibody (HBsAb) + core antibody (HBcAb) 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 Syphilis (reverse screening algorithm). Chlamydia and Gonorrhea at all applicable sites (genitourinary / oropharyngeal / rectal). If HCV-Ab is positive, obtain HCV-RNA.
Table 8. Recommended Labs for PrEP Using Injectable Cabotegravir