PrEP Provider Toolkit: Explanation of suggested labs

PrEP Provider Toolkit

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Explanation of suggested labs

Complete Metabolic Panel

A CMP is helpful in determining the estimated creatinine clearance (eCrCl).

F/TDF (Truvada) eCrCl ≥ 60ml/min
F/TAF (Descovy): eCrCl ≥ 30ml/min

Although current guidelines recommend different testing intervals based on age and eCrCl at initiation, these details may be cumbersome to remember. We recommend a CMP every 6 months for the sake of simplicity.
A CMP also helps determine if there is any existing or developing transaminitis which can be reflective of a multitude of related clinical scenarios e.g. hepatitis A/B/C infection, alcoholic liver disease, NAFLD, or hepatotoxicity from cabotegravir (Apretude)
For this reason, even though a full CMP is not officially recommended for any forms of PrEP, we recommend it as it is commonly ordered, relatively inexpensive, and a highly useful lab for the patient populations in consideration

STI Panel

More frequent testing may be performed if the patient engages in unprotected sex, sex with new partners, has concerning symptoms, or is directly requesting testing.
Remember that most STI infections are asymptomatic so testing should not be overlooked based on the absence of symptoms.
We suggest routine STI testing regardless of the patient’s sex or gender. This is to reduce confusion and respond to the overall worsening rates of STIs across the country.
Syphilis: testing algorithms may vary based on your institution. There are more advantages with the reverse sequence screening algorithm where treponemal immunoassays (EIA/CIA) are utilized first before the commonly used non-treponemal test (RPR/VDRL). Click here for a review on testing and managing the results of syphilis.
Chlamydia & Gonorrhea: test all applicable sites based on sexual practices (i.e. urogenital, pharynx, rectum). Swabs are either Aptima Combo 2 Assay or the Xpert CT/NG. Review chlamydia. Review gonorrhea.

Urogenital - first-catch urine samples are typically used. Contrary to the collecting procedures for a urinary tract infection (UTI), patients should be instructed not to clean their urethral opening with an alcohol swab and should urinate directly and immediately into the sample cup, not midstream.
Self-collected vaginal swabs is another option that can be offered to individuals AFAB. They perform better than clinician-collected samples and have the advantages of preserving patient comfort and circumventing the inability to provide a urine sample. ₍₃₆₎

Knox, Tabrizi, S. N., Miller, P., Petoumenos, K., Law, M., Chen, S., & Garland, S. M. (2002). Evaluation of self-collected samples in contrast to practitioner-collected samples for detection of chlamydia trachomatis, neisseria gonorrhoeae, and trichomonas vaginalis by polymerase chain reaction among women living in remote areas. Sexually Transmitted Diseases, 29(11), 647–654.
https://doi.org/10.1097/00007435-200211000-00006

Lunny, Taylor, D., Hoang, L., Wong, T., Gilbert, M., Lester, R., Krajden, M., Ogilvie, G., & Greub, G. (2015). Self-collected versus clinician-collected sampling for chlamydia and gonorrhea screening: a systemic review and meta-analysis. PloS One, 10(7), e0132776–e0132776
https://doi.org/10.1371/journal.pone.0132776

Pharynx - recommended if a patient performs oral sex.
Rectum - recommended if the patient engages in receptive anal intercourse (RAI). It is also possible for patients AFAB to get rectal infections from vaginal secretions without actually engaging in anal sex. Shared decisions should be made and samples may be self-collected. ₍₃₇₎

Gratrix, Singh, A. E., Bergman, J., Egan, C., Plitt, S. S., McGinnis, J., Bell, C. A., Drews, S. J., & Read, R. (2015). Evidence for increased chlamydia case finding after the introduction of rectal screening among women attending 2 Canadian sexually transmitted infection clinics. Clinical Infectious Diseases, 60(3), 398–404.
https://doi.org/10.1093/cid/ciu831

Pregnancy Test

Recommended for all sexually active patients of child-bearing potential. More frequent testing may be indicated if the patient is not on a reliable form of birth control and/or has related concerns. Conversely, frequency of testing may be reduced if a patient is on a reliable form of birth control or is not reporting any sexual activity during the interim period.

Hepatitis A Virus Total Ab

There are overlapping patient populations at higher risk for contracting both HIV and HAV. This includes MSM/TGWSM, PWIDs, individuals who are incarcerated, and individuals experiencing homelessness. For this reason we recommend obtaining a total HAV Antibody (HAV IgG+IgM) and providing vaccination if appropriate. Post-vaccination serology is not routinely recommended.

Hepatitis B Virus Panel (surface Ag, surface Ab, core Ab)

There are overlapping patient populations at higher risk for contracting both HIV and HBV such as MSM/TGWSM and PWIDs. Screening for HBV is also recommended for those born in countries with prevalence >2%, pregnant patients, and patients with abnormal ALT levels. Full details of general HBV screening. This is the rationale we used to recommend HBV screening as PrEP intake labs.
In accordance with guidelines published by the United States Preventive Services Task Force (USPSTF) and the American College of Physicians (ACP), we recommend Hepatitis B surface antigen (HBsAg), total Hepatitis B surface antibody (HBsAb), and total Hepatitis B core antibody (HBcAb). Vaccination is recommended if appropriate. Post-vaccination serology is generally not recommended (only select populations). ₍₃₈₎

Schillie, Vellozzi, C., Reingold, A., Harris, A., Haber, P., Ward, J. W., & Nelson, N. P. (2018). Prevention of hepatitis B virus infection in the United States: recommendations of the advisory committee on immunization practices. MMWR. Recommendations and Reports, 67(1), 1–31.
https://doi.org/10.15585/mmwr.rr6701a1

Hepatitis C Virus Ab

Both the CDC and the USPSTF recently updated their recommendations for HCV screening to include all adults 18 years of age or older.For review of screening guidelines, click here. Similar to the previously mentioned viral hepatitis infections, there are many overlapping risk factors between contracting HCV and HIV: MSM, transgender women, and PWIDs. ₍₃₉₎

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
HCV antibody testing (HCV Ab) is recommended at intake. Preferably, a HCV Ab test that reflexively tests for HCV RNA would be most helpful in determining next-step strategies. Review of HCV test interpretation.
More frequent testing may be recommended particularly among PWIDs who share injection equipment.

Lipid Panel

We decided to forego the inclusion of the lipid panel when a patient is receiving F/TAF (Descovy). Although it is well-established that F/TAF (Descovy) may cause worsening cholesterol-related parameters, existing 96-week and 144-week data from the DISCOVER trial found very minimal changes in such lab values. No significant adverse events or discontinuations resulted from these lipid changes. To further help patients decide, it may be worth mentioning that F/TDF (Truvada) is actually related to slightly improved lipid profiles. It is also weight neutral whereas F/TAF (Descovy) can lead to roughly 1.5 pounds of weight gain a year.

These disease-oriented data points do not equate to patient-oriented outcomes.

To expand on this, even though F/TDF (Truvada) may cause declines in bone mineral density (BMD), no actual increases in fractures have actually been connected to its use. ₍₄₀₎ Likewise, the slightly worsening lipid profiles of those on F/TAF (Descovy) have not been associated with higher rates of conditions such as pancreatitis or heart attacks. ₍₄₁₎ If use of F/TDF (Truvada) does not necessitate the routine use of DEXA scans or more frequent renal function monitoring, neither should the use of F/TAF (Descovy) necessitate the need of lipid panels.

Ogbuagu, Ruane, P. J., Podzamczer, D., Salazar, L. C., Asmuth, D. M., Wohl, D., Gilson, R., Shao, Y., Cox, S., Kintu, A., Carter, C., Baeten, J. M., Brainard, D. M., Whitlock, G., Brunetta, J. M., Spinner, C. D., Antinori, A., Apea, V., Avery, A., … Brar, I. (2021). Long-term safety and efficacy of emtricitabine and tenofovir alafenamide vs emtricitabine and tenofovir disoproxil fumarate for HIV-1 pre-exposure prophylaxis: week 96 results from a randomised, double-blind, placebo-controlled, phase 3 trial. The Lancet HIV, 8(7), e397–e407.
https://doi.org/10.1016/S2352-3018(21)00071-0

Sivay, Li, M., Piwowar-Manning, E., Zhang, Y., Hudelson, S. E., Marzinke, M. A., Amico, R. K., Redd, A., Hendrix, C. W., Anderson, P. L., Bokoch, K., Gail-Bekker, L., van Griensven, F., Mannheimer, S., Hughes, J. P., Grant, R., & Eshleman, S. H. (2017). Characterization of HIV seroconverters in a TDF/FTC PrEP study: HPTN 067/ADAPT. JAIDS-Journal of Acquired Immune Deficiency Syndromes, 75(3), 271–279.
https://doi.org/10.1097/QAI.0000000000001374

It is not our intention to carelessly overlook these potentially harmful differences. Certainly, if a patient has medical conditions or concerns related to their weight and/or cholesterol, counseling and monitoring should be performed.

In our opinion, this is more appropriate in the setting of a general health assessment rather than a focused visit for PrEP care. Again, the intention of these modifications is to structure a simplified and consistent approach that provides more patient-centered, evidence-based, and comprehensive care.