Before starting PrEP (pre-exposure prophylaxis), review the health considerations and recommended tests below. These steps can help you prepare for a medical assessment and determine what testing you may need.

If you are unsure whether PrEP is right for you, consult a healthcare professional before starting treatment. The tests you need will depend on your medical history, potential HIV exposure, and the PrEP regimen being considered.

PrEP is intended to prevent HIV infection in people who do not have HIV. It is not a treatment for an existing HIV infection. Starting PrEP without identifying an existing infection may delay diagnosis and increase the risk of developing drug resistance.

A negative result from a home HIV self-test does not always rule out a recent infection. Depending on your exposure history, symptoms, and previous use of PrEP or PEP, your healthcare provider may recommend additional testing before prescribing PrEP. You may choose one of the following testing options based on your circumstances.

Option 1: HIV-1/2 Antigen/Antibody (Ag/Ab) Test

What it does: A laboratory-based fourth-generation test detects both HIV antibodies and the p24 antigen. It is commonly used to assess HIV status before starting PrEP.

Option 2: HIV-1 RNA Test (NAT/PCR)

What it does: Detects HIV genetic material in the blood. Your healthcare provider may recommend this test if you have had a recent potential exposure, have symptoms suggestive of acute HIV infection, or have inconclusive test results.

Option 3: In-Home Rapid HIV Self-Test

What it does: Allows you to screen for HIV at home. The type of sample and the test’s ability to detect infection depend on the specific product. A negative self-test alone cannot reliably rule out recent HIV infection or replace the clinical assessment required before starting PrEP.

Hepatitis B virus (HBV) can cause liver disease. Some oral PrEP medications, including TDF/FTC and TAF/FTC, are also active against HBV.

Having hepatitis B does not automatically mean you cannot take PrEP. However, knowing your HBV status before starting oral PrEP is important because stopping these medications in someone with chronic hepatitis B can cause the virus to reactivate and liver inflammation to worsen.

Hepatitis B Triple Panel

What it does: This blood test measures three markers. HBsAg (Hepatitis B Surface Antigen) helps identify a current hepatitis B infection. Anti-HBs (Hepatitis B Surface Antibody) helps determine whether you have immunity to hepatitis B, either from vaccination or recovery from a previous infection. Total Anti-HBc (Total Hepatitis B Core Antibody) indicates whether you have ever been exposed to the hepatitis B virus.

Some oral PrEP medications, particularly TDF/FTC, can affect kidney function. Although significant kidney problems are uncommon, assessing kidney function helps determine whether a particular PrEP regimen is appropriate for you.

If you have a history of kidney disease, diabetes, high blood pressure, or abnormal kidney test results, your healthcare provider may recommend additional testing or closer monitoring.

Serum Creatinine and Creatinine Clearance (CrCl) Assessment

What it does: A blood test measures serum creatinine, a waste product normally filtered out by the kidneys. Your healthcare provider uses this result and other relevant information to calculate your estimated creatinine clearance (CrCl), which helps assess how well your kidneys are filtering waste.

Kidney function requirements vary by medication. Under US CDC guidance, TDF/FTC generally requires an estimated CrCl above 60 mL/min, while TAF/FTC requires an estimated CrCl of at least 30 mL/min.

The CDC recommends assessing kidney function before starting oral TDF/FTC or TAF/FTC. Some WHO-supported service models allow routine baseline kidney testing to be omitted in selected people at low risk of kidney problems, such as those under 30 with no relevant risk factors. Whether testing is needed depends on the applicable clinical guidelines and your individual circumstances.

Sexually transmitted infections (STIs), including syphilis, gonorrhea, and chlamydia, can occur without noticeable symptoms. Identifying and treating these infections early can help prevent complications and protect your health.

Having an STI does not usually prevent you from starting PrEP. An STI diagnosis may, however, indicate a need for additional HIV prevention support. Your healthcare provider can arrange appropriate treatment while assessing whether PrEP is suitable for you.

Syphilis Serology

What it does: A blood test used to screen for syphilis. Depending on the test method and results, additional testing may be needed to confirm an infection.

Gonorrhea and Chlamydia NAAT

What it does: A nucleic acid amplification test (NAAT) detects the genetic material of the bacteria that cause gonorrhea and chlamydia. Depending on your sexual exposure history, testing may involve a urine sample or swabs from relevant anatomical sites, such as the throat or rectum.

Are STI tests required before starting PrEP?

STI screening is an important part of comprehensive PrEP care. The tests you need and how often you should be screened depend on your symptoms, sexual history, sites of potential exposure, and applicable clinical guidelines. If you have no symptoms and believe your risk of STI exposure is low, discuss your circumstances with your healthcare provider to determine which tests are appropriate. Keep in mind that many STIs cause no symptoms, so the absence of symptoms does not necessarily mean testing is unnecessary.

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* Important Information

This page is intended for general educational purposes only. It does not replace professional medical advice, diagnosis, or treatment.

Before prescribing PrEP, a healthcare professional should review your HIV status, medical history, current medications, and relevant test results. Not everyone needs every test listed here, and the appropriate assessment depends on your individual circumstances and the PrEP regimen being considered.