STD Testing Guide: Common Infections, Test Types, Window Periods, and CDC Recommendations

Educational guide · Reviewed June 2026 · By the Laboratories.org editorial team

Most sexually transmitted infections produce no symptoms, which means the only way to know your status is to test. This guide covers the eight infections most commonly included in STD panels, what sample type each requires, how long to wait after exposure before testing (the window period), and which tests the CDC recommends based on your situation.

Common STIs to test for

Eight infections account for the vast majority of STI burden globally. Four are bacterial or parasitic and can be cured with medication. Four are viral — they cannot be cured but can be managed, and early diagnosis significantly improves health outcomes and reduces transmission to partners.

According to the WHO, more than 1 million curable STI infections are acquired every day worldwide, with the majority being asymptomatic. In 2020, 374 million new infections with one of the four curable STIs occurred globally. The CDC estimates approximately 1 in 5 people in the US had an STI on any given day in 2018, with most unaware of their infection.

Test types — blood vs. urine vs. swab

Different infections are detected through different sample types. A complete STD panel typically combines a urine sample and a blood draw. Swabs are used when there are active sores or when testing non-genital sites.

Urine tests

Urine tests detect chlamydia, gonorrhea, and trichomoniasis. The patient provides a "first-catch" urine sample — the first portion of the urine stream, which contains the highest concentration of organisms from the urethra. The laboratory uses a Nucleic Acid Amplification Test (NAAT), which detects bacterial or parasite DNA or RNA. NAAT on urine is highly sensitive and is the preferred method for chlamydia and gonorrhea diagnosis. Gonorrhea may also require swab testing of additional sites (throat, rectum) if there was potential exposure at those locations.

Blood tests

Blood tests detect HIV, syphilis, herpes (HSV-1 and HSV-2 IgG antibodies), hepatitis B, and hepatitis C. A small blood draw from a vein is required for most of these; some rapid tests use a finger-stick.

Swab tests

Swab tests detect herpes from active sores (via PCR or viral culture), and gonorrhea and chlamydia at non-genital sites (throat, rectum). HPV is detected via cervical Pap smear for women. For herpes, a swab from an active blister or ulcer is the most accurate test — PCR is preferred over viral culture. Blood tests (IgG) are used when no active sores are present.

Herpes testing — key nuances

Herpes testing requires careful attention to which test is ordered and when. With an active lesion, a swab for PCR is the most accurate approach. Without active sores, the type-specific IgG blood test is appropriate.

IgM tests are not recommended for herpes. They cannot distinguish HSV-1 from HSV-2 and are not reliable for STI screening. The CDC does not recommend routine herpes blood testing for asymptomatic people with low infection risk due to the risk of false positives and the potential psychological impact of a diagnosis without clinical context. After exposure, it can take up to 16 weeks or more for a blood test to reliably detect HSV infection.

Hepatitis B — triple panel

The CDC recommends a triple-panel blood test for comprehensive hepatitis B evaluation:

1. HBsAg (surface antigen): Positive = currently infected (acute or chronic).
2. Anti-HBs (surface antibody): Positive = immune (from vaccination or past resolved infection).
3. Total anti-HBc (core antibody): Positive = previous or ongoing exposure at some point in life.

Hepatitis C — two-step testing

Hepatitis C testing uses two sequential steps. First, an HCV antibody test screens for past or current exposure — this test becomes reactive approximately 8–11 weeks after infection. If the antibody test is reactive, an HCV RNA (NAT/NAAT) test is performed to detect active viral RNA and confirm current infection. An RNA test can be positive within 1–2 weeks of exposure and is the definitive test for distinguishing active infection from a previously cleared infection.

Window periods

The window period is the time between infection or exposure and when a test can reliably detect that infection. Testing during the window period may produce a false-negative result — you may genuinely be infected, but the test cannot yet detect it because your body has not yet produced enough antibodies, antigens, or viral RNA to reach the detection threshold.

If a test result is negative but was taken within the window period, a follow-up test after the window period has passed is needed to confirm a true negative. For HIV specifically: a negative 4th-generation Ag/Ab test at 45 days post-exposure is considered reliable by most US and UK guidelines; a negative result at 90 days is considered conclusive.

CDC screening recommendations

The CDC's 2021 STI Treatment Guidelines, updated through 2025, provide evidence-based recommendations for who should get tested and how often. These are population-level guidance documents — your healthcare provider may recommend different testing based on your individual situation.

Universal recommendations

Women

Pregnant women

All pregnant women should be screened at the first prenatal visit for: syphilis (all), HIV (all; repeat in 3rd trimester if high risk), Hepatitis B — HBsAg (all, at each pregnancy), Hepatitis C (all), and chlamydia and gonorrhea (all under 25; those 25 and older if at increased risk).

Gay, bisexual, and men who have sex with men (MSM)

Retesting after treatment: For chlamydia, the CDC recommends retesting at 3 months after treatment due to high reinfection rates. For gonorrhea, retest at 3 months. For syphilis, retest at 6 and 12 months after treatment.

Basic vs. comprehensive panels

Choosing between a basic and a comprehensive panel depends on your risk level, whether you are entering a new relationship, and whether you want maximum reassurance about your overall status. Neither panel type requires a doctor's appointment — both are available through direct-to-consumer lab testing services.

Basic panel (4–5 infections)

A basic panel targets the four most frequently diagnosed and transmitted STIs: chlamydia, gonorrhea, HIV (typically 4th-generation Ag/Ab), and syphilis. Some basic panels also include trichomoniasis. A basic panel is appropriate for routine annual screening, first-time screening, or lower-risk individuals.

Limitation: A basic panel does not include herpes or hepatitis B and C — infections that can be lifelong and are often completely asymptomatic for years.

Comprehensive panel (7–10 infections)

A comprehensive panel includes everything in the basic panel plus herpes simplex virus types 1 and 2 (HSV-1 IgG and HSV-2 IgG blood tests), hepatitis B (HBsAg triple panel), hepatitis C (HCV antibody), and trichomoniasis if not already included. Some comprehensive panels also include mycoplasma genitalium.

Note on herpes in comprehensive panels: Some providers include HSV IgG in comprehensive panels, but the CDC notes that routine herpes blood testing of asymptomatic people at low risk is not recommended. This is because false-positive HSV results occur and can cause significant psychological distress. Providers should discuss the implications of testing before ordering. Quest Diagnostics DTC STD packages typically include chlamydia, gonorrhea, trichomonas, hepatitis B, hepatitis C, syphilis, and HIV.

Asymptomatic infections

One of the most important facts about STIs is that most produce no noticeable symptoms at all. Relying on symptoms to decide whether to get tested means that most infections go undetected — enabling continued transmission to partners and allowing complications to develop silently.

Because symptoms are an unreliable indicator of infection, the CDC and WHO both emphasize routine, schedule-based screening rather than symptom-triggered testing. Regular testing identifies infections before complications develop, breaks chains of transmission, and allows early treatment — which is more effective and prevents long-term health consequences. The treatment for HIV, for example, can reduce viral load to undetectable levels, which is associated with effectively zero risk of transmitting the virus to a partner (U=U: Undetectable = Untransmittable).

How confidential testing works

Direct-to-consumer STD testing allows individuals to order and receive STD tests without a doctor's referral, using the same certified laboratory infrastructure that hospitals and clinics use. Results go directly to the patient and are not automatically shared with employers, insurers, or anyone else.

The process (in-person lab draw)

1. Order online: Browse available tests or panels on the provider's website (e.g., QuestHealth.com or Labcorp OnDemand). Pay out-of-pocket; insurance may or may not apply.
2. Locate a lab: The service directs you to a nearby patient service center. Quest has 2,000+ locations; Labcorp has 2,000+ locations nationwide.
3. Visit the lab: Walk in or schedule an appointment. Provide a urine sample and a blood draw, depending on the panel ordered. No doctor's appointment or referral required.
4. Results delivered securely: Results are typically available within 1–5 business days, delivered to a secure online patient portal. You receive an email notification when results are ready.
5. Follow-up care: If results are positive or need discussion, most DTC platforms offer the option to speak with an independent healthcare provider. Treatment may be prescribed or a referral provided.

At-home collection kit variant

Some services mail a collection kit to your home. You self-collect samples (urine, finger-prick blood, or vaginal swab) and mail the sample to a certified lab in a prepaid envelope. Results arrive online within 2–5 days. Kits are shipped in plain, discreet packaging.

Confidentiality

Results go directly to the patient's portal — not automatically shared with an employer, insurer, or physician (unless the user chooses to share them). Tests use the same CLIA-certified laboratories and FDA-cleared methodologies used by hospitals and clinics. Quest's DTC STD testing is available in 45 states. Some states require a physician order and do not permit direct consumer ordering.