Testing for Sexually Transmitted Diseases (STDs)

Sexually transmitted diseases can be spread through unprotected sex, even one time, with an infected partner. Therefore, STD testing is an important part of maintaining good health for anyone who is sexually active.

Contact your health care provider or an STD clinic if you develop STD symptoms, such as abnormal discharge from the vagina, penis, urethra, or anus; or a rash, lesion (e.g., sore, wart), or inflammation in the genital area. People who engage in high risk sexual behavior (e.g., unprotected sex with multiple partners) should be tested for STDs at least once every year, even if they do not experience symptoms.

There are several different kinds of STD tests and the type of test performed depends on which sexually transmitted infection (STI) is suspected. Some STDs, including genital warts, scabies, and crabs (pubic lice), may be diagnosed based on a physical examination, a history of symptoms, and/or possible or confirmed STI exposure.

During the physical exam, a health care provider checks the anogenital area (i.e., the genitals and anus) for signs of an STD. In women, a pelvic exam is performed to detect possible STD complications that affect the internal reproductive organs (e.g., cervix, uterus, ovaries, fallopian tubes), such as pelvic inflammatory disease (PID).

STD testing often involves a microscopic examination of cell, tissue, or discharge samples and other laboratory tests to detect pathogens that cause STDs (e.g., bacterium, virus). Samples may be taken from the anogenital area (e.g., vagina, cervix, penis, urethra, anus) and/or from the inside of the mouth. In a culture, the sample is grown in a laboratory and then examined for the presence of pathogens. Other tests used to diagnose STDs include blood tests (e.g., immunoglobulin G [IgG], enzyme immunoassay [EIA], rapid plasma reagin [RPR]) and urine tests (e.g., ligase chain reaction [LCR], urine culture).

STD test results usually are available in days to weeks. In some cases, sexually transmitted diseases cannot be detected immediately after exposure and testing must be repeated. When a sexually transmitted infection is strongly suspected (e.g., when symptoms are present or exposure is confirmed), antibiotic treatment often is started before the disease is confirmed through testing.

Home test kits for some STDs are also available. In these tests, a sample (e.g., genital, rectal, oral swab; urine sample; blood sample) is taken at home and then mailed or brought to a laboratory for analysis. Positive home test results usually must be confirmed by your health care provider or at an STD clinic.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 12 Nov 2009

Last Modified: 05 Oct 2015