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STD testing

An STD test is a medical test for the presence of any of a number of sexually transmitted infections (STIs). Most STD tests are blood tests, and are usually performed after symptoms are detected (disease), but may detect asymptomatic or presymptomatic infections. STD tests may test for a single infection, or consist of a number of individual tests for any of a wide range of STIs, including tests for syphilis, gonorrhea, chlamydia, hepatitis and HIV tests. No STD procedure tests for all infectious agents, so it is important to be aware what organisms a given test screens for.

Additional recommended knowledge

STD tests may be used for a number of reasons:

  • as a diagnostic test for the diagnosis of illness
  • as a check that prospective long-term sexual partners are free of disease before they engage in sex without safer sex precautions (for example, in fluid bonding, or to attempt to have a baby). Some states require STD testing of both prospective partners before marriage.
  • as a check prior to or during pregnancy, to prevent damage to the baby
  • as a check after birth, to check that the baby has not caught an STI from their mother
  • to prevent the use of infected donated blood or organs
  • as part of the process of contact tracing from a known infected individual
  • as part of mass epidemiological surveillance

Not all STIs appear right away. In some instances a disease can be carried with no outward symptoms, which leaves a greater risk of passing the disease on to others.

Available tests

Tests are available (at various costs) for nearly all STIs, though a few currently may only be found by testing specifically for the DNA of the infectious agent, such as HPV. Such recombinant DNA tests are prohibitively expensive and may have unacceptable rates of false negatives or false positives. Some STIs may be detected by more than one testing method, such as gonorrhea & chlamydia, which may be observed in either a urine sample or on a urethral swab. The table below lists some available tests, though selection may be limited by healthcare provider, area, or cost; choices may also be broader than known to the editors of this article. Only diseases regarded as having sexual contact as a primary means of transmission are tabled here; other infections, such as influenza, common cold, and even Ebola & Marburg may be transmitted by sexual contact (including oral sex). The symbols in the table mean the following:

X - There is a known, reliable discriminatory test of this kind.

* - Though a reliable test exists of this kind, it cannot always be performed, possibly for lack of a symptomatic ulcer (sore) or other factors.

O - A subjective test that may allow confusion with other illnesses.

? - It is suspected that a useful test of this kind exists for this organism, but not yet confirmed.

No symbol means that no known test of that kind exists for that illness/disease/organism.

Tests available

Blood Swab Urine Symptoms Other
Gonorrhea ("The clap") X * O
Chlamydia X * O
Syphilis  ? * X
Chancroid X O
Donovanosis X X
NGU  ?  ? O X
Jock itch X  ?
Yeast infection X  ?
Candida albicans ("Thrush") X  ?
Molluscum contagiosum X X
Hepatitis (usu. 'B') X O
KSHV  ?  ?  ?
Mononucleosis X O
HPV  ? O X
Pubic lice ("crabs") X
Scabies X
Trichomoniasis * O

Dependence fallacy

A common fallacy is the view of STD testing as a kind of safe sex practice which overrides the actual practice of safe sex. Tests by definition are only informative and not preventative, and while important in keeping oneself and others informed of a partner's STD status, they do not take the place of preventative safe sex practice -- caution in selecting partners and refraining from promiscuity. They are however essential in the early treatment of STD's, and most STD's are, by current medical science, inherently treatable once discovered.

See also

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "STD_testing". A list of authors is available in Wikipedia.
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