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FeedbackSexually transmitted infections (STIs) constitute a major health burden in the United States, and the reported incidence is increasing annually. These diseases are frequently asymptomatic and are most often caused by viruses or bacteria.
Some of the most common viral STIs are caused by HIV and human papillomavirus (HPV). The most common bacterial STIs are chlamydia, gonorrhea, and syphilis. Protozoans may also cause STIs; the most common example of this is trichomoniasis (a potential cause of vaginitis). STIs can have severe health consequences and, if left untreated, can lead to complications that include pelvic inflammatory disease, infertility, cervical cancer, and chronic pelvic pain. Additionally, STIs such as syphilis and trichomoniasis are associated with an increased risk of HIV acquisition and transmission. Laboratory testing is important for the screening and diagnosis of STIs. Appropriate screening prevents the spread of disease, and accurate diagnosis enables appropriate treatment and patient management.
Quick Answers for Clinicians
Specimen type and collection vary based on disease and are important for accurate laboratory testing results. For information about optimal specimen types and collection instructions for sexually transmitted infection (STI) laboratory testing, refer to ARUP's STI Testing Using Nucleic Acid Amplification Tests–Sample Collection Instructions.
The CDC provides detailed information about sexually transmitted infections (STIs), including screening recommendations, treatment guidelines, data and statistics, and other disease-specific information.
Trichomoniasis (a potential cause of vaginitis), herpes simplex virus (HSV), hepatitis B virus (HBV), hepatitis C virus (HCV), and human papillomavirus (HPV) may also be sexually transmitted and are often included in a sexually transmitted infection (STI) screening or workup. More information about these conditions can be found in the associated ARUP Consult topics or on the CDC website.
Indications for Testing
Laboratory testing to screen asymptomatic individuals is appropriate for most individuals. The Screening section provides detailed screening recommendations based on population.
Laboratory testing for the diagnosis of an STI is appropriate for individuals experiencing:
- Urgency, frequency, or dysuria in the absence of a documented urinary tract infection (UTI)
- Vaginal or penile discharge
- Pelvic pain
- Prostatitis symptoms
- Genital lesions such as painful vesicles or nonpainful shallow ulcers
Laboratory Testing
Screening
Screening for STIs is important to control the spread of these diseases because many STIs may be asymptomatic. The recommendations for screening vary by disease and population. The tables that follow detail the screening recommendations for chlamydia and gonorrhea in women, pregnant individuals, men, men who have sex with men (MSM), and persons with HIV, and screening recommendations for trichomoniasis in women, men, and those with HIV. For transgender individuals, STI screening should be based on current anatomy and sexual practices.
For detailed information about screening for syphilis, HIV, herpes simplex virus (HSV), and trichomoniasis, visit the corresponding ARUP Consult topics.
Refer to ARUP's STI Testing Using Nucleic Acid Amplification Tests–Sample Collection Instructions to determine the optimal specimen types and for collection instructions.
| Population | Testing Recommended in These Patients/Circumstancesa |
|---|---|
|
Women |
Sexually active women <25 yrs and sexually active women ≥25 yrs who are at increased riskb; retest approximately 3 mos after treatment Consider pharyngeal and rectal screening based on reported sexual behavior |
|
Pregnant individuals |
All pregnant individuals <25 yrs and those ≥25 yrs who are at increased riskb; retest women <25 yrs or those at risk in third trimesterb |
|
Men |
No screening recommended for individuals at low risk,c but consider screening young men in high-prevalence clinical settings or in populations with high burden of infection |
|
MSM |
Annually at sites of contact Repeat testing every 3-6 mos in those at increased riskd |
| Transgender and gender-diverse persons | Adapt screening recommendations based on anatomy; consider rectal screening based on reported sexual behavior and exposure |
|
Persons with HIV |
All sexually active individuals at first HIV evaluation, then at least annually More frequent screening may be appropriate depending on risk behaviors and local epidemiology |
|
aUnless otherwise noted, all recommendations come from the CDC. bThe CDC defines persons at increased risk as those who have a new sexual partner, >1 sexual partner, a sexual partner with concurrent partners, or a sexual partner who has an STI. cThe USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening men for chlamydia and gonorrhea. dAll MSM, including those with HIV infection, if risk behaviors persist or if they or their sexual partners have multiple partners. |
|
| Population | Testing Recommended in These Patients/Circumstancesa |
|---|---|
|
Women |
Sexually active women <25 yrs and sexually active women ≥25 yrs who are at increased riskb,c; retest approximately 3 mos after treatment Consider pharyngeal and rectal screening based on reported sexual behavior |
|
Pregnant individuals |
All pregnant individuals <25 yrs and those ≥25 yrs who are at increased riskb |
|
Men |
No screening recommended for heterosexual men at low risk for infectiond |
|
MSM |
All sexually active MSM: annually at sites of contact Repeat testing every 3-6 mos in those at increased risk |
| Transgender and gender-diverse persons | Adapt screening recommendations based on anatomy; consider rectal screening based on reported sexual behavior and exposure |
|
Persons with HIV |
All sexually active individuals at first HIV evaluation, then at least annually More frequent screening may be appropriate depending on risk behaviors and local epidemiology |
|
aUnless otherwise noted, all recommendations come from the CDC. bThe CDC defines persons at increased risk as those who have a new sexual partner, >1 sexual partner, a sexual partner with concurrent partners, or a sexual partner who has an STI. cAdditional risk factors for gonorrhea include inconsistent condom use among persons who are not in mutually monogamous relationships, previous or coexisting STIs, and exchanging sex for money or drugs; clinicians should consider the communities they serve and may opt to consult local public health authorities for guidance to identify groups that are at increased risk. dThe USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening men for chlamydia and gonorrhea. eAll MSM, including those with HIV infection, if risk behaviors persist or if they or their sexual partners have multiple partners. |
|
| Population | Testing Recommended in These Patients/Circumstances |
|---|---|
| Women | Screening is not recommended for asymptomatic women but may be considered in women receiving care in high-prevalence settings or at high risk for STIsa |
| Men | No screening recommended |
| Persons with HIV | Routine screening for T. vaginalis recommended in asymptomatic persons with HIV infection |
| Sources: CDC, 2021 | |
Diagnosis
Specific testing recommendations for syphilis, HIV, HSV, and vaginitis caused by trichomoniasis can be found in the corresponding ARUP Consult topics. Accurate diagnosis is important to determine appropriate treatment and medical management. Nucleic acid amplification testing (NAAT) is recommended for diagnosis of most STIs, although in some cases, culture and serology may be useful.
Refer to ARUP's STI Testing Using Nucleic Acid Amplification Tests–Sample Collection Instructions for optimal specimen types and collection instructions for these laboratory tests.
ARUP Laboratory Tests
Preferred test for detecting Chlamydia trachomatis and Neisseria gonorrhoeae in a variety of specimens
Requires APTIMA collection kit
Does not include confirmation of positive results by an alternate nucleic acid target
Qualitative Transcription-Mediated Amplification
Use to detect C. trachomatis and N. gonorrhoeae in a variety of specimens
Positive results are confirmed using an alternate nucleic acid target
Qualitative Transcription-Mediated Amplification
Preferred test for detecting C. trachomatis, N. gonorrhoeae, and Trichomonas vaginalis in a variety of specimens
Qualitative Transcription-Mediated Amplification
Use to detect C. trachomatis and N. gonorrhoeae in ThinPrep specimens
Does not include confirmation of positive results by an alternate nucleic acid target
Transcription-Mediated Amplification
Use to detect T. vaginalis in various specimens
Qualitative Transcription-Mediated Amplification
Aids in the diagnosis of bacterial vaginosis, vulvovaginal candidiasis, and trichomoniasis
Qualitative Transcription-Mediated Amplification
Preferred test for detecting C. trachomatis in a variety of specimens
Does not include confirmation of positive results by an alternate nucleic acid target
Qualitative Transcription-Mediated Amplification
Preferred test for detecting N. gonorrhoeae in a variety of specimens
Does not include confirmation of positive results by an alternate nucleic acid target
Qualitative Transcription-mediated Amplification
Detects but does not differentiate C. trachomatis L1-L3 serovars
Qualitative Polymerase Chain Reaction
SurePath media is not preferred when testing for C. trachomatis and N. gonorrhoeae by transcription-mediated amplification (TMA)
Use of transport media other than APTIMA specimen collection kit may result in reduced sensitivity
The preferred test is Chlamydia trachomatis and Neisseria gonorrhoeae by Transcription-Mediated Amplification (TMA) (0060241)
Transcription-Mediated Amplification
Not recommended for routine detection of C. trachomatis
Use to detect C. trachomatis in medicolegal settings and to assess suspected treatment failure
May be considered for anatomic locations for which amplified testing has not been validated
Cell Culture/Immunofluorescence
Can detect N. gonorrhoeae in specimens not approved for NAAT
Preferred testing is combined Chlamydia trachomatis and Neisseria gonorrhoeae by Transcription-Mediated Amplification (TMA) (0060241)
Culture
Medical Experts
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References
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CDC - Sexually transmitted diseases
U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Sexually transmitted diseases (STDs). [Last reviewed: Jun 2021; Accessed: Aug 2021]
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CDC - Sexually Transmitted infections Treatment Guidelines - Screening Recommendations
U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Sexually transmitted infections treatment guidelines, 2021: screening recommendations and considerations referenced in treatment guidelines and original sources. [Last reviewed: Sep 2021; Accessed: Aug 2021]
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Wangu Z, Burstein GR. Adolescent sexuality: updates to the sexually transmitted infection guidelines. Pediatr Clin North Am. 2017;64(2):389-411.
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US Preventive Services Task Force, Davidson KW, Barry MJ, et al. Screening for chlamydia and gonorrhea: US Preventive Services Task Force recommendation statement. JAMA. 2021;326(10):949-956.
WHO - guidelines for management of symptomatic sexually transmitted infections
World Health Organization. Guidelines for the management of symptomatic sexually transmitted infections. 2021. [Accessed: Sep 2021]
Components: Lactobacillus (L. gasseri, L. crispatus, and L. jensenii), Gardnerella vaginalis, Atopobium vaginae, Trichomonas vaginalis, Candida glabrata, and other Candida species (C. albicans, C. parapsilosis, C. dubliniensis, and C. tropicalis)