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INTRODUCTION — Sexually transmitted infections (STIs) are a major public health problem in both resource-rich and limited settings. STIs are frequently asymptomatic and can lead to various complications. The immediate goal of screening for STIs is to identify and treat infected persons before they develop complications and to identify, test, and treat their sex partners to prevent transmission and reinfections.
In this topic, we discuss screening for STIs among asymptomatic individuals. In its 2015 guidelines on the treatment of sexually transmitted infections, the United States Centers for Disease Control and Prevention (CDC) also made recommendations on screening . The US Preventive Services Task Force (USPSTF) has also released guidelines on screening for various STIs [2-4]. The Infectious Diseases Society of America's HIV Medical Association has published STI screening recommendations for HIV-infected persons . The recommendations in this topic are largely consistent with these guidelines. Other subspecialty group guidelines and national guidelines may be more pertinent in certain settings [6-9].
The approaches to patients with specific genitourinary symptoms and signs are discussed elsewhere. (See "Approach to women with symptoms of vaginitis" and "Pelvic inflammatory disease: Clinical manifestations and diagnosis" and "Approach to the patient with genital ulcers" and "Acute uncomplicated cystitis and pyelonephritis in women".)
Information on the clinical presentation, diagnosis, and treatment of specific STIs are reviewed in detail separately (see related topics). Sexually transmitted infections and HIV infection in adolescents are also discussed separately. (See "Sexually transmitted infections: Overview of issues specific to adolescents" and "The adolescent with HIV infection".)
The prevention of STIs is also discussed elsewhere. (See "Prevention of sexually transmitted infections".)
RATIONALE — Complications of untreated sexually transmitted infections (STIs) include upper genital tract infections, infertility, chronic pelvic pain, cervical cancer, and chronic infection with hepatitis viruses and HIV. The approach to STI diagnosis and management is based upon disease or symptom-specific syndromes, including vaginal discharge, urethral discharge, ulcerative genital disease, nonulcerative genital disease, and pelvic pain. However, many patients have asymptomatic disease, which increases the risk of complications and sustained transmission in the community. Thus, screening is an important approach to identify and treat infected individuals, who would otherwise go undetected. Routine screening for all potential STIs in all patients is cost-prohibitive ; targeted screening of asymptomatic patients in specified risk groups is more feasible.
There is little direct evidence supporting the efficacy of screening programs. Screening for chlamydia has been the most extensively studied. The drawbacks to screening pertain largely to expense of the tests, the infrastructure required to administer them, and the psychological and relationship repercussions of false positive tests, which do occur, particularly among low prevalence populations.
Chlamydia and gonorrhea — Infections with Chlamydia trachomatis and Neisseria gonorrhoeae are very common. In the United States, they are the two most commonly reported communicable diseases. In females, the primary benefit of screening and treatment is to reduce their personal risk of reproductive sequelae. In males, who have a lower risk of long-term sequelae or more frequently have symptomatic disease, the main rationale for screening and treatment would be to reduce the likelihood of reinfection of sex partners and reduce overall transmission of these infections.
Females — Among women, most chlamydial and gonococcal infections are asymptomatic or minimally symptomatic and if left untreated, can lead to serious complications, including pelvic inflammatory disease (PID), infertility, complications of pregnancy, and chronic pelvic pain [2,11]. (See "Clinical manifestations and diagnosis of Chlamydia trachomatis infections", section on 'Clinical syndromes in women' and "Clinical manifestations and diagnosis of Neisseria gonorrhoeae infection in adults and adolescents", section on 'Urogenital infection in women'.)
Because the incidence of these infections are highest among adolescents and young adults, screening efforts have focused on this age group. Some proponents have argued that school-based health centers should implement systematic screening programs in adolescents to target these high-risk populations . For older women, decisions on screening are based on the presence of personal behavioral risk factors. (See 'Risk factors' below.)
Several trials have suggested that screening young women for chlamydia reduces the rate of subsequent PID, although some limitations reduce certainty about the findings [13-16]. As an example, in a trial of female college students in London, all participants provided vaginal swabs at study entry and were then randomly assigned to screening (in which the samples were tested for chlamydia and those with positive tests were treated) or control (in which the samples were stored and analyzed at the end of the study) [14,17]. Among those with chlamydia at baseline, 1 of 63 in the intervention group versus 7 of 74 in the control group developed PID (RR 0.17, 95% CI 0.03- 1.01). However, 30 of the 38 cases of PID observed in the study occurred in participants with negative baseline chlamydia, and 10 of those cases were documented to be associated with chlamydia. These findings indicate the importance of ongoing chlamydial transmission and the need for repeated screening over time in at-risk individuals.
Data on the effect of screening on prevalence of chlamydia are less clear. In one study of women and men ages 16 to 29 years in the Netherlands who were offered yearly home-based chlamydia screening tests for three years, participation was low (10 to 16 percent), and there was no evidence of reduced chlamydia rates after three rounds of screening . Effects on population prevalences could not be reliably estimated because of low uptake.
Although rectal chlamydial infections in women have been increasingly recognized, the adverse consequences of undetected, untreated infection at this site are unknown, and thus these are not generally screened for. (See "Epidemiology of Chlamydia trachomatis infections", section on 'Extragenital infections'.)
Males — The major rationale for chlamydia and gonorrhea screening among men is to reduce infection or reinfection of existing partners and transmission to new partners. For men who have sex with only women, it is unclear if this would be of additive benefit over screening women and treating them and their sex partners. Screening is thus more relevant among men who have sex with men (MSM), among whom there is a high burden of STIs, which would be less likely impacted by screening efforts among women.
MSM are at high risk of STIs, in part, because of individual behavioral risk, but also because of other factors, such as a higher prevalence of these infections within MSM sexual networks. In the United States, the median prevalence of chlamydia and gonorrhea among MSM seen at STI clinics throughout the country is approximately 16 and 19 percent, respectively . Prevalence is even higher among HIV-infected MSM. Although there are few data to show that these screening tests improve outcomes, it is reasonable to perform screening on at least an annual basis given the high prevalence rates of these STIs in MSM and the higher prevalence of antimicrobial resistance among gonococcal isolates in this population. (See "Treatment of uncomplicated gonococcal infections", section on 'Antibiotic resistance'.)
Evaluation for infection at non-genital sites is also important in this population. Several studies have reported that a significant proportion of gonorrhea and chlamydia cases would be missed if genital-only screening were performed [20-23]. For example, over a seven-year period, 7333 MSM attending a STI clinic in the United States underwent culture and/or NAAT sampling of multiple sites . The study demonstrated that one-third of the total number of N. gonorrhoeae cases would have been missed if only urethral or urine samples were tested. Similar findings have been reported in HIV-infected MSM . It has also been suggested that the acquisition of drug resistance mainly takes place at extragenital sites, such as the throat, where horizontal gene transfer of resistance determinants is more likely to occur than in the urethra .
For men who have sex with only women, there is little rationale for routine screening for chlamydia and gonorrhea. Evidence to support routine screening of chlamydia in men is lacking. Although screening and treating asymptomatic men for STI can reduce the burden of infection and thus transmission, it is unclear if this would be of additive benefit over screening women and treating them and their sex partners. Nevertheless, it is reasonable to screen heterosexual men for chlamydia in high prevalence settings (eg, at STI or adolescent clinics and correctional facilities) if resources allow and screening programs for men would not negatively impact those for women .
Among asymptomatic heterosexual men, gonorrhea prevalence is low (0 to 1.5 percent), in contrast to rates as high as 28 percent among symptomatic men in some settings . Focusing on treating symptomatic men would thus likely address a significant proportion of the gonococcal burden among heterosexual men, and screening asymptomatic men may not add substantial value.
Trichomonas — Trichomonas vaginalis infection is often asymptomatic, has been associated with adverse pregnancy outcomes, and, among HIV-infected women, an increased risk of PID. Some studies have suggested that vaginal trichomoniasis is also a risk factor for HIV acquisition and transmission [27,28]. The prevalence of trichomoniasis appears to increase with increasing age and is up to twice as high in HIV-infected women. There are currently no recommendations to routinely screen for trichomoniasis in HIV-uninfected women because the value of screening in reducing complications in non-HIV-infected reproductive-aged women is not well established. (See "Trichomoniasis".)
Syphilis — Syphilis can lead to serious long-term sequelae, including cardiac and neurologic manifestations, which are prevented by treatment in the early stages of disease, which can be minimally symptomatic or easily left undiagnosed. Screening and treatment can also reduce transmission of infection. Additionally, syphilis is associated with an increased risk for HIV transmission and acquisition [29,30].
Although syphilis is not as common as chlamydia or gonorrhea, the prevalence can be high among certain risk groups. As an example, in the United States, the majority of all primary and secondary syphilis cases occur among MSM, many of whom are HIV-infected .
In the United States, the USPSTF recommends routine screening of asymptomatic persons who are at increased risk of syphilis, in particular MSM and HIV-infected individuals . (See "Syphilis: Screening and diagnostic testing", section on 'Asymptomatic patients'.)
HIV and hepatitis viruses — Untreated HIV infection, chronic hepatitis B virus (HBV) infection, and chronic hepatitis C virus (HCV) infection can result in substantial excess morbidity and mortality for the infected individual and contribute to further transmission of these infections. These infections can be transmitted sexually as well as through other modes of transmission, and screening is recommended for broader populations than just those at risk of sexual acquisition. Rationale for screening for these infections is discussed elsewhere:
Sexual transmission of HCV is not particularly efficient, and the risk is very low among monogamous sexual partners. However, the risk is higher in those with multiple sexual partners, and sexual transmission among MSM has been increasingly reported, particularly among HIV-infected MSM [31-37]. (See "Epidemiology and transmission of hepatitis C virus infection", section on 'Sexual or household contact' and "Epidemiology, natural history, and diagnosis of hepatitis C in the HIV-infected patient", section on 'Men who have sex with men'.)
Human papillomavirus — Persistent viral infection with specific high-risk genotypes of human papillomavirus (HPV) causes virtually all cancers of the cervix and is associated with oropharyngeal and anal cancer.
Screening currently focuses on detection of oncogenic HPV infection and/or the cytologic abnormalities that can be caused by persistent HPV infection.
The rationale for cervical cancer screening among females is discussed in detail elsewhere. In the United States, guidelines issued by various professional organizations strongly recommend screening for cervical cancer, although there are minor differences in the recommended screening parameters. Cervical cancer screening policies in other countries also differ by starting age, stopping age, and frequency. (See "Screening for cervical cancer" and "Screening for cervical cancer in HIV-infected women and adolescents".)
The rationale of screening for AIN in individuals at increased risk for anal cancer is discussed separately. (See "Anal squamous intraepithelial lesions: Diagnosis, screening, prevention, and treatment", section on 'Screening for anal SIL'.)
There are no screening tests for HPV-associated oropharyngeal cancers.
HPV vaccination can prevent HPV infection and its sequelae. Vaccination status does not change recommendations for screening. This is discussed in detail elsewhere. (See "Recommendations for the use of human papillomavirus vaccines".)
Mycoplasma genitalium — Routine screening for M. genitalium is not recommended . It is a recognized cause of nongonococcal urethritis in men and has been associated with cervicitis and PID in women. However, testing for M. genitalium is not widely available, and the benefits of screening and treatment in asymptomatic persons are unclear.
Herpes simplex virus — Routine screening for genital herpes simplex virus (HSV) infections is not recommended . However, performing type-specific serological testing for HSV can be useful on an individual basis to counsel couples on their risk for HSV transmission, particularly during pregnancy. (See "Genital herpes simplex virus infection and pregnancy", section on 'Screening pregnant women with no HSV history' and "Prevention of genital herpes virus infections", section on 'Determining partner susceptibility to infection'.)
Genital HSV is common and can be subclinical. The majority of infections are transmitted from individuals unaware of their infection or during asymptomatic periods between outbreaks. However, treatment is generally reserved for those with symptomatic disease, and there is no evidence that more widespread treatment will reduce the burden of genital HSV.
In the United States, the USPSTF recommends against routine screening for HSV in asymptomatic individuals (including pregnant women) . The CDC also indicates that routine serologic screening in the general population is not indicated but can be considered for those presenting for an STI evaluation, HIV-infected individuals, and MSM at risk for HIV infection .
Risk factors — Risk factors for sexually transmitted infections (STIs) include both sexual behavior that increases the risk of exposure to STIs and risk groups that have a high prevalence of STIs [38-46].
Behavioral risk factors include:
●New sex partner in past 60 days
●Multiple sex partners or sex partner with multiple concurrent sex partners
●No or inconsistent condom use outside a mutually monogamous sexual partnership
●Trading sex for money or drugs
●Sexual contact (oral, anal, penile, or vaginal) with sex workers
●Meeting anonymous partners on the internet
Risk groups are demographic groups identified as having a high prevalence of STIs.
●Young age (15 to 24 years old)
●Men who have sex with men (MSM)
●History of a prior STI
●Lower socioeconomic status, or high school education or less
●Admission to correctional facility or juvenile detention center
●Illicit drug use
The risk of STIs is particularly high among sexually active adolescents and young adults. As an example, in the United States, the rate of reported cases of chlamydia among women are highest among 20 to 24 year olds, followed by 15 to 19 year olds. In 2013, the incidence of chlamydia in these age brackets was 3621 and 3043 cases per 100,000 persons, respectively, compared with the total incidence of 623 cases per 100,000 persons . The incidences of chlamydia in males and gonorrhea in both genders are substantially lower but follow the same general age pattern.
In the United States, there are also geographic and racial differences with regards to STI prevalence . The southern states tend to have the highest rates of STIs nationally, although rates of syphilis are also relatively high in western states. Individuals of black race have a higher prevalence of STIs compared with other races.
Sexual history — In the assessment of sexually transmitted infection (STI) risk, it is important to obtain a thorough sexual history including:
•Any new sexual partner
•History of multiple sexual partners
•Sexual partners with concomitant partners
•History of sexual intercourse with trauma (as an example, fisting in MSM has been linked to increased risk of acquisition of hepatitis C virus infection)
•Anatomic sites of exposure (this will guide decisions about which mucosal sites to test diagnostically)
●Protection from STIs
•Frequency of condom use
●Past history of STIs
•History of any STIs, including genital ulceration, which can increase the risk of HIV acquisition
The history should be straightforward and non-judgmental with appropriate counseling regarding risk-taking behaviors, as necessary . Some medical providers do not routinely obtain a sexual history. In one study, only 70 percent reported "always" or "almost always" obtaining a sexual history in adolescent females . One reason for this omission may be related to provider comfort with this part of the patient interview . Suggestions for open-ended, non-judgmental questions, as suggested by the Centers for Disease Control and Prevention (CDC), are found in the following table (table 1) .
SCREENING RECOMMENDATIONS — Screening recommendations vary by gender, age, and sexual behavior (table 2).
●We recommend screening for HIV infection in all adults and adolescents aged 13 to 75 years. All individuals who seek screening for sexually transmitted infections (STIs) should receive testing and counseling for HIV infection. This provides an opportunity for risk reduction education, as well as diagnosis of HIV infection. (See "Screening and diagnostic testing for HIV infection".)
●Although all sexually active individuals are at some risk of STIs, screening for all STIs in all patients is not practical. Thus, screening for STIs focuses on those who are at high risk. For some STIs, this is done by targeting specific risk groups that have a high prevalence for STIs (eg, females <25 years old, men who have sex with men [MSM], HIV-infected patients, and individuals entering into correctional facilities). In other cases, screening is dependent on assessment of an individual's personal risk based on behavioral factors. Clinicians should also consider the characteristics of the communities they serve when determining appropriate screening strategies for their particular patient population. Local public health authorities can be a source of valuable information regarding local patterns of infection and disease prevalence. (See 'Assessing risk' above.)
●The optimal interval for screening of STIs is uncertain. For individuals with prior negative screening tests, the interval for re-evaluation will be influenced by persistence or change in risk factor profile. Positive screening tests are a marker for risk and warrant more frequent testing. (See 'Rescreening and retesting' below.).
●All individuals whose sex partners had been diagnosed with an STI should undergo testing or presumptive treatment for that STI. These individuals should also be tested for other curable STIs and HIV. Issues related to the management of such sex partners are discussed in detail elsewhere. (See "Treatment of Chlamydia trachomatis infection", section on 'Management of sex partners' and "Treatment of uncomplicated gonococcal infections", section on 'Management of sexual partners' and "Trichomoniasis", section on 'Sex partners'.)
Females — Many screening efforts around sexually transmitted infections focus on females. Most chlamydial and gonococcal infections are asymptomatic or minimally symptomatic in women, and untreated can lead to serious complications, including pelvic inflammatory disease, infertility, complications of pregnancy, and chronic pelvic pain [2,11].
●C. trachomatis genital infection, annually
●N. gonorrhoeae genital infection, annually
●HIV screening, one time (or with greater frequency for those at high risk of infection)
Additionally, screening for cervical cancer and HPV vaccination, if not already received, is recommended in this age group. These issues are discussed elsewhere. (See "Screening for cervical cancer", section on 'Routine screening recommendations' and "Recommendations for the use of human papillomavirus vaccines", section on 'Recommendations for HPV immunization in females'.)
Approaches to screening for syphilis, Trichomonas, and hepatitis viruses are the same as for older women. (See '25 years and older' below.)
Screening recommendations for pregnant women and HIV-infected women are discussed elsewhere. (See "Initial prenatal assessment and first-trimester prenatal care", section on 'Sexually transmitted infection' and 'HIV-infected patients' below.)
25 years and older — For women 25 years and older, at least one-time screening of HIV infection is recommended, if not already performed, with more frequent screening recommended for those at risk for infection (table 2). Additionally, screening for cervical cancer continues for all women in this age group, and HPV vaccination, if not already received, is recommended up to age 26. (See "Screening for cervical cancer", section on 'Routine screening recommendations' and "Recommendations for the use of human papillomavirus vaccines", section on 'Recommendations for HPV immunization in females'.)
Screening for other STIs in this age group is reserved for sexually active women with risk factors for STIs [1-3]. Risk factors include new or multiple sex partners, sex partners with multiple concurrent partners, inconsistent condom use outside a monogamous partnership, previous or coexisting STI, or women who exchange sex for money or drugs. In such women, we screen for the following:
●C. trachomatis genital infection
●N. gonorrhoeae genital infection
●Trichomonas (in settings where the prevalence is high)
●Hepatitis B virus infection (if not vaccinated or vaccine status is not known), once, followed by vaccination in the susceptible
Hepatitis C virus (HCV) screening based on sexual risk is performed for those who have a sex partner with chronic HCV infection. Other indications for HCV screening are discussed elsewhere. (See "Screening for chronic hepatitis C virus infection", section on 'Our approach'.)
Screening recommendations for pregnant women and HIV-infected women are discussed elsewhere. (See "Initial prenatal assessment and first-trimester prenatal care", section on 'Sexually transmitted infection' and 'HIV-infected patients' below.)
Pregnant women — Intrauterine or perinatally transmitted STIs can have grave effects on pregnant women, their partners, and their fetuses. Pregnant women are routinely screened at the initial prenatal visit for HIV, HBV, syphilis, and (if <25 years or with risk factors) chlamydia and gonorrhea. Indications for repeat screening later during gestation and screening for other infections is discussed elsewhere. (See "Initial prenatal assessment and first-trimester prenatal care".)
Specifics on STI screening in HIV-infected pregnant women are discussed below. (See 'HIV-infected patients' below.)
Males — STI screening recommendations differ between men who have sex with only women and MSM.
Heterosexual males — We screen men who have sex with only women at least once for HIV (if not already performed), with more frequent screening for those at risk for infection (table 2). Otherwise, we do not routinely screen HIV-uninfected heterosexual men for STIs unless they have a history of STI or are seeking STI evaluation (see 'Individuals seeking STI evaluation' below). It is reasonable to screen heterosexual men at risk for STIs in areas of high prevalence (ie, at STI or adolescent clinics and correctional facilities) if resources allow.
Men who have sex with men — We routinely screen sexually active MSM for the following (table 2):
●C. trachomatis and N. gonorrhoeae genital infection
●C. trachomatis and N. gonorrhoeae rectal infection, for those with receptive anal intercourse in the prior year
●N. gonorrhoeae oropharyngeal infection, for those with receptive oral intercourse in the prior year
It is reasonable to perform screening on at least an annual basis given the high prevalence rates of these STIs in MSM. More frequent screening (eg, every three- to six-month intervals) is warranted for MSM at particularly high risk for STIs, including those with multiple or anonymous partners . Frequent HIV screening is also essential in high-risk MSM who are taking pre-exposure prophylaxis for HIV. (See "Pre-exposure prophylaxis against HIV infection", section on 'Patient monitoring'.)
In addition, viral hepatitides are frequent pathogens among MSM:
●Hepatitis A virus (HAV) — We perform one-time screening for evidence of infection or immunity in MSM who have not been previously vaccinated. If the patient is seronegative, immunization is indicated. (See "Hepatitis A virus infection: Prevention".)
●Hepatitis B virus (HBV) — We perform one-time screening for evidence of infection or immunity in MSM who have not been previously vaccinated. If the patient is seronegative, immunization is indicated. (See "Hepatitis B virus vaccination".)
●Hepatitis C virus (HCV) — We perform at least one-time screening given the mounting evidence of sexual transmission among MSM. At least annual HCV screening is recommended among HIV-infected MSM . More frequent screening may be warranted in specific circumstances (eg, high local HCV prevalence and incidence, high-risk sexual behaviors, and concomitant ulcerative STIs or STI-related proctitis). (See 'HIV-infected patients' below.)
MSM are also at risk for HPV infection and its associated conditions, including squamous intraepithelial lesions. Although data on the benefits of screening are limited, some experts screen MSM for HPV-associated lesions with anal cytology. This is discussed in detail elsewhere. (See "Anal squamous intraepithelial lesions: Diagnosis, screening, prevention, and treatment", section on 'Screening for anal SIL'.)
HIV-infected patients — High rates of STIs have been found through screening programs of HIV-infected patients worldwide [47,50,51]. Routine STI screening of HIV-infected patients in order to reduce the spread of STIs is warranted, particularly because STIs, in turn, can increase HIV transmission. Specifically, testing for the following infections is performed [1,5] (table 2):
●N. gonorrhoeae at genital sites (and for MSM, at rectal and pharyngeal sites if exposed), at initial evaluation then annually
●C. trachomatis at genital sites (and for MSM, at rectal sites if exposed), at initial evaluation then annually
●Syphilis, at initial evaluation then annually
●Trichomonas (for women), at initial evaluation then annually
●HAV (for MSM, those who are chronically infected with HBV and/or HCV, and injection drug users), at initial evaluation with vaccination if susceptible
●HBV, at initial evaluation with vaccination if susceptible
●HCV, at initial evaluation then at least annually, with more frequent testing depending on specific circumstances (eg, local HCV prevalence and incidence, high-risk sexual behaviors, and concomitant ulcerative STIs or STI-related proctitis)
In areas of high STI prevalence, biannual STI testing may be prudent. More frequent screening for gonorrhea, chlamydia, and syphilis is indicated in HIV-infected MSM who have multiple or anonymous partners, as well as in patients who exchange sex for money, drugs, or basic needs. (See 'Men who have sex with men' above.)
Pregnant HIV-infected women are tested for gonorrhea, chlamydia, syphilis, Trichomonas, and HBV at the initial prenatal visit. Those who have not had HCV screening or who are at risk for infection are also tested at the initial prenatal visit. Repeat testing is performed at the second or third trimester for those with ongoing risk.
HPV-associated cancers are also prevalent among HIV-infected patients and should be screened for. These issues are discussed elsewhere. (See "Screening for cervical cancer in HIV-infected women and adolescents" and "Anal squamous intraepithelial lesions: Diagnosis, screening, prevention, and treatment".)
Individuals seeking STI evaluation — Individuals who are seeking an STI evaluation often do so because of a specific exposure. In such cases, we screen for the following infections:
●Gonorrhea (at genital, rectal, and pharyngeal sites, according to exposure)
●Chlamydia (at genital and rectal sites, according to exposure)
●Trichomoniasis (in women)
●HSV-2 type-specific serology
At this time, neither the CDC nor the USPSTF recommend routine screening of women and heterosexual men for extragenital gonorrhea and chlamydia. However, in certain situations (eg, high prevalence settings and/or patients reporting only extragenital exposures), extragenital screening of women and heterosexual men can be a useful strategy to identify infections that would otherwise go undetected. Several studies suggest that the prevalence of extragenital infections in these populations are much lower than in MSM, but they are not negligible. As an example, among 4402 women accessing care at an STI clinic who reported extragenital exposures, 30 percent of gonorrhea cases and nearly 14 percent of chlamydia cases would have been missed with a genital-only testing approach . The numbers were similar for the 5218 men who reported only sex with women. Analysis of the numbers needed to screen to detect a single isolated extragenital gonococcal infection further highlighted that the biggest yield for extragenital screening is in MSM: 43 women and 69 heterosexual men versus 6 MSM would have to be screened to detect a single isolated extragenital gonococcal case.
Women who have sex with women — Screening recommendations for women who have sex with women (WSW) are the same as for the general female population based on age and risk factors. (See 'Younger than 25 years' above and '25 years and older' above.)
The risk of infection with STIs among WSW varies widely, depending upon number of partners, if the patient also has sex with men, and specific sexual practices. As an example, practices involving digital-vaginal or digital-anal contact, particularly with shared penetrative sex items, are a possible means for transmission of certain infections.
Although having female sexual partners has been associated with bacterial vaginosis (BV) in women, there are insufficient data to support routinely screening WSW for BV and it is unclear whether treating asymptomatic BV would improve long-term outcomes or decrease the risk of future symptomatic episodes .
STIs among WSW are discussed in detail elsewhere. (See "Medical care of sexual minority women", section on 'Sexually transmitted infection'.)
Transgender individuals — The term transgender includes individuals whose gender identity is different from the sex they were born with and/or whose gender expression does not fall within the stereotypical definitions of male and female. Thus, it refers to a diverse group of individuals, some of whom have their original anatomy and some who have had sex reassignment therapy. Additionally, gender identity does not dictate sexual behavior. Thus, screening for STIs in transgender individuals should take into account the individual's anatomy (ie, a transgender female to male may still have a vagina, cervix, and uterus and thus be at risk for HPV-associated cervical cancer and the sequelae of other bacterial STIs) and sexual practices.
Individuals in correctional facilities — Individuals entering into correctional facilities are more likely to have other risk factors for STIs, and the prevalence of STIs is high among this population. Being in a correctional facility also offers the opportunity to provide treatment and follow-up.
In the United States, the CDC recommends screening for chlamydia and gonorrhea in women ≤35 years and men ≤30 years old upon entry into a correctional facility. This recommendation is supported by surveillance studies that demonstrate high prevalence of these STIs in these populations [53-55].
Screening for syphilis depends on the community prevalence of syphilis. Local syphilis rates in the United States can be found through the CDC's syphilis surveillance site or by contacting the local health department.
SCREENING METHODS — Testing for sexually transmitted infections generally involves a blood test and/or self-collection of relevant body fluid specimens.
Testing for HIV is ideally performed with a combination antigen/antibody immunoassay, which requires a blood draw. At the point-of-care, other options for testing can be performed on oral secretions or finger stick samples. (See "Screening and diagnostic testing for HIV infection", section on 'Tests'.)
Testing for the following involves a blood sample:
●Syphilis — either a nontreponemal or treponemal test (see "Syphilis: Screening and diagnostic testing", section on 'Serologic tests')
●HBV — HBV surface antigen (HBsAg), surface antibody (HBsAb), and core antibody (HBcAb) (see "Diagnosis of hepatitis B virus infection")
●HCV — HCV antibody (see "Screening for chronic hepatitis C virus infection", section on 'Screening method')
Testing for other STIs can be performed on relevant non-blood specimens:
●N. gonorrhoeae — nucleic acid amplification testing (NAAT) on urine (preferred for men) or vaginal swabs (preferred for women), urethral swabs, endocervical swabs, rectal and oropharyngeal swabs (see "Clinical manifestations and diagnosis of Neisseria gonorrhoeae infection in adults and adolescents", section on 'Asymptomatic patients')
●C. trachomatis — NAAT on urine (preferred for men) or vaginal swabs (preferred for women), urethral swabs, endocervical swabs, and rectal swabs (see "Clinical manifestations and diagnosis of Chlamydia trachomatis infections", section on 'Diagnostic techniques')
●T. vaginalis — NAAT on vaginal swabs (preferred) or urine (see "Trichomoniasis", section on 'Nucleic acid amplification test')
The advent of urine-based tests and the utility of self-collected vaginal swabs has increased the acceptance of STI screening among patients and providers since it allows for routine specimen collection without a pelvic examination or swab of the urethra [51,56].
Screening for HPV-associated disease is performed by cytology and/or HPV testing of cervical specimens or cytology of anal specimens. (See "Cervical cancer screening tests: Techniques for cervical cytology and human papillomavirus testing", section on 'HPV testing'.)
MANAGEMENT OF POSITIVE SCREENING TESTS
Treatment of the STI — Management of sexually transmitted infections depends on the specific infection. Diagnosis of non-viral STIs generally should result in prompt treatment, since a few individuals may develop complications in the interval between screening and treatment . Specific treatment regimens for these infections are discussed in the dedicated topic reviews.
Considerations regarding treatment of HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) are found elsewhere. (See "When to initiate antiretroviral therapy in HIV-infected patients" and "Hepatitis B virus: Overview of management" and "Patient evaluation and selection for antiviral therapy for chronic hepatitis C virus infection".)
Health department notification — Local and state public health practices of partner notification and disease reporting are important, in addition to individual sexually transmitted disease case management. In the United States, notifiable infections include C. trachomatis, N. gonorrhoeae, acute HBV, acute HCV, HIV, and syphilis .
Partner notification — For gonorrhea, chlamydia, syphilis, and Trichomonas, sex partners should be notified, examined, and treated for the STI identified or suspected in the index patient . In some settings, expedited partner therapy (EPT) has been used for chlamydial and gonorrheal infections. With this system, the patient directly provides their sexual contacts with medications and prescriptions to be filled. EPT does not give the sexual contact a chance to ask questions, or receive counseling or additional STI screening, but does prevent recurrent chlamydial and gonococcal infections . In the United States, EPT is legal in most states. Refer to the CDC website for more details. (See "Treatment of Chlamydia trachomatis infection", section on 'Management of sex partners' and "Treatment of uncomplicated gonococcal infections", section on 'Management of sexual partners'.)
Patients with non-viral STIs and their sex partners should abstain from sexual intercourse until seven days after initiating treatment.
Rescreening and retesting — Because of high rates of reinfection, individuals who were diagnosed and treated for chlamydia, gonorrhea, and Trichomonas should be retested for the infection. Retesting is performed three months after treatment or at the first follow-up visit thereafter during the year following treatment. (See "Treatment of Chlamydia trachomatis infection", section on 'Retesting' and "Treatment of uncomplicated gonococcal infections", section on 'Retesting' and "Trichomoniasis", section on 'Follow-up'.)
The incidence of reinfection was examined in women and men who have sex with women who were evaluated for an STI at one of three urban STI clinics . Patients had follow-up visits scheduled at 3, 6, 9, and 12 months with the following results:
●Among 1236 women, 26 percent had acquired one or more new infections (including C. trachomatis, N. gonorrhea, and T. vaginalis).
●Among 1183 men, 15 percent had acquired one or more new infections (including C. trachomatis and N. gonorrhea).
●Of those with a new STI, 66 percent were asymptomatic.
SCREENING UPTAKE — Despite recommendations for routine and targeted screening, screening rates in the appropriate populations are suboptimal [18,61,62]. As an example, in the United States, an analysis of data provided from private and public health plans indicated that less than half of eligible women were screened for chlamydia, even with an overall increase in screening rates during the reporting period . Screening rates are likely lower among those without health insurance. In a trial of the effectiveness of a registry in the Netherlands inviting individuals aged 16 to 29 to participate in collecting home-based samples for chlamydia screening, participation was low (16 percent initially, which decreased over the three-year trial period), with no impact on the overall rate of chlamydia infection .
Screening uptake is also problematic in persons with HIV infection. In a multicenter study conducted in North America, annual gonorrhea and chlamydia testing was compared to syphilis and lipid testing among 19,368 HIV-infected adults (41 percent MSM, 30 percent heterosexual men, 29 percent women) engaged in care . In 2010, only 39 percent were tested for gonorrhea and chlamydia, compared with 77 and 76 percent for syphilis and lipid levels, respectively. Another study involving 4217 HIV-infected patients found that amongst those who were sexually active, 55 percent were tested at least once in 12 months for syphilis, but only 23 and 24 percent had a test for gonorrhea and chlamydia, respectively . Among HIV-infected MSM who were deemed to be at high sexual risk, 26 percent received repeat syphilis testing, and only 7 percent received repeat gonorrhea and syphilis testing.
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Sexually transmitted infections".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Chlamydia and gonorrhea (The Basics)" and "Patient education: Genital herpes (The Basics)" and "Patient education: Screening for sexually transmitted infections (The Basics)")
●Beyond the Basics topics (see "Patient education: Gonorrhea (Beyond the Basics)" and "Patient education: Chlamydia (Beyond the Basics)" and "Patient education: Testing for HIV (Beyond the Basics)" and "Patient education: Genital herpes (Beyond the Basics)" and "Patient education: Genital warts in women (Beyond the Basics)" and "Patient education: Hepatitis B (Beyond the Basics)" and "Patient education: Hepatitis C (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Complications of untreated sexually transmitted infections (STIs) include upper genital tract infections, infertility, chronic pelvic pain, cervical cancer, and chronic infection with hepatitis viruses and HIV. Many patients have asymptomatic disease, and screening for infection is thus an important approach to identify and treat infected individuals who would otherwise go undetected. (See 'Rationale' above.)
●Although all sexually active individuals are at some risk of STIs, screening for all STIs in all patients is not practical. Thus, screening for STIs focuses on those who are at high risk. For some STIs, this is done by targeting specific risk groups that have a high prevalence for STIs (eg, females <25 years old, men who have sex with men [MSM], HIV-infected patients, and individuals entering into correctional facilities). In other cases, screening is dependent on assessment of an individual's personal risk based on behavioral factors or the prevalence of infection in the local community. (See 'General principles' above.)
●Our screening recommendations are generally consistent with those of the United States Centers for Disease Control and Prevention. (See 'Screening recommendations' above.)
We screen all HIV-uninfected adults and adolescents at least once for HIV infection. In addition (table 2):
•For all sexually active females <25 years old, we screen for chlamydia and gonorrhea annually. Screening for syphilis, Trichomonas, hepatitis B virus (HBV), and hepatitis C virus (HCV) is reserved for those with other risk factors, as delineated for older women. (See 'Younger than 25 years' above.)
•For women ≥25 years old who have risk factors for STIs (eg, new or multiple sex partners, recent STI diagnosis, exchanging sex for money or drugs), we screen for genital chlamydia and gonorrhea, syphilis, Trichomonas (in settings where the prevalence is high), and HBV infection (if unvaccinated or of unknown status, with plans to vaccinate if susceptible). HCV screening is performed for those who have a sex partner with chronic HCV infection. (See '25 years and older' above.)
•For men who have sex exclusively with women, we do not routinely screen heterosexual men for STIs unless they have a history of STI or are seeking STI evaluation
•For MSM, we screen at least annually for syphilis, genital chlamydia and gonorrhea, rectal chlamydia and gonorrhea (in those who have had receptive anal intercourse in the prior year), and oropharyngeal gonorrhea (in those who have had receptive oral intercourse in the prior year). More frequent screening is warranted for MSM at particularly high risk for STIs, including those with multiple or anonymous partners. We perform one-time screening for hepatitis A virus (HAV) and HBV, with vaccination if susceptible, and at least one time screening for HCV. (See 'Men who have sex with men' above.)
For HIV-infected patients, we screen at the initial visit and then at least annually for chlamydia and gonorrhea, syphilis, Trichomonas (in women), and HCV. We perform one-time screening for HAV (in MSM, injection drug users, and patients with chronic hepatitis), and HBV, with vaccination if susceptible. (See 'HIV-infected patients' above.)
●Individuals who request an STI evaluation often do so because of a specific exposure. In such cases, we test for the following infections: gonorrhea (at genital, and if exposed, rectal and pharyngeal sites), chlamydia (at genital and, if exposed, rectal sites), syphilis, HIV, Trichomonas (in women), and HSV-2 by serology. (See 'Individuals seeking STI evaluation' above.)
●Screening for human papillomavirus (HPV) focuses on detection of oncogenic HPV infection and/or cytologic abnormalities that can be caused by persistent infection. Indications for screening for cervical and anal dysplasia associated with HPV are discussed in detail elsewhere. (See "Screening for cervical cancer" and "Anal squamous intraepithelial lesions: Diagnosis, screening, prevention, and treatment", section on 'Screening for anal SIL'.)
●Testing for sexually transmitted infections generally involves a blood test (for HIV, syphilis, HBV, HCV) and/or specimens of relevant body fluid (for chlamydia, gonorrhea, and Trichomonas), which can be collected by the patient or clinician. (See 'Screening methods' above.)
●A positive STI screening test warrants treatment of the STI, potential notification of the health department, partner notification and management, and decisions on retesting after treatment. (See 'Management of positive screening tests' above.)
ACKNOWLEDGMENT — The editorial staff at UpToDate would like to acknowledge Myron Cohen, MD and Heidi Swygard, MD, MPH, who contributed to an earlier version of this topic review.
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