Chlamydia and gonorrhea are the most common and second most common notifiable diseases in the United States, respectively.¹ Rates of both sexually transmitted infections (STIs) have been increasing in recent years.1 Emergency physicians are on the front lines of diagnosis and treatment of these infections. The ACEP Public Health and Injury Prevention Committee recently issued an information paper on best practices for diagnosing chlamydia and gonorrhea in adult and adolescent patients. Here are highlights from the most current and evidence-based recommendations.

Testing for chlamydia and gonorrhea may be warranted in a range of circumstances, and clinicians should take into consideration patient, provider, and test characteristics when determining how to proceed. Patients with symptoms of infection (whether genital, extragenital, or disseminated), sexual contact with infected individuals, and high-risk demographics may all require testing. Empiric treatment based on clinical suspicion is reasonable when test results are not readily available and/or when follow-up is unlikely. In addition, patients diagnosed with chlamydia or gonorrhea should be offered testing for other STIs, such as syphilis and HIV. Of note, test of cure (ie, attempts to detect therapeutic failure) is generally not necessary.

Historically, microbiological culture was the gold standard for diagnosing chlamydial and gonorrheal infections. This method has been largely replaced by nucleic acid amplification tests (NAATs), which have sensitivities of up to 100 percent and specificities of 97 percent for diagnosing chlamydia and gonorrhea.² For chlamydia testing in women, endocervical and vaginal swabs likely perform equivalently. However, both are superior to urine specimens in terms of sensitivity.³ Interestingly, self-obtained vaginal swabs perform as well as clinician-obtained swabs and are generally preferred by patients.⁴ In men, urine specimens (ideally first-catch) perform at least as well as urethral swabs while maximizing patient comfort.^3,5

For gonorrhea testing in women, endocervical swabs appear to perform best, while in men, urine specimens are nearly as good as urethral swabs.^6,7 Gram stain from a urethral swab is an option for confirming the diagnosis in symptomatic men but not for excluding it.³ NAATs can be used to evaluate for both chlamydial and gonorrheal extragenital infections, though not all are approved by the U.S. Food and Drug Administration for this purpose. Finally, microbiological culture is still useful in determining antibiotic susceptibility when gonococcal resistance is suspected.

Development of improved point-of-care testing for chlamydia and gonorrhea is underway and has the potential to improve the diagnostic and therapeutic capabilities of emergency physicians in this area.  

Dr. Barron, Dr. Liang, Dr. Weber, and Dr. Josephson are members of the ACEP Public Health and Injury Prevention Committee.

References

1. Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2016. Atlanta: U.S. Department of Health and Human Services; 2017.
2. LeFevre ML. Screening for chlamydia and gonorrhea: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014;161(12):902-910.
3. Papp JR, Schachter J, Gaydos CA, et al. Recommendations for the laboratory-based detection of Chlamydia trachomatis and Neisseria gonorrhoeae. MMWR Recomm Rep. 2014;63(RR-02):1-19.
4. Hobbs MM, van der Pol B, Totten P, et al. From the NIH: proceedings of a workshop on the importance of self-obtained vagina specimens for detection of sexually transmitted infections. Sex Transm Dis. 2008;35(1):8-13.
5. Gaydos CA, Ferrero DV, Papp J. Laboratory aspects of screening men for Chlamydia trachomatis in the new millennium. Sex Transm Dis. 2008;35(11 suppl):S45-S50.
6. Knox J, Tabrizi SN, Miller P, et al. Evaluation of self-collected samples in contrast to practitioner-collected samples for detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis by polymerase chain reaction among women living in remote areas. Sex Transm Dis. 2002;29(11):647-654.
7. Cook RL, Hutchison SL, Østergaard L, et al. Systematic review: noninvasive testing for Chlamydia trachomatis and Neisseria gonorrhoeae. Ann Intern Med. 2005;142(11):914-925.