Nucleic Acid Amplification Tests (NAATs) are the Recommended Urine Test for STI Screening
The recommended urine test for checking Sexually Transmitted Infections (STIs) is the Nucleic Acid Amplification Test (NAAT), which is the preferred diagnostic method due to its high sensitivity and specificity for detecting common STIs like chlamydia and gonorrhea. 1, 2
Advantages of Urine-Based NAATs for STI Testing
- NAATs are preferred for detecting Chlamydia trachomatis and Neisseria gonorrhoeae in both symptomatic and asymptomatic individuals due to their superior sensitivity compared to culture methods 1
- Urine-based testing is non-invasive, making it more acceptable to patients and increasing screening compliance compared to more invasive collection methods 2
- First-void urine specimens are considered the optimal specimen type for male STI testing, while vaginal swabs are slightly preferred for females (though female urine remains an acceptable specimen) 1, 3
- NAATs can detect infections even when patients are asymptomatic, which is crucial since most chlamydia infections and many gonorrhea infections produce no symptoms 1, 4
Specific Testing Recommendations by Population
For Males:
- First-catch (first-void) urine using NAAT is the recommended first-line testing method for all males, both symptomatic and asymptomatic 2
- For men who have sex with men (MSM), additional site-specific testing may be needed based on sexual practices (pharyngeal and rectal swabs) 2, 5
For Females:
- While vaginal swabs show slightly higher sensitivity (86% overall sensitivity), urine NAAT testing remains an acceptable specimen with good sensitivity 3, 6
- Female urine specimens have slightly reduced performance compared to cervical or vaginal swab specimens but are still recommended when less invasive testing is preferred 1, 6
Testing Protocol and Considerations
- Screening should be performed regardless of symptoms since most STIs are asymptomatic 1
- For optimal results, collect first-void urine (first part of the urine stream) rather than midstream urine 2
- Post-treatment testing should be scheduled at least 3 weeks after completion of antimicrobial therapy to avoid false results 2
- Retesting is recommended approximately 3 months after treatment due to high reinfection rates 1
Special Considerations
- For comprehensive STI screening in high-risk individuals, testing should include multiple anatomical sites based on sexual practices 5
- In sexual assault cases, NAATs may be used for urine specimens and vaginal swabs to detect STIs 1
- For MSM, the CDC recommends at least annual urine chlamydial NAAT for urethral infection if they have had insertive anal intercourse, and annual rectal swab testing for those who have had receptive anal intercourse 1
Urine-based NAAT testing has revolutionized STI screening by providing a non-invasive, highly sensitive method that can be used in various clinical and non-clinical settings, making it easier to implement widespread screening programs for early detection and treatment of STIs 4.