Test of Cure for Chlamydia in Non-Pregnant Adults
Test of cure is NOT recommended for non-pregnant adults who complete first-line therapy (azithromycin 1g single dose or doxycycline 100mg twice daily for 7 days) with recommended regimens, as cure rates exceed 97-98% and routine testing wastes resources while risking false-positive results. 1, 2
When Test of Cure is NOT Indicated
Non-pregnant patients treated with azithromycin or doxycycline do not require test of cure if they are asymptomatic after treatment, as treatment failure rates are extremely low: 0-3% in males and 0-8% in females. 2
The CDC explicitly states that test of cure should not be performed for patients treated with recommended regimens unless specific circumstances exist (detailed below). 3, 1
Testing before 3 weeks post-treatment yields false-positive results because nucleic acid amplification tests (NAATs) detect DNA from dead organisms that continue to be excreted after successful treatment. 3, 4, 5
When Test of Cure IS Indicated
Test of cure should be performed only in these specific clinical situations:
Pregnancy: All pregnant women must undergo test of cure 3-4 weeks (21-28 days) after treatment completion, regardless of regimen used, because pregnancy regimens (azithromycin, amoxicillin, erythromycin) may have lower efficacy than doxycycline. 3, 4, 6
Questionable therapeutic compliance: When adherence to the full treatment course is uncertain or cannot be verified. 3, 1
Persistent symptoms: If symptoms continue after completing the recommended treatment course. 3, 1
Suspected reinfection: When there is concern that the patient resumed sexual activity before completing treatment or with an untreated partner. 3, 1
Alternative regimens used: If erythromycin or other less efficacious alternatives were prescribed instead of first-line therapy, consider test of cure at 3 weeks. 3
Optimal Timing for Test of Cure (When Indicated)
Minimum 3 weeks (21 days) after treatment completion is required to avoid false-positive NAAT results from residual dead organisms. 3, 4, 5
Optimal window is 3-4 weeks (21-28 days) post-treatment, which allows adequate clearance of dead organisms while still detecting true treatment failures. 4, 6
All participants in one prospective study had negative NAATs by day 29 post-treatment, with median clearance at 7-8 days. 5
Testing performed earlier than 3 weeks has not been validated and can yield misleading positive results that do not represent viable infection. 3, 7
Critical Distinction: Reinfection Screening vs. Test of Cure
Rescreening at 3 months is distinct from test of cure and is strongly recommended for all women:
All women with chlamydia should be retested approximately 3 months after treatment to detect reinfection, which occurs in up to 39% of cases and confers elevated risk for pelvic inflammatory disease. 3, 1, 2
This 3-month retest should occur regardless of whether partners were reportedly treated, as most post-treatment infections result from reinfection. 3, 1
Women should be rescreened whenever they next present for care within 12 months, even if they believe partners were treated. 3
The CDC notes that adolescents are an especially high priority for this 3-month rescreening. 3
Common Pitfalls to Avoid
Do not perform test of cure in asymptomatic non-pregnant patients treated with recommended regimens—this wastes resources and may yield false-positive results requiring unnecessary retreatment. 1, 2
Do not test before 3 weeks post-treatment—NAATs will detect dead organism DNA and produce false-positive results that do not indicate treatment failure. 3, 4, 7
Do not confuse test of cure with reinfection screening—the 3-month retest is for detecting new infections from untreated partners, not verifying initial treatment success. 3, 1
Do not assume partners were treated—directly verify partner treatment, as the most common cause of "persistent" infection is actually reinfection from inadequately treated partners. 4, 1
Ensure 7-day sexual abstinence after treatment initiation and until all partners complete treatment, as resuming intercourse earlier allows transmission of organisms not yet fully cleared. 4, 1, 2