Introduction of Extra-Genital Self-Obtained Nucleic Acid Amplification Tests (NAAT) for Gonorrhea and Chlamydial Infection in MSM in An STD Clinic

Background:  NAAT for gonorrhea (GC) and chlamydial infection (CT) are more sensitive than culture; self-obtained specimens may increase clinic efficiency.   

Objectives:  To evaluate how the introduction of extra-genital NAAT testing, including self-obtained specimens, affected testing coverage and case-finding among MSM STD clinic patients.  

Methods:  Our STD clinic serially introduced extra-genital NAAT testing and self-obtained specimen collection in 2010-11. We compared the year prior to NAAT testing (baseline; 9/2009 – 8/2010) to the first 6 months of NAAT testing (NAAT) and the first 6 months of self-obtained specimen collection (self-obtained).  

Results:  Extra-genital testing coverage was unchanged over the three periods: baseline 83% (2743/3288); NAAT 82% (1435/1761); self-obtained 83% (1535/1840).  During the self-obtained period, 35% of 1535 tested MSM collected at least one self-obtained specimen; patients self-collected more rectal than pharyngeal specimens (32% vs. 17%, p<.00005). The percentage of tested MSM with ≥1 extra-genital infection was higher during the NAAT and self-obtained periods than during baseline (17% and 18.5% vs. 12.6%, p=.007). The percentage of GC or CT infected MSM diagnosed with only an extra-genital infection increased from the baseline to the NAAT period (48 to 58%, p=.002). This increase primarily reflected an increase in the percentage of all tested MSM diagnosed with rectal CT (6.8% vs. 10.5%, p<.00005).  After adjusting for symptoms and contact to GC/CT, self vs. clinician obtained specimen collection was not associated with test positivity.  The prevalence of urethral GC/CT remained stable between the baseline and NAAT periods (GC 6.7% vs. 6.2%, p=0.48; CT 5.5% vs. 5.0%, p=0.42).  

Conclusions:  NAAT testing for extra-genital GC/CT increases case-finding compared to culture-based testing.  In our clinic, self-obtained specimen collection is acceptable to many MSM and appears to have similar sensitivity to clinician-obtained specimens.   

Implications for Programs, Policy, and Research:  NAAT should be used to test MSM for extra-genital GC/CT. Self-obtained specimens may increase clinic operational efficiency, but further programmatic evaluation is needed.