4B 4 Self-Collected Penile Swabs in a Clinic: How Do They Compare to Urethral Swabs for Accuracy for Detection of Neisseria Gonorrhoeae and Chlamydia Trachomatis?

Wednesday, June 11, 2014: 3:30 PM
Dogwood A
Charlotte Gaydos, MS, MPH, DrPH1, Mathilda Barnes, MS, CCRP1, Perry Barnes, BS1, Laura Dize, BS1, Yu-Hsiang Hsieh, PhD2 and Vincent Marsiglia, MT (ASCP), DLM (ASCP), MHA3, 1Department of Medicine, Division of Infectious Diseases, Johns Hopkins University, Baltimore, MD, 2School of Medicine, Department of Emergency Medicine, Johns Hopkins University, Baltimore, MD, 3BDC Laboratory, Baltimore City Health Department, Baltimore, MD

Background: Urethral swabs are preferred for the culture of gonorrhea in males and are also used for the diagnosis of chlamydia. Self-collected penile swabs can be used for nucleic acid amplification tests (NAATs) in males, but have not been compared to clinician-collected urethral swabs.

Methods: Men who were being cultured for the diagnosis of gonorrhea in the STD clinic were asked to volunteer to also collect a penile swab for a NAAT for gonorrhea (GC) and chlamydia (CT).  Clinician-collected urethral swabs for GC culture/Gram stain were placed into transport media for a NAAT.  Volunteers for the study were then asked to collect penile swabs for transport media for the same NAAT assay. GC culture results for gonorrhea were also determined.

Results: In an ongoing study, of 92 men approached in the clinic, 83 (90.0%) of men agreed to collect a penile swab. From paired specimens, test results indicated 10 (12%) were positive for GC and 14 (16.8%) for CT from penile swabs; 9 (10.8%) were positive for GC and 12 (14.4%) for CT from clinician-collected urethral swabs. Results from penile swabs and urethral swabs agreed except 1 sample was penile+/urethral- for GC and 2 samples were penile+/urethral- for CT. There was no significant difference between self-collected penile swab and clinician-collected urethral swab for NAATs (p=0.500 for GC; p=0.250 for CT). Two of the three discordant samples positive by the penile swabs only were confirmed to be true positives by another NAAT assay (1 GC and 1/2 CT). Of the 10 positive GC NAAT results, all 10 were positive for GC by Gram stain and culture.

Conclusions: Self-collected penile swabs appeared to be as accurate as clinician-collected swabs for the detection of GC and CT for NAAT assays and could expedite express visits in a busy STD clinic.