How do the sensitivities of gonococcal tests compare depending on the type of specimen–urine, urethral, cervical or rectal swabs?

 Bottom line:  Sensitivity of nucleic acid amplification (NAA) tests of urine specimens is lower than that of cervical or urethral specimens.  NAA testing on rectal swabs has not been approved, however, two studies suggest the sensitivities may be similar to cervical and urethral swabs for symptomatic men and women 

According to information in DynaMed summaries for Gonococcal Urethritis, Gonococcal Proctitis, and Gonococcal Cervicitis:
 A systematic review compares the sensitivities of urine, urethral, and cervical swabs with various nucleic acid amplification tests.   Ann Intern Med 2005 Jun 7;142(11):914   RESULTS:

Test Sensitivity
Testing for gonorrhea in women
PCR (4 studies) 55.6% (urine); 94.2% (cervical)
Transcription-mediated amplification (1 study) 91.3% (urine); 99.2% (cervical)
Strand displacement amplification (1 study) 84.9% (urine); 96.5% (cervical)
Testing for gonorrhea in men
PCR (4 studies) 90.4% (urine);
96.1% (urethral)

Nucleic acid amplification testing has not yet been approve for use with rectal swabs although some labs have established specifications for testing rectal swabs.

One retrospective study (251 men, 105 women) did report a sensitivity for rectal swabs using the Aptima Combo 2 (AC2).of 91% for symptomatic men and 75% for asymptomatic men. Sex Transm Infect. 2012 Feb;88(1):27-31. 

A similar sensitivity was found in testing rectal swabs using the AC2 as reported in Sex Transm Dis. 2008 Jul;35(7):637-42.  For rectal specimens tested for gonorrhea, the sensitivity was 93%.

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About Amy

Clinical Informationist at EUH Branch Library
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