Background TMA (Aptima Combo II) is unlicensed for the detection of chlamydia and gonorrhoea at extragenital sites but is increasingly used to screen MSM reporting receptive oral or anal intercourse as data accumulates to support its performance. We reviewed its value in screening our MSM cohort.

Methods The TMA and culture results of MSM receiving extragenital screening between 01/01/12 and 30/06/12 were retrospectively reviewed.

Results 565 MSM were screened (1042 extra-genital samples); 95 tested positive for at least one infection at one site.

111 positive TMAs were extragenital (detection rate 10.7%) amongst 87 patients. 68 patients had isolated extragenital infection.

41 MSM (8.5%) had rectal chlamydia, only 5 of whom had genital chlamydia; 7 were confirmed LGV.

8 (1.4%) MSM had pharyngeal chlamydia. 4 had concurrent rectal infection; none had urethral infection.

Urethral chlamydia was detected in 16 MSM (2.8%).

27 (5.6%) MSM had rectal gonorrhoea via TMA; 11 were positive on culture.

35 (6.2%) MSM had pharyngeal gonorrhoea via TMA; 8 were positive on culture.

12 (2.1%) MSM had urethral gonorrhoea; 11 were positive on culture.

Conclusion 15.4% MSM attending for tests had extragenital infection. 71.6% testing positive had isolated extragenital infection. Without extragenital TMA tests 49 chlamydia infections would have been missed or suboptimally treated, including 7 LGV.

25/52 cases of gonorrhoea would have remained undiagnosed had screening been by 3 site culture and urethral TMA.

Undiagnosed extragenital infection has implications regarding onward transmission of that STI and may result in missed/suboptimal treatment and partner notification. Failure to screen effectively may provide false reassurance and reinforce popular myths that the pharynx is not vulnerable to infection. This data supports our current practise of TMA testing at extragenital sites.