The prevalence of Neisseria gonorrhoeae (GC) in young people, aged 15-24, was found to be 0.47% in a study carried out in the community.

Although not part of the National Chlamydia Screening Programme (NCSP), some areas under the programme provide screening for gonorrhoea as well. The number of tests for Chlamydia trachomatis (CT) and GC were obtained from five NCSP areas providing dual testing. Four areas introduced testing in 2007 and the fifth in 2008. Two of these areas were outside London and the rest within Greater London. The period of data collection was not stated.

A total of 219,412 samples were tested from the five programme areas. The percentage of CT-positive samples ranged from 2.7% to 9.2%, GC positivity ranged from 0.2% to 2.1% which is consistent with other prevalence studies. CT positivity was higher outside London but that of GC varied; one London programme area consistently had the highest CT and GC positivities.

There has been general concern about the false-positive GC nucleic acid amplification test (NAAT) results especially in low prevalence areas. Two of the four laboratories involved in the study perform supplemental testing and the remaining two use a retest strategy. It is especially important that confirmation of initially positive tests is carried out in low prevalence areas as low specificity will affect the positive predictive value of the test.

The overall prevalence of GC, excluding one high prevalence area, was 0.47% (99% CI: 0.42-0.52). If the CT testing target for 2010/2011 of 35% of 6 million young people were reached, the authors predict that up to 12,000 more cases of GC could be identified by dual testing. This compares with around 7,000 cases in this age group seen in GUM clinics in 2009 and 15,000 in all age groups.

There was a male to female ratio of 1:3 for positive samples, whereas in GUM clinics men predominate. More women tend to be screened under the NCSP compared with men and this may suggest an unmet need in accessing testing.

The number of NCSP areas offering dual testing is increasing. Traditionally, GPs have been referring suspected cases of GC to GUM clinics because of doubts about the sensitivity of conventional swabs used in primary care. The NAAT technology provides a more sensitive and specific way of testing for GC without the need for immediate processing. It also allows for self-taken vulvo-vaginal swabs in women and first-catch urine samples in men, avoiding intimate physical examination.

As the prevalence of GC is low, NAAT testing for GC in primary care would be more valuable for diagnostic testing than dual screening with chlamydia.

Dr Richard Ma