National audit of asymptomatic screening in UK genitourinary medicine clinics: clinic policies audit

INTRODUCTION

Screening asymptomatic patients for common sexually transmitted infections is part of core management in UK genitourinary medicine (GU) clinics for which there are clinical guidelines ¹ against which practice can be audited. This paper accompanies the report on the case-notes part of the British Association for Sexual Health and HIV (BASHH) audit of asymptomatic screening in UK GU clinics. ²

OBJECTIVE AND GOAL

The objective was to measure the level of adherence to the UK National Guidelines, ² which includes recommendations for asymptomatic screening, and the goal of the audit was to improve asymptomatic screening in the UK.

METHODS

The audit methodology and organization is described in the accompanying paper. ² This report provides overall national performances, as well as the ranges of regional performances expressed as percentage values, and allows comparisons of clinic policy on asymptomatic screening to be made against the recommendations in the National Guidelines. ¹ The questionnaire, which is available on the BASHH website (see below), enquired about each clinic's policy regarding tests that were offered routinely to all asymptomatic patients, and also if any of the tests listed would be offered routinely regardless of the sexual history. Clinic policies for testing for trichomoniasis were not asked about. Detailed data on regional performance, allowing comparisons between regions, are posted on the BASHH website (http://www.bashh.org/committees/nag/index.htm).

RESULTS

The results given are the total national figure (%) and regional ranges in percentages.

DISCUSSION

This response rate of just over half of clinics limits the overall conclusions that can be drawn about policies on asymptomatic screening for sexually transmitted infections in UK GU clinics. In particular, it is likely that clinics seeing a smaller number of patients were under-represented. Also, non-response by clinics may have introduced selection bias, with good performance being non-representative if non-responding clinics did not have policies in keeping with the guidelines. No information was collected about clinic systems, and the audit was not designed to account for differences in clinic performance in different geographical locations or settings. This work is the remit of the BASHH Regional Audit networks ³ and includes comparison of performance between clinics in a region. Clinics with good performance in an area of practice should share systems and processes that support good performance and allow learning by other clinics. Future audits should gather data on numbers of cases seen, and increase participation from smaller clinics. There is further discussion about the response rate in the case-notes audit report. ²

All but two clinics responding had a policy of offering an HIV test to all patients attending for asymptomatic screening, in keeping with the Department of Health standard that 100% of clinics offer HIV testing. ⁴ The recommendations for screening for syphilis in asymptomatic patients ¹ follow the BASHH Guidelines for management of syphilis, ⁵ which state: ‘Recommended for screening: Treponemal EIA (preferably a test that detects both IgG and IgM) or TPPA or VDRL/RPR and TPHA and confirm a positive screening test with a different treponemal test.’ Hence only two clinics (those not offering VDRL/RPR tests with TPHA testing) could be said to be non-compliant with the guidelines. Nearly all clinics had a policy of offering hepatitis B screening to asymptomatic MSM with either hepatitis B anti-core antibody or surface antigen, either of which are acceptable primary screening tests.

Regarding chlamydial screening, the guidelines ¹ advise that a chlamydia NAAT is the test of choice from either the urethra or urine in both heterosexual men and MSM, and from the endocervix or vagina (by a self-taken tampon or swab) in women. NAATs are not recommended for oropharyngeal specimens, and only for rectal tests in MSM who are contacts of lymphogranuloma venereum, although guidance for more widespread rectal screening for chlamydia in MSM men is stated in the guidelines ¹ to be under review. All clinics responding had a policy of offering men urine or urethral chlamydial screening. The choice of urethral over urine NAATs for men in some clinics is interesting, but this audit did not obtain data that would help understand the factors influencing this choice. However, urine testing is a more acceptable test in men and is as sensitive as urethral testing, ⁶ so it is possible that laboratory systems, e.g. handling of urine specimens, may be among the factors influencing this preference. Clinic policies with regard to chlamydia testing for women show a wide variation, with over one half of clinics offering only one specimen for chlamydia NAAT testing, primarily performed on endocervical specimens. Also, the 45% of clinics that offer vulvovaginal chlamydia NAATs suggests considerable variation in clinical practice with regard to routine speculum insertion for chlamydial testing.

The guidelines ¹ advise that culture is the test of choice for gonorrhoea for mucosal specimens taken from the urethra, endocervix, rectum and oropharynx in men and women. The use of NAATs may be considered for samples taken from the rectum and oropharynx if culture is not available. In men, NAATs may also be used on urine if a urethral specimen is not available. This audit shows that the recommended test for gonorrhoea screening in heterosexual men and MSM, urethral culture, is used in 66% and 70% of clinics, respectively. For women, 68% of clinics offered the recommended test, endocervical culture. However, a large minority of clinics offer NAATs, and not culture, for gonorrhoea screening, with about one-third of clinics offering heterosexual men and MSM urine or urethral NAATs, and just over one quarter of clinics offering endocervical, vulvovaginal or urine NAATs for gonorrhoea screening in women. The audit did not enquire what further tests, if any, were used to confirm diagnoses made by these molecular methods. The reasons for the choice of NAATs over culture for gonorrhoea are not known, but availability of culture and other laboratory resources may influence this choice. The case-notes part of the audit ² discusses the importance of maintaining up-to-date information on gonorrhoea antibiotic sensitivity, for which culture is necessary.

The guidelines recommend rectal and oropharyngeal screening for gonorrhoea in MSM if indicated by the sexual history. However, about one-third of clinics routinely offer rectal and oropharyngeal screening for gonorrhoea in MSM regardless of sexual history. Additionally some clinics have a policy of screening these sites for chlamydia, even though oropharyngeal screening for chlamydia is not recommended and rectal screening is under review. It is possible that this practice is based on the expectation of detecting asymptomatic infection at these sites, and a recent study ⁷ has shown significant asymptomatic gonorrhoea and chlamydia at both the pharyngeal and rectal sites in a group of men in Canada that would not have been detected by urine or urethral testing alone. However, the Canadian study does not provide data on whether detailed sexual history taking would have selected these cases for oropharyngeal and rectal screening. With regard to UK practice, the case-notes part of the audit ² shows that screening from the throat and rectum for gonorrhoea, and the rectum for chlamydia, is commonly performed, with 80%, 70% and 58% of MSM having oropharyngeal and rectal cultures taken for gonorrhoea, and a rectal NAAT for chlamydia, respectively. There were higher rates of screening performed where there was a history of receptive sex at these sites. In women, these tests are rarely performed, irrespective of sexual history.

Urethral sampling for gonorrhoea or chlamydial infection in women is not recommended, but this is a common policy for gonorrhoea screening and is discussed in the case-notes part of the audit. ² However, although patient preference may determine the sample obtained for gonorrhoea screening in women, a policy of offering only urine NAAT testing for gonorrhoea cannot be justified because urine testing in women is an insensitive method. ⁵

The guidelines do not recommend a policy of routine urethral microscopy in asymptomatic men or women, although around one-fifth of clinics continue to offer this to asymptomatic men, as well as a small number that offer urethral microscopy to women. The reason for still performing urethral microscopy in men may well relate to the continuing controversy over the significance of asymptomatic non-specific urethritis. ⁸ Clinics that continue to perform urethral swabs for gonorrhoea in women may have been influenced by the classical study by Goh et al. ⁹ which found that 181/1148 (15.8%) of cases of gonorrhoea in women were diagnosed solely by urethral smears.

CONCLUSIONS

Ninety-nine percent of clinics that responded have policies in line with national guidance for screening for syphilis and HIV, and nearly all clinics offer a test for hepatitis B screening for MSM. Most clinics offer screening for chlamydia in keeping with the guidelines. ¹ However, about one-third of clinics use NAATs rather than culture for gonorrhoea urethral screening in men and endocervical screening in women. Further work is needed to investigate the factors influencing this choice of NAAT testing for gonorrhoea over culture, and to explore whether culture for gonorrhoea is necessary in every clinic, or if sentinel surveillance of gonorrhoea at selected genitourinary medicine clinics would be appropriate. Further investigation into the reasons for the use of urine NAATs for gonorrhoea detection is also warranted. Many clinics continue to perform routine microscopy that is not recommended by the guidelines, although this area of clinical practice remains controversial and deserves further investigation.

SUGGESTED AREAS FOR PRACTICE IMPROVEMENT/INTERVENTIONS

Those clinics that do not have a policy to offer tests for endocervical gonorrhoea, and clinics offering only urine NAATs for gonorrhoea in women, should review their policies for gonorrhoea screening in asymptomatic women. Clinics with policies to offer microscopy to all asymptomatic cases should review this practice.

Detailed data, aggregated by region, as well as the clinic policy questionnaire are available on the BASHH website: http://www.bashh.org/committees/nag/index.htm