Chlamydia screening has been rolled out nationally since 2007. Overall prevalence remains high and chlamydia is still a major public health issue, thus screening will continue for years to come.
Though screening is offered in a variety of community settings, the majority of tests are carried out in the core services (community reproductive and sexual health clinics, pharmacy and general practice).
A study in south-west England showed that young people prefer to be tested at their local general practice, a place they trust and feel comfortable in.1 There has been an increase in the number of young people screened in general practice, with 220,000 being tested in the year ending March 2011.
Overall, GPs undertake 12.8% of chlamydia screening; in London the proportion is 19% and in Lambeth PCT, south London, it is as high as 45%.2 This shows GPs are well placed to offer chlamydia testing and make it a success.
Who and how to test
Those at risk are young people who have had more than two sexual partners. The highest prevalence is among those aged 16 to 24 years; it is recommended these individuals be tested at least once a year or after each change of partner, even if they use condoms.
Chlamydia trachomatis infection is usually asymptomatic. For this reason, opportunistic screening is an important tool in controlling it. Although half of infections clear on their own, persistent infection can lead to PID, tubal infertility and ectopic pregnancy.
If a woman is infected during pregnancy, it can lead to premature rupture of the membranes and eye infection or pneumonia in the newborn.
The nucleic acid amplification test (NAAT) has a very high sensitivity (90-97%) and specificity (99%) and is the gold standard; all local NHS laboratories offer this test. It does not rely on culture, so turnaround is rapid, often 48 hours. The test detects RNA and DNA and therefore samples do not need refrigeration.
For men, a first void urine test is the main choice as long as the patient has not passed urine in the previous 20 minutes.
For women, a self-collected lower vaginal swab is the preferred method of choice. It is important to explain that the patient does not have to be examined by a doctor or nurse, and that they can take the sample in the practice toilet.3
A first void urine test is the main choice for men (Photograph: SPL)
Urine tests are also available for women and endocervical swabs are a third option in cases where the woman also needs speculum examination because it can be done at the same time.
It is important to encourage patients to do the test within the consultation time rather than at home - even with the best intentions, the return rate for home testing is very low.
I ask patients to produce a sample while I write up the notes, print off a prescription or fill out the form. In my practice the form is electronic and the results come back online, often within 48 hours.
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Treating chlamydia
Azithromycin 1g immediately is the treatment of choice and the single dose means compliance is high. Doxycycline 100mg twice daily for seven days is a good alternative. In pregnancy, erythromycin 500mg twice daily for 14 days is recommended because azithromycin is not licensed for use in pregnancy.
Abstinence from sex for seven days is important and partners should be tested and treated. Most GPs are concerned about this aspect of management.
Research has shown that most patients prefer to tell partners themselves. If you feel unsure about this, you can refer the patient to the GUM clinic to help with partner notification.
Though treatment with azithromycin is very effective, reinfection rates can be high owing to further sexual intercourse with untreated partners.
Patients who test positive for chlamydia may also be at risk of other STIs, many of which can be tested for in general practice (including syphilis, HIV and hepatitis B). In addition, a high vaginal swab should be taken to check for trichomonas and gonorrhoea, although some laboratories do dual testing for chlamydia and gonorrhoea.
Opportunities for testing
GPs see young people for a variety of reasons, from acne, asthma and eczema to sports injuries or contraception. Each of these consultations can be used by the GP or practice nurse to discuss chlamydia screening and offer a test.
Practices screening large numbers of young people involve the whole team, from the receptionist and healthcare assistant to the practice nurse, salaried GPs, locums and senior partners. It is a great help to have computer reminders, or to add chlamydia screening to a contraception template.
Chlamydia trachomatis infection remains highly prevalent and screening young people aged 16 to 24 years is recommended. Testing is accurate and patient-friendly, and treatment is very effective.
It can be very rewarding for GPs to manage a patient testing positive for chlamydia.
- Dr Kalwij is a GP in Lambeth and a GP lead for chlamydia screening in Lambeth
References
1. Hogan AH, Howell-Jones RS, Pottinger E et al. '... they should be offering it': a qualitative study to investigate young people's attitude towards chlamydia screening in GP surgeries. BMC Public Health 2010; 10: 616.
2. National Chlamydia Screening Programme scorecard www.chlamydiascreening.nhs.uk/ps/assets/pdfs/data/ NCSP_Scorecard_Q1_2011_12.pdf
3. Kalwij S, Macintosh M, Baraitser P. Screening and treatment of chlamydia trachomatis infections: BMJ 2010; 340: c1915.
