Evaluating multi-bug point-of-care tests for diagnosing STIs

New point-of-care (POC) tests are currently being developed which can be used in clinic to simultaneously test for multiple sexually transmitted infections (STIs). In work now published online in BMJ Open, we developed a model to compare three possible strategies for POC STI testing with the current practice of microscopy and lab-based testing. The three strategies were: 1) a dual test for chlamydia and gonorrhoea; 2) a triple test which also tests for M. genitalium, and 3) a quadruple test which also tested for trichomoniasis. The model examined the overall costs, patient benefits and cost-effectiveness of these strategies. The full results of the economic evaluation including the article and supplementary material are available online.

The results showed that testing for STIs with either a dual, triple or quadruple POC test provided more patient benefit than current practice but may cost more. The quadruple POC test, for chlamydia, gonorrhoea, M. genitalium and trichomoniasis, offered the most patient benefit with 240,467 fewer return visits and 808 fewer onward STI transmissions in a cohort of nearly a million people, representing the annual number of symptomatic GUM attendees in England.

The quadruple POC test was the least expensive POC strategy relative to standard care – with an incremental cost-effectiveness ratio (ICER) of £36,585 per quality adjusted life years (QALY) gained, when taking the clinic’s perspective. When taking the commissioners’ perspective, who pay for the services delivered through tariffs, over £26 million in savings could be achieved using the 4-bug test, mainly because patients were treated appropriately on their first testing visit rather than having to reattend.

POC testing using a multiplex test could be a valuable addition to sexual health clinics. The would benefit patients and reduce unnecessary prescribing. There may be ways that clinics can reduce the cost to their service, for example by using in particular patient groups or redesigning services around the tests, thereby reducing staffing costs. The tests could also help clinics adhere to new BASHH guidelines which recommend testing for M. genitalium in all males with non-gonococcal urethritis (NGU) and in women with symptoms suggestive of pelvic inflammatory disease (PID) – particularly clinics which don’t currently have access to M. genitalium testing.

In 2017, Aquarius, in collaboration with Atlas Genetics and the Applied Diagnostic Research and Evaluation Unit (ADREU) at St Georges, University of London, were awarded a Phase 2 follow-on Innovate UK grant, based on the success of this Phase 1 work. Aquarius are currently developing evidence around the real-world impact of changes to the patient pathway for health services, and evidence to include in business cases to support the introduction of Atlas’ new 30-minute chlamydia and gonorrhoea diagnostic test. The findings of this work will be published next year.

Aquarius have been involved in several projects assessing the economic impact of point-of-care testing. You can find more information about our previous projects on the Our Work page of our website. If you would like to find out how Aquarius can help you on a future project, please get in touch.