21 May 2018

Point-of-care STI test could transform treatment

Clinical Communicable Disease Sex

A highly effective new point-of-care test for chlamydia and gonorrhoea could drive down transmission rates and antibiotic resistance if introduced into Australia. 

At the moment, laboratory results could take an average of 21 days to return to some practices, a delay that often created enormous challenges for doctors to follow-up with patients who might be highly mobile or live thousands of kilometres from the clinic, Dr Louise Causer, a medical epidemiologist and lecturer at the Kirby Institute, said.  

But Dr Causer and her team believe that incorporating the new molecular GeneXpert point-of-care test could “potentially transform management and control of these infections in many endemic settings”, amid new research showing its performance was on par with conventional nucleic acid amplification tests. 

While the test had been used to test for conditions such as tuberculosis in some low-income countries, this was the first time it had been evaluated for the STIs in a primary care setting, she said. 

Clinicians take either a urine or swab test as normal, feed it into the device, and return 90 minutes later for the result. 

While the device has been commercially available since 2013, studies have been in laboratories or with highly trained staff. To determine whether its efficacy held up in the real world, Dr Causer and her team introduced it into 12 primary healthcare services in remote communities. 

Patients who came in for STI screening had their specimens tested with both the point of care test as well as a conventional laboratory test, and the researchers said that there was “excellent concordance” across the almost 2500 tests clinicians performed.  

The researchers recognised that the 90-minute turnaround time for a result was still less than ideal, but called it an “extreme improvement” compared to what was currently available.

At the moment, clinicians in high-prevalence areas were often relying on syndromic management guidelines to diagnose and make treatment decisions, they said. 

As a result, many who were infectious but asymptomatic were often lost to follow up or left for weeks or months suffering from the infection and potentially passing it on, while at the same time individuals who wouldn’t need treatment were getting it, Dr Causer said. 

“The problem with that is that you are potentially using antibiotics in people who don’t need them, and you’re potentially increasing antimicrobial resistance,” she said.

The researchers are currently undertaking a cost-analysis and are hoping to secure a Medicare rebate for the test to make it sustainable. 

None of the researchers reported potential conflicts of interest. 

BMJ 2018, online 10 May