A sensitive new assay that detects Chlamydia trachomatis in less than 20 minutes may help many more patients in clinics and other point-of-care settings learn they have the bacterial infection and receive prompt treatment to prevent severe complications.
The assay uses recombinase polymerase amplification (RPA), a nucleic acid amplification technique that identifies C trachomatis directly from urine samples. Other nucleic acid amplification methods such as polymerase chain reaction are highly sensitive, but they’re time-consuming and require trained personnel and costly automated equipment to produce test results.
Having a rapid assay for use in sexually transmitted disease clinics and other point-of-care settings is important because the infection often is asymptomatic and therefore goes undiagnosed. Studies also show that among patients who are tested for C trachomatis, up to 50% never return for their test results or recommended treatment.
The infection may cause nongonococcal urethritis in men and a number of reproductive tract infections in women, including cervicitis and pelvic inflammatory disease. Left untreated, C trachomatis infection increases the risk of ectopic pregnancy and is a leading cause of infertility worldwide. About 5% to 10% of the population has the infection.
In their study appearing online today in the Journal of Molecular Diagnostics, researchers in Estonia reported results using the RPA assay to test urine samples from 70 patients—51 women and 19 men, all aged 18 to 25 years. C trachomatis infection is particularly prevalent among young adults up to age 25 years.
Test results showed the assay had a specificity of 100% and a sensitivity of 83%, meaning that it correctly identified negative test results 100% of the time and accurately detected positive results 83% of the time.
The researchers noted that other existing point-of-care tests for C trachomatis are 96% to 99% specific but sensitivity is only 10% to 40%. Such performance “has limited their wider use, and there is a clear requirement for more sensitive and cost-effective diagnostic platforms,” they wrote. The RPA assay, they concluded, “takes only 15 to 20 minutes and does not require expensive machinery, which makes it potentially applicable in point-of-care settings.”