Self-obtained samples show similar performance as lab diagnostics for gonorrhea, chlamydia testing
Vaginal swab samples collected by patients performed similarly to lab-based molecular diagnostics for chlamydia and gonorrhea testing, therefore supporting the use of a new 30-minute point-of-case assay, according to findings published in JAMA Network Open.
“The new binx io CT/NG assay can facilitate a complete paradigm shift in how we offer testing for the two most commonly reported notifiable diseases in the United States — chlamydia and gonorrhea,” Barbara Van Der Pol, PhD, MPH, professor of medicine and public health at the University of Alabama at Birmingham and president of the American STD Association, told Healio. “Rates of infection with chlamydia and gonorrhea continue to rise, suggesting the need for additional tools in order to effectively reduce the burden of disease. Providers can now identify and treat infections (that are predominately asymptomatic) during a single office visit to prevent transmission and development of sequelea.”
Van Der Pol and colleagues conducted a prospective cross-sectional study from Sept. 18, 2018 through March 13, 2019, to compare commercially available diagnostic assays with a 30-minute point-of-care assay — the binx health io CT/NG assay. They collected vaginal swab samples from women and first-catch urine samples from men STI, HIV, family planning and obstetrics and gynecology clinics that performed routine STI screening. The researchers included only patients who were eligible for diagnostic testing or STI screening who had not taken antibiotics for gonorrhea or chlamydia in the past 28 days.
in total, Van Der Pol and colleagues obtained 1,523 samples from women (median age, 27 years) and 922 samples from men (median age, 29 years). More women than men presented with symptoms (53.6% vs. 33.4%). Samples were collected at 11 clinics in 9 geographical locations, including Baltimore, Birmingham, AL, Winston-Salem, NC, Houston, Indianapolis, Los Angeles, Jackson, MS, New Orleans and Philadelphia.
Sensitivity for the binx health assay for chlamydia was 96.1% (95% CI, 91.2%-98.3%) for women and 92.5% (95% CI, 86.4%-96%) for men. Specificity for chlamydia for the binx assay was 99.1% (95% CI, 98.4%-99.5%) for women and 99.3% (95% CI, 98.4%-99.7%) for men. The sensitivity for gonorrhea was 100% (95% CI, 92.1%-100%) for women and 97.3% (95% CI, 90.7%-99.3%) for men. Gonorrhea specificity estimates for the binx assay were 99.9% (95% CI, 99.5%-100%) for women and 100% (95% CI, 95.5%-100%) for men. Non-laboratory-trained individuals performed 94.8% of the tests overall.
“Sample-first collection by clients seeking sexual health care (or who are eligible for routine screening according to the CDC guidelines) immediately upon arrival at the clinic can enable rapid, accurate results that allow the provider to offer both accurate treatment and appropriate counseling,” Van Der Pol said. “This is the first truly rapid molecular assay for chlamydia and gonorrhea. It is a breakthrough development.”
However, obstacles still hinder STI screening efforts.
“When we think of reasons why people are not screened according to the recommendations — we screen only about 50% of eligible women who make an office visit in any given year — some of the barriers include lack of time, stigma related to asking about sexual health and loss to follow-up for treatment because of the time required for lab-based testing,” Van Der Pol said. “Testing with the binx io, especially when allowing patients to self-collect samples, can make this a routine part of an annual health care visit and reduce some of those barriers.”
Further studies that examine how to incorporate “this new paradigm of rapid testing” in clinical settings are needed, Van Der Pol added. – by Eamon Dreisbach
Disclosure: Van Der Pol reports that her institution receives research grants from Abbott Molecular, BD Diagnostics, BioFire, binx health, Cepheid, Hologic, Rheonix, Roche and SpeeDx. Please see the study for all other authors’ relevant financial disclosures.