Rapid point of care (POC) testing for STIs: Advancing care and improving clinical workflow

• Traditional lab-based tests for diagnosis of sexually transmitted infections are intricate and have a long turnaround time.
• Inappropriate or missed treatment can occur while waiting for a laboratory diagnosis.
• Recent advances in point of care testing for sexually transmitted infections provide an opportunity to improve care.

Nucleic acid amplification tests (NAATs) have been the standard of care for the diagnosis of sexually transmitted infections (STIs), specifically chlamydia and gonorrhea, for over 15 years, due to their high sensitivity and specificity. However, these highly accurate NAATs have remained largely limited to the laboratory and can have several days turn around time before results are available to the clinician and patient.¹

In a recent webinar Rebecca Lillis, MD, from the Louisiana State University, Department of Medicine, discussed the challenges associated with not having same-day accurate results, and outlined how rapid point of care (POC) testing, enabling same-day results, could have multiple benefits for patients and clinics.

Dr. Lillis has reviewed many studies looking at syndromic management of sexually transmitted infections (STIs) concluding that, “the bottom line is many patients are treated incorrectly. They are either undertreated or overtreated for chlamydia and gonorrhea, in the absence of point of care testing.”

Symptomatic patients are often treated with antimicrobials before test results are received. This approach has been recommended in the past to ensure rapid treatment and to prevent the spread of infection, however, this can result in overtreatment if test results later come back negative. Also, patients presenting as contacts to STIs are often treated empirically while awaiting test results, resulting in frequent overtreatments. Unnecessary antimicrobial prescribing can be costly for the healthcare provider, and can also lead to possible adverse effects for patients, including potential side effects of antibiotics such as nausea, vomiting, diarrhea, or more serious allergic reactions like anaphylaxis. Antibiotics also alter a patient's microbiome and can result in bacterial vaginosis and yeast infections.2 At the population level, the consequences of overtreatment are dire: antimicrobial resistance caused by overtreatment is estimated to cost $USD 55 billion a year in the United States alone, and this problem is only growing.³

Without rapid POC testing, undertreatment of patients can also occur. The consequences of a delay in results using standard lab-based testing can be demonstrated by looking at a patient case study:

• A 24-year-old cisgender man presents to clinic for STI testing and has had four recent sexual partners
• He has no urogenital complaints, does not report any partner concerns, and has no abnormalities on exams, so his urine is sent for standard chlamydia and gonorrhea testing 
• Three days later, his urine results are positive for chlamydia, but it takes 10 days to reach him after his visit and arrange for treatment, by which time he reports a new female partner 

Delays in diagnosis and contacting the above patient resulted in undertreatment. The patient potentially spread chlamydia to a new partner, and treatment was delayed for his previous partners who may be infected. 

A further extension of undertreatment is those patients who are lost to follow-up. This occurs in up to 24% of positive chlamydia or gonorrhea cases in the US where despite considerable efforts to contact the patient treatment is never provided.4-6 Again, the patient could potentially continue to spread the infection to new partners, or the infection could progress and lead to further health complications.

Evidence indicates that there is an increase in appropriate treatment when rapid POC testing is used. Dr. Lillis cited two studies conducted in the US that demonstrated a benefit over the standard of care.

1. In a Washington DC Emergency department, one study found that 55% of patients were given empirical treatment in the standard of care group, compared to only 21.6% in the rapid test group⁷
2. A Grand Rapids, Michigan, Emergency department compared traditional testing with rapid diagnostic tests and found that appropriate initial treatment was received in 60% of patients in the traditional testing group and 72.5% in the rapid diagnostic test group. The rapid diagnostic test group was also treated much more quickly at a median of 5 hrs vs 23 hours for the traditional testing group⁸

Rapid STI tests meant that patients were more likely to be notified of results, more likely to notify partners of test results, and could be offered counseling before leaving the emergency department.

A further study at four sexual health centers in England estimated that over 95,000 inappropriate treatments might be avoided annually by using a POC test. They also estimated that with same-day diagnosis and treatment, 189 cases of pelvic inflammatory disease, and over 17,000 onward transmissions from STIs might be prevented annually.⁹

Dr. Lillis acknowledges that although the benefits of POC testing are clear, the question of how long patients are willing to wait for results in the clinic could present a challenge. This is a question that has been looked at in several studies.

• 89.4% of university student health clinic attendees in Birmingham, Alabama, were willing to wait up to an additional 20 minutes beyond the end of their visit¹⁰
• 61% of women from an STI clinic in Baltimore and a teen health clinic in Cincinnati, were willing to wait up to 20 minutes, 26% were willing to wait up to 40 minutes¹¹
• Only 21.4% of London STI clinic attendees were willing to wait for the results of a 90 minute test¹²

Based on the available data, Dr. Lillis suggested that “the sweet spot is probably as short as possible, but something 30 minutes or less would be more ideal”.

Dr. Lillis concluded that POC STI testing has the potential to replace standard laboratory tests for patients presenting with suspected chlamydia and gonorrhea. Rapid POC testing can reduce time pressure on healthcare providers and can improve clinic workflow through accurate diagnosis and less unnecessary treatment. There is less time spent trying to contact patients for treatment and fewer treatment visits. It also provides an opportunity for additional testing should the expected results not be seen. Dr. Lillis explained, “if you have a patient with a urethral discharge and their test result is negative for gonorrhea and chlamydia, you might want to get another specimen and send for additional tests.” 

On top of these benefits, for sites with delayed or limited access to lab-based testing, Dr. Lillis suggested these tests could be ‘game changers’.