False-negative COVID-19 tests highlight need for testing accuracy
Infected people who test false-negative and are asymptomatic may not be isolated and can consequently go on to infect others.
As communities across the U.S. have struggled to cope with the effects of the COVID-19 pandemic, many have focused on the lack of widespread testing as a major barrier to safely reopening the country. As progress has been made on this front, the concern has shifted to testing accuracy, predominantly with antibody tests, which are designed to identify prior infection.
But according to a new Dartmouth-led paper published in The New England Journal of Medicine, more emphasis should be placed on addressing the inaccuracy of diagnostic tests, which play a key role in containing the pandemic.
WHAT'S THE IMPACT?
Diagnostic tests, which generally involve a nasopharyngeal swab, can be inaccurate in a couple of ways, according to lead author Dr. Steven Woloshin, professor of medicine and community and family medicine at Dartmouth's Geisel School of Medicine and of the Dartmouth Institute for Health Policy and Clinical Practice.
For one, a false-positive result mistakenly identifies someone as being infected, which can lead to consequences including unnecessary quarantine and contact tracing, with the latter needlessly eating up resources that are required to track the progression of the disease.
False-negative results, by contrast, are much more impactful because infected people who are asymptomatic may not be isolated and can consequently go on to infect others.
Woloshin and his colleagues discuss factors contributing to the current limitations of diagnostic tests – including variability in test sensitivity and the lack of a standard process for validating test accuracy – and also cite several large studies whose frequent false-negative results are cause for concern.
They conclude that diagnostic testing will only help with a safe reopening if it's highly sensitive and validated against a clinically meaningful reference standard. The FDA should also ensure that test manufacturers provide details of their tests' clinical sensitivity and specificity at the time of market authorization. Tests without such information will have less relevance to patient care.
THE LARGER TREND
Hospitals have been struggling with insufficient tests since the beginning of the coronavirus pandemic in the U.S., which is widely thought to have hindered broader virus mitigation efforts. Severe shortages of testing supplies and extended waits for results have limited hospitals' ability to monitor the health of patients and staff.
While shortages are not as pronounced as they once were, hospitals continue to struggle in other ways, particularly as shrinking margins force many organizations to rethink their business models or even lay off employees.
Twitter: @JELagasse
Email the writer: jeff.lagasse@himssmedia.com
