New report examines challenges and implications of false-negative COVID-
19 tests

Date:
June 5, 2020
Source:
The Geisel School of Medicine at Dartmouth
Summary:
In a new paper, researchers discuss challenges and implications
related to false-negative diagnostic tests for SARS-CoV-2 infection.



FULL STORY ==========================================================================
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, 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.

"Diagnostic tests, typically involving a nasopharyngeal swab, can be
inaccurate in two ways," explains lead author Steven Woloshin, MD, MS,
a 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. "A false-positive result mistakenly labels
a person infected, with consequences including unnecessary quarantine
and contact tracing. False- negative results are far more consequential
because infected persons who might be asymptomatic may not be isolated
and can infect others." In their paper, 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.

The researchers draw several conclusions from their work. "Diagnostic
testing will help to safely open the country, but only if the tests are
highly sensitive and validated against a clinically meaningful reference standard - - otherwise we cannot confidently declare people uninfected,"
says Woloshin.

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.

"Measuring the sensitivity of tests in asymptomatic people is an
urgent priority," says Woloshin. "A negative result on even a highly
sensitive test cannot rule out infection if the pretest probability --
an estimate before testing of a person's chance of being infected --
is high, so clinicians shouldn't trust unexpected negative results."
This estimate might depend on how common COVID-19 is where a person lives, their exposure history, and symptoms, he says.


========================================================================== Story Source: Materials provided by
The_Geisel_School_of_Medicine_at_Dartmouth. Original written by Timothy
Dean. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Steven Woloshin, Neeraj Patel, Aaron S. Kesselheim. False Negative
Tests
for SARS-CoV-2 Infection -- Challenges and Implications. New
England Journal of Medicine, 2020; DOI: 10.1056/NEJMp2015897 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200605140508.htm

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