Maryland hit a new high for the number of COVID-19 tests administered (“Maryland reports 549 newly confirmed coronavirus cases, 20 more deaths,” June 1). The Maryland coronavirus website reported 233,530 negative test results as of May 29. But the test results are only as good as the sensitivity and specificity of the test. According to recent medical literature, the value of negative results from the standard COVID-19 test are in question.
For example, the article, “The Appropriate Use of Testing for COVID-19” by Tony Zitek, M.D. (Western Journal of Emergency Medicine Volume 21, no. 3: May 2020), states at "this time, no peer-reviewed publications have reported a sensitivity and specificity of RT-PCR tests for COVID-19. One non-peer reviewed publication reports that, based on 87 Chinese patients who were ultimately diagnosed with COVID-19, pharyngeal RT-PCR tests have a sensitivity and specificity of 78.2% and 98.8%, respectively. The sensitivity was 62.5% for ‘mild’ cases. While no other publications currently provide estimates of the sensitivity and specificity, several peer-reviewed publications have provided evidence of a substantial false negative rate with RT-PCR swab tests.”
The 62.5% sensitivity suggests a false negative rate of up to 37.5%.
I encountered this problem after my husband and I became symptomatic. We were recently tested for COVID-19. The specimens were taken via oral swabs. We got our results within days. My husband tested positive, but I tested negative. We were advised by two medical professionals to assume, because I am symptomatic, that I am also positive and that my test result is a false negative. When my husband inquired about my getting retested, he was told that I cannot get retested because there are not enough available tests.
The cited article concluded, “While the exact sensitivity and specificity of RT-PCR tests for COVID-19 are not known, it appears that a positive test is highly suggestive of true COVID-19, but a negative test does not rule out the disease. Patients and providers in epidemic areas should assume they have the disease if they have the signs and symptoms of the disease even if their test was negative. The push for increased testing in areas that already have widespread COVID-19 may be overstated, as the benefits of large-scale use of a moderate sensitivity test are minimal.”
There is at this time no accurate measure of the standard RT-PCR test’s sensitivity. This calls into question the wisdom of basing public policy on the RT-PCR test because the possible high false negative rate makes a negative result meaningless.
Ed Schneider, Baltimore
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