Coronavirus Test Kits May Yield Inconclusive Results
Coronavirus Test Kits May Yield Inconclusive Results

Coronavirus Test Kits May Yield Inconclusive Results

Some US states are waiting for the CDC to send replacement enzymes necessary for carrying out SARS-CoV-2 assays.

Amy Schleunes
Amy Schleunes

A former intern at The Scientist, Amy studied neurobiology at Cornell University and later earned her MFA in creative writing from the University of Iowa. She is a Los...

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Feb 13, 2020


State laboratories have identified flaws in some of the test kits distributed by the US Centers for Disease Control and Prevention in an effort to speed up coronavirus diagnosis nationwide, according to Reuters. California and Georgia confirmed that they are waiting for the CDC to send new reagents while health authorities in Illinois say the kits are working fine and they are proceeding with testing.

Last week, the CDC began shipping roughly 200 kits to laboratories throughout the US and some 200 more to international labs, reports The New York Times. The agency says that 700 to 800 specimens from patients can be tested with each kit.

A trial run in some states produced “inconclusive” results that appear to have been caused by a defective enzyme, Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases, said during a press conference, according to Reuters. “Things may not always go as smoothly as we may like,” she added. Messonnier says the CDC will distribute a new supply of the faulty enzyme as soon as possible, reports the Times.

“The test is the only way you can definitely know you have the infection,” Jeanne Marrazzo, an infectious disease researcher at the University of Alabama at Birmingham, tells the Times. “You absolutely need it for case counting. It allows you to know who’s infected. You can treat those people, if a treatment is available, and you can isolate them.”

The Times reports that the testing kits are unreliable at detecting the coronavirus early on in the infection. For this reason, the CDC does not recommend testing people with no symptoms who may have been exposed to the virus.

There are now 14 confirmed cases in the US after a second person evacuated from Wuhan tested positive for the virus at a marine base in San Diego, according to Reuters. The patient had been placed under quarantine along with 232 other individuals who had been airlifted from China.

The coronavirus disease, now known as COVID-19, has infected roughly 60,000 people and resulted in more than 1,300 deaths.

Amy Schleunes is an intern at The Scientist. Email her at