As the insert explains, by January 27, the CDC had tested 253 respiratory specimens from 102 people with possible new coronavirus infections, and there were some discrepancies in the results depending on the timing and type of sample. For example, one person’s buccal (inside of the cheek) swab sample and sputum sample tested positive, while a nasopharyngeal swab from the same day tested negative. Another person’s sputum sample taken 10 days after the onset of symptoms tested positive, but their oral and nasopharyngeal swabs from the same day were negative.
Some of the disparities here may come down to the method of collection. Sputum samples might lead to the most accurate results because sputum contains secretions from the lower respiratory tract, where there’s usually a higher amount of the virus, Kelly Wroblewski, M.P.H., medical technologist certified by the American Society for Clinical Pathology Board of Registry and director of infectious diseases with the Association Public Health Laboratories, tells SELF.
The level of precision when testing can also affect how well the test works. “This can be impacted by things like specimen collection,” Wroblewski says. “If you’re not collecting good-quality specimens, you can get poor-quality test results.” For example, if the health care worker doesn’t take a swab that goes far enough into the nostril, or they don’t make good contact with the throat to get a good sample, the results could come back as negative because the sample didn’t have enough viral particles—even if the person getting tested did have the new coronavirus.
Beyond that, as the CDC notes, in the early stages of infection, it’s possible for the test not to detect the virus in a sample. So, no, new coronavirus testing isn’t infallible—but it is a key tool in helping us to better understand and track the disease.
5. Why have I been hearing about testing delays and contamination?
Many infectious disease experts have expressed frustration with how new coronavirus testing has been rolled out, partly because of delays in making the tests widely accessible.
“It is unclear what the delay was, and there are numerous reports about whether the delay was a result of contamination of the test kits or problems with the design of the test. Or just delays in manufacturing,” Dr. Mina says.
About that possible contamination: On March 1, Axios reported that some of the CDC test kits may have become contaminated during the manufacturing process. According to the New York Times, this contamination led to inconclusive results. Trying to address that problem might have caused testing delays and definitely caused some confusion.
“[Communication] with the country’s laboratories [was] woefully inadequate in keeping us informed and up to date about what was happening,” Dr. Mina says. “This left many labs, like ours at Brigham and Women’s Hospital, wondering how to proceed.”
Reportedly, the issues have been resolved. On March 1, FDA commissioner Stephen Hahn, M.D., said in a statement: “Upon learning about the test issue from CDC, FDA worked with CDC to determine that problems with certain test components were due to a manufacturing issue. We worked hand in hand with CDC to resolve the issues with manufacturing. FDA has confidence in the design and current manufacturing of the test that already have and are continuing to be distributed. These tests have passed extensive quality control procedures and will provide the high-level of diagnostic accuracy we need during this coronavirus outbreak.”
Tens of thousands of test kits will reportedly be distributed to state laboratories, though the success of this process still remains to be seen, and, unfortunately, some damage has already been done. Community spread occurring from person to person in states across the country may have been at least somewhat prevented with more widespread testing, diagnosis, and preventive measures.
6. How much will getting tested for the new coronavirus cost?
It depends on the specifics of your situation. If you’re receiving a test that will be processed by the CDC or a public health lab, the test itself should be free. But you might be charged for new coronavirus tests that are getting processed by commercial labs. There are also other factors to consider.