In this post I link to and excerpt from emergency physician Dr Christine Zink’s Aug 25, 2020 Huffpost article, I Had COVID-19 But Tested Negative 5 Times. Here’s What You Should Know About Testing:
As an emergency physician, I’m often asked about the coronavirus. When I was exposed and my tests kept coming back negative, even I wasn’t sure what to think.
Here are excerpts:
Not so long ago, if you had a mild sore throat and nasal congestion, you probably weren’t worried that something sinister was brewing inside you. Most likely you would have appropriately diagnosed yourself with a common cold, purchased some decongestants and rested. If you developed a fever, you might have had influenza, but usually, you could safely assume that what you were experiencing was a temporary inconvenience rather than a life-threatening illness. It was just another virus. Brush it off, get back to work.
But now getting sick is viewed very differently.
Over the last few months, it has become clear that the symptoms of COVID-19 are numerous and include not only fever, cough and shortness of breath but also body aches, significant fatigue, diarrhea, nausea and loss of taste or smell. Because there are so many potential symptoms and combinations of symptoms ― and so much confusion about the disease in general ― more and more people are afraid that they might have a potentially devastating illness, and so they are seeking reassurance through medical experts and testing at earlier and earlier stages of their illness.
The author of the article, Dr. Zink, is an emergency medicine specialist as is her husband. Both regularly work with patients with COVID-19 infections. Her husband contracted COVID-19.
Her husband self-isolated in a hotel for infected health care providers.
Two days later Dr. Zink, while asymptomatic, received a rapid-antigen test* which was negative. She also, at the same time received a PCR viral test* which takes longer to get the results back.
*Coronavirus Testing Basics from the FDA: “Content current as of:
07/16/2020.”
Both the rapid-antigen test and the PCR viral test both came back negative but the patient was asymptomatic at that time.
This dual testing protocol is often initiated when there is a high suspicion that an individual has COVID-19 and the initial rapid antigen test is negative.
The next day, I developed a minor cough and chills. I knew something was not right, but I did not have a fever and I was unimpressed with my symptoms. I obtained a fourth COVID-19 test and, once again, it came back negative.
I knew tests can return false negatives and I knew that COVID-19 symptoms can continue to appear and worsen over time, so all I could do was continue to monitor how I felt.
Viral and antigen tests commonly used in hospital emergency departments detect active infection, whereas antibody tests are used to detect previous exposure or infection. However, if viral and antigen tests have weak sensitivity or are administered too soon, patients may receive false-negative results.
This concern was described by the Mayo Clinic Proceedings* in June. Internal and Emergency Medicine*published a case report of a 30-year-old man in China who had seven negative PCR tests before testing positive on day eight of his illness. Researchers from Johns Hopkins determined that testing for COVID-19 too early in the course of infection increases the possibility of a false-negative result. According to their study, published in the Annals of Internal Medicine*, there was a 67% chance of patients receiving a false-negative if they were tested within four days of contracting the virus. The study found that when the test was administered on the day of symptom onset, typically four days after becoming infected, the probability of receiving a false-negative dropped to 38%. Researchers noted that testing was more accurate when administered three to four days after symptom onset, but even then, the probability of receiving a false-negative was 20%. The New England Journal of Medicine*further described issues with COVID-19 testing and false negatives, ultimately concluding that “clinicians should not trust unexpected negative results (i.e., assume a negative result is a ‘false negative’ in a person with typical symptoms and known exposure).”
*Each of these links are to the articles that reference them. For more details on each article, see Links To Some Recent Articles On COVID-19 Testing
Posted on August 26, 2020 by Tom Wade MD
