April 10, 2020
Press Release

WASHINGTON - Today, Congressman Ted W. Lieu (D-Los Angeles County) sent a letter to CDC Director Redfield in response to reports of high rates of false negatives returned by coronavirus test kitsIn a February hearing, Congressman Lieu asked Director Redfield several times about the error rate for Covid-19 tests. Director Redfield assured Members the test kits worked. Subsequent media articles appear to contradict Director Redfield’s assurances. The letter seeks clarity from the CDC about the accuracy of coronavirus testing and requests the CDCto address reports of false negative results.

In the letter, the Mr. Lieu writes:

Dear Dr. Redfield, 

Thank you for your service. I write in regard to recent reports of alarmingly high rates of false negatives that are returned by coronavirus test kits. While the particular nature of COVID-19 makes it difficult to identify positive cases until many days after initial infection, the CDC must ensure it is doing all it can to increase the likelihood of detection as early as possible. That means holding test kit manufacturers and labs accountable to the highest standard

As you know, “missing cases” due to false negatives can have dire consequences. They effectively give patients the green light to interact with others, further spreading the disease among those closest to them. They also skew infection and mortality data.  

During a hearing on February 27, I specifically asked you about the potential for false negatives to hamper our ability to combat the virus, citing a February 25, 2020 Washington Post article titled, “A Faulty CDC Coronavirus Test Delays Monitoring of the Disease’s Spread.” Here is a transcript of our exchange, condensed for clarity, in which you assured me that the CDC’s test kits work: 

Ted LieuDoes the CDC’s test for coronavirus work? 

Dr. RedfieldYes. 

Ted LieuWhat is the error rate on that test? 

Dr. RedfieldWell, the problem was that when the tests were sent to the states one of the components had a contaminant in it... 

Ted LieuHas the CDC fixed it? 


Dr. RedfieldIt has been corrected –  

Ted LieuOK, so in fact the first test didn’t work. 

Dr. RedfieldThe first test works because it was developed at CDC, and it works fine. We test every one in the country. When the manufacturers scaled to send to the states, when the states got it…because of one of the contaminants in the control, there was another group that was – we don’t know if it was positive or negative. It was inconclusive. And at that time, the FDA requested that we not use that test – 

Ted Lieu: Okay, so the current test works? 

Dr. RedfieldThe current test works. 

Ted Lieu: Okay, great.  


Despite your assurances, a Wall Street Journal article from April 2, 2020 cites experts who believe that up to one in three infected individuals are potentially receiving negative test results. 

I am concerned that we do not have robust insight into the reliability of tests developed by manufacturers and lab companies. The article reports that the FDA initially required companies to submit to rigorous testing, but the requirements were later relaxed allowing labs to start testing without approval and letting them submit internal studies later. While I understand the need to balance oversight and testing with a rapid response to the virus, we cannot afford a 33% false positive rate for test results. 

I thus request answers to the following questions: 


  1. What does the CDC believe the error rate is for COVID-19 tests in the United States?
  2. What requirements do test manufacturers and labs have to meet in order to be eligible for partnership with the CDC’s coronavirus mitigation efforts? 
  3. Why did the CDC assure Congress the second test was “fixed” despite the high rate of false negatives? 
  4. What is the CDC doing now to improve the accuracy of results?  


I appreciate your attention to these matters and look forward to your response.  


Ted W. Lieu 
Member of Congress