The Centers for Disease Control and Prevention had a basic design flaw in the coronaviruses testing kits they developed in the early weeks of the swine flu.
An internal report that was published on Wednesday documented a design error that caused false positives in the test kits.
When no other tests were authorized, the distribution of faulty test kits set back health officials efforts to detect and track the virus.
It delayed the availability of more widespread testing. He said that it was important that they got to the bottom of what went wrong.
In January 2020, the C.D.C. developed a P.C.R. test. P.C.R. tests can detect the coronaviruses at very low levels and have been considered the gold standard for diagnosis.
The C.D.C. began shipping its test kits to public health laboratories in February. Many labs reported that the tests were not conclusive.
In February, the agency acknowledged that the kits were flawed, and in April, they said that poor manufacturing practices had resulted in the contamination of the test kits.
The results of the C.D.C. internal investigation are presented in the new paper.
The C.D.C.'s test was designed to detect three distinct regions of the virus's genetic material. The test kits contain a set of primers, which bind to and make copies of the target sequence, and probes, which produce a fluorescent signal when these copies are made, indicating that genetic material from the virus is present.
The probes need to bind to the target sequence and not to each other. That didn't happen in this case. One of the probes in the kit can sometimes be bound to one of the primers and produce a false positive.
It should have been caught in the design phase, according to a clinical microbiologist at the University of Southern California. That is one thing you check for.
Synthetic fragments of the virus's genetic material were found in the test kits. The synthetic sequences were manufactured at the same C.D.C. lab where the test kits were undergoing a quality analysis. The agency concluded that the test kits were probably contaminated there.
The agency may have violated standard manufacturing protocols, according to officials.
Experts said that the problems may have been a sign of an agency in a rush.
The president of the College of American Pathologists said that she was not surprised that the agency ran into some problems. I am not sure if they had ever been asked to ramp up production in this way.
The C.D.C. was forced to change the way they review tests after they had problems with early ones. The new test was tested in three public health laboratories.
The agency said it has implemented corrective measures since the initial Covid-19 test was rolled out.
During a public health emergency, the responsibility for developing diagnostic tests should be distributed more widely. Rather than relying on the C.D.C. to be the sole test developer, officials could also use clinical and commercial labs to create and deploy tests.
She said that it was great that there were additional checks in place, but what would you do if there was a new emerging pathogen? I don't think that's a viable model for responding to a epidemic.
