The U.S. Food and Drug Administration voiced caution over a widely-used coronavirus test on Thursday (May 14), saying it may be unreliable.
The Abbott Laboratories test is called ID Now -- and it was approved by the FDA in late March.
It delivers results within minutes and is used at the White House.
But the FDA said in a statement that while the test can still be used on patients, it could potentially produce inaccurate results.
The U.S. regulator added that it was still reviewing data on the test and working with Abbott to find other ways to study it.
Abbott has distributed nearly 2 million ID Now tests.
And on Wednesday, a separate, non-peer reviewed study by New York University researchers said the ID Now tests could be missing a third to nearly half of all positive cases.
And a study conducted by the Cleveland Clinic in April showed that while the test detected the virus in around 85% of cases -- that was still lower than some other coronavirus tests.
In its statement, the FDA said that while these studies did offer quote "important information, it should be noted these studies have limitations, including small sample size, potential design biases, or tests that may not have been executed according to the manufacturer's instructions for use."
Abbott has also criticized the studies, saying in a statement on Thursday that the number of patients tested in the NYU study was small -- and that the Cleveland study performed the test incorrectly.
Abbott also pointed to other studies showing a much higher accuracy rate for the ID Now tests.
One study done by a testing clinic in Detroit said the test was accurate 98% of the time.