The U.S. Food and Drug Administration issued an alert for one of Becton Dickinson's (BDX) coronavirus tests due to an increased risk of false positive results.
Shares of the Franklin Lakes, N.J., medical-supply company at last check slipped 1.1% to $247.75.
The test, designed to detect viral nucleic acid from the virus that causes covid-19, is in use in about 600 labs across the U.S., primarily hospital labs, the company said.
In one study, the FDA said, 3% of the results were false positive for the BD Max System test, which in April received emergency-use authorization from the regulator.
The BD SARS-CoV-2 Reagents for BD Max System test is designed to detect viral nucleic acid from the virus that causes covid-19 in upper respiratory specimens, such as nasal swabs.
"Consider any positive result presumptive from tests using the BD SARS-CoV-2 Reagents for the BD Max System," the FDA said. "Consider confirming with an alternate authorized test."
The FDA also advised clinical-laboratory staff and health-care providers to report any issues with using covid-19 tests to the FDA.
Becton Dickinson said in a statement that it had "received reports of elevated rates of potential false positive results from certain customers experiencing the issue when using the BD SARS-CoV-2 Reagents for the BD MAX System."
"Within these users the elevated rates represent a small subset of the positive results," the statement said.
"As part of our efforts to continuously improve our assays we approached FDA and communicated options available to further improve the performance of the BD SARS-CoV-2. We are currently discussing these options with FDA including the information and data required to support these changes."
Becton Dickinson is selling other types of tests for the coronavirus. On Monday, the FDA granted emergency-use authorization for a point-of-care test to diagnose coronavirus and deliver results in 15 minutes.