The US Food and Drug Administration (FDA) has alerted clinical laboratory personnel and healthcare providers of the potential for false-positive results with Abbott Molecular’s Covid-19 test kits.

The two tests, Alinity m SARS-CoV-2 AMP Kit and Alinity m Resp-4-Plex AMP Kit are authorised by the FDA under emergency use authorization (EUA) for Covid-19 testing.

In May last year, Alinity m SARS-CoV-2 AMP kit obtained EUA, which was revised this August.

It is intended for use in Clinical Laboratory Improvement Amendments (CLIA) of 1988-certified laboratories to carry out moderate or high complexity tests.

The Alinity m Resp-4-Plex AMP test was authorised by the FDA in March for use in CLIA-certified labs to conduct moderate or high complexity tests.

It is intended to detect and distinguish SARS-CoV-2, influenza A, influenza B and respiratory syncytial virus (RSV) in a single test.

The FDA noted that the false-positive results may be linked to the present mixing parameters of the polymerase chain reaction (PCR) reaction mixture. This may cause possible overflow carrying over into neighbouring wells in the test reagent tray.

Overflow into wells of true negative samples placed near positive samples in the assay tray could lead to false-positive results.

The regulatory agency recommended that clinical laboratory personnel and healthcare providers should consider positive results from tests using these kits to be presumptive.

Furthermore, the FDA advised considering retesting positive patient samples from the last two weeks with another authorised test.

The agency also recommended informing patients who obtained positive results using these kits from June onwards that they could have had a false positive test result.

At present, the FDA is collaborating with Abbott Molecular to rectify the issues with these molecular testing kits.