The US Food and Drug Administration (FDA) has warned users not to use Cue Health’s at-home Covid-19 tests, just one week after the agency issued a warning letter saying that Cue was not following the conditions specified in the emergency use authorisations for its tests. 

The FDA warning said that the tests could give false results, specifically saying that the company had changed how the electrochemical signals within the test device were generated, received, and interpreted. These changes were not authorised by the FDA and may decrease the stability of the tests and lead to false results, according to the agency. 

Based in San Diego, Cue Health has suffered since the pandemic, as the demand for Covid-19 tests has dwindled. Its workforce continues to be slashed, with 714 layoffs across January and April 2023, 245 in January 2024, and 230 this month. The company went public in 2021 at a valuation of nearly $2.3bn. However, it lost $194.1m and $373.5m in 2022 and 2023 respectively, as per the company’s financials. 

The Cue Health Covid-19 test for home and over-the-counter use was authorised by the FDA for point-of-care testing in June 2020, receiving an emergency use authorisation (EUA) in March 2021 for at-home use. Cue secured $481m in a deal with the US Government in October 2020 to ramp up production of the tests, which were said to be used by the NBA to screen players. 

The nucleic acid amplification test (NAAT) diagnoses the disease by analysing a lower nasal swab sample taken using the single-use Cue Sample Wand, which is run through the reusable Cue Cartridge Reader. It then delivers the results to its smartphone app. 

The FDA said Cue Health has 15 days to address "specific steps your firm has taken to address the noted violations, as well as an explanation of how your firm plans to prevent these violations, or similar violations, from occurring again", in the 9 May warning letter. 

The agency recommended that users retest using a different FDA-approved Covid-19 test. Last week, iHealth Lab’s Covid-19/Flu A&B won FDA EUA for individuals aged two and above. Intended to deliver results in 15 minutes, the 3-in-1 test kit is said to be one of the first over-the-counter rapid antigen tests for both Covid-19 and influenzas A and B in the US.