Improper glove hygiene leads to COVID-19 false positives

2022 04 22 19 39 4362 Glove Doctor Patient 400

Improper glove hygiene at COVID-19 testing centers in Belgium caused cross contamination of samples and a high rate of false positives, according to research presented April 23 at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) annual meeting in Lisbon.

In September, scientists at the department of laboratory medicine at UZ Leuven in Leuven, Belgium, noticed that 70% of samples taken on a particular day at a testing center in the Flemish Brabant province of Belgium were positive for COVID-19 (average positive test rate at that time was 5% to 10%).

Researchers found that 90% of these positive samples had a low viral load, which suggested they had been contaminated with the SARS-CoV-2 virus rather than being true positives.

Follow-up inquiry found that a failure to frequently change gloves led to the contamination, according to lead researcher Bram Slechten. Reasons for inappropriate glove-changing practices included:

  • A lack of explicit protocols
  • Protocols in place but not followed due to lack of staff training
  • Not having the right size of glove available
  • The pressure of having to swab many patients quickly

Slechten and colleagues checked four months of results (June to September) from 11 testing centers and found potential false-positive COVID-19 test results due to cross contamination in 73% of the facilities. More rigorous personal protective equipment (PPE) protocols and staff training was implemented in October 2021.

Most cases of cross-contamination-related positive COVID-19 results were identified in time to withhold the results and recall the affected patients for another test, according to the researchers.

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