False-positive Xpert® Xpress SARS-CoV-2 assay in an emergency room and trauma center: A retrospective chart review study.

OBJECTIVES

To review reports false-positive Xpert results in an emergency room and trauma center.

METHODS

Patients' data with false-positive Xpert results from November 2020 to February 2022 at Pusan National University Hospital, Busan, Republic of Korea, were extracted from the electronic medical records.

RESULTS

The positive predictive value of Xpert was 40%. Of the 12 patients with false-positive results, 5 (41.7%) were re-positives (such as, patients recovered from coronavirus disease-19 [COVID-19]), and 4 (33.3%) had head or facial trauma. Two out of 4 head or facial trauma cases had documented sample contamination with blood.

CONCLUSION

We found a high incidence of false-positive Xpert results among patients who recovered from COVID-19 and those with head or facial injury. Careful history taking for COVID-19 and physical examination of the sample collection site is essential before Xpert analysis.