BACKGROUND: A procalcitonin (PCT) level is commonly ordered to distinguish between bacterial and viral etiologies of lower respiratory tract infections as it is typically negative in the absence of inflammatory conditions and bacterial infections. With COVID-19 causing an influx of patients presenting with respiratory symptoms, clinicians are in need of useful tools to guide management of these patients. Given the inflammation that is caused by COVID-19, it is currently unknown whether PCT continues to be a reliable or useful test in suspected and confirmed cases of COVID-19 pneumonia.
OBJECTIVE: To determine whether PCT remains a clinically useful test in patients who present with lower respiratory tract symptoms in the era of COVID-19.
DESIGN: Single-center retrospective cohort study
PARTICIPANTS: 243 adults with lower respiratory tract symptoms who presented to the hospital through the emergency department between April 11, 2020 and May 18, 2020 who received both a COVID-19 test as well as a PCT level.
MAIN MEASURES: COVID-19 positivity/negative, PCT level
KEY RESULTS: It was found that patients with COVID-19 consistently had negative procalcitonin levels (<0.25ng/mL). Based on the odds ratio, a patient with a positive PCT level was 3.4 times more likely to test negative for COVID than a patient with a PCT level <0.25ng/mL.
CONCLUSIONS: There is a highly significant association between a negative procalcitonin and positive COVID-19 infection, thus supporting the continued use of PCT in the COVID-19 era.