Clinical question: What is the relationship between procalcitonin (ProCT) levels and radiographic abnormalities in patients with suspected pneumonia?
Background: Pneumonia is a common clinical diagnosis and reason for admission to the hospital. In a number of cases, however, chest X-rays might not conclusively show an infiltrate. The correlation between ProCT levels and X-ray findings has not been well studied.
Study design: Prospective cohort study.
Setting: Tertiary-care U.S. hospital.
Synopsis: In all, 528 patients with acute respiratory illness were enrolled in the study. Both a blinded radiologist and a pulmonologist involved in the care of each patient reviewed the chest films independently. The pulmonologist was more likely to judge that an infiltrate was present. ProCT levels correlated well with the diagnosis of pneumonia and the presence of an infiltrate by chest X-ray. For patients with an indeterminant film, as determined by the radiologist, ProCT levels were higher in those patients in whom the pulmonologist judged an infiltrate was indeed present. Nearly every patient with an indeterminant film received antibiotics.
One limitation of the study was the lack of a clear gold standard for the determination of a pneumonia diagnosis. And as an observational study, it is uncertain what the effect might be of withholding antibiotics from patients with an indeterminant film and low ProCT levels.
Bottom line: Serum procalcitonin levels correlate well with the presence of an infiltrate by chest X-ray and might have a future role for determining whether patients with indeterminant films can be safely treated without antimicrobials.
Citation: Walsh EE, Swinburne AJ, Becker KL, et al. Can serum procalcitonin levels help interpret indeterminate chest radiographs in patients hospitalized with acute respiratory illness? J Hosp Med. 2012. doi:10.1002/jhm.1984 [Epub ahead of print].