A recent study published in Clinical Chemistry provided interesting information about the superiority of CRP over procalcitonin (PCT) in clinical utility and diagnosis of pneumonia. The study was performed in two phases. First, the aim was to compare the diagnostic accuracy of PCT, IL-6, and CRP in pneumonia with patients who arrived at the emergency department with dyspnea. In the second phase, the randomized management study evaluated the use of PCT in guiding the duration of antibiotic therapy in patients who had acute heart failure and suspected pneumonia. The first diagnostic study found an unexpectedly low clinical utility for PCT. CRP and IL-6 had significantly higher diagnostic accuracy than PCT in the early diagnosis of pneumonia.
The unexpectedly low diagnostic accuracy of PCT led to an earlier stop of the second phase study, where PCT-guided antibiotic treatment shortening was compared to the conventional hospital treatment procedure. The study did not find a significant difference in treatment duration or hospitalization length between the groups and authors stated that due to the insufficient diagnostic accuracy, PCT should not be used to shorten antibiotic treatment.
The guidelines in Europe and the USA differ in their recommendations on how to manage pneumonia. In European guidelines, CRP is often recommended, whereas in the USA, the American Infectious Diseases Society of America/American Thoracic Society guidelines favor PCT. The authors suggested that because the costs for CRP measurement are less than 5% of the PCT costs in most countries, the current guidelines in the USA should be revised and CRP or IL-6 should be considered the choice of a biomarker to support the clinical and radiographic assessment in the diagnosis of pneumonia.
Link to the original article: http://clinchem.aaccjnls.org/content/65/12/1532.long