The Particulars: Procalcitonin (PCT) testing helps guide antibiotic therapy by indicating whether a patient has a viral or bacterial infection. PCT levels will rise only in response to bacterial infections, not viral infections. The performance of PCT testing in a real-world setting without formal provider education is not well understood.

Data Breakdown: An analysis of 402 PCT tests found negative results in 32.6% of cases. Antibiotics were discontinued for 46.8% of patients in the study. Among those with negative PCT findings, 50.6% had a documented infection in their chart, suggesting a 49.4% negative predictive valued of the PCT test. This occurred despite an 88.3% positive predictive value. No differences were observed in mortality, readmission, or length of hospital or ICU stays between patients with negative PCT tests whose antibiotics were continued and those whose antibiotics were de-escalated or discontinued. The authors noted that a treatment algorithm and accompanying education may allow for appropriate use of PCT testing.

Take Home Pearls: Provider education and the use of treatment algorithms appear to be necessary to allow for proper interpretation of PCT testing.