Procalcitonin in diagnosis of severe infections

Area of Science:

• Clinical Medicine
• Biochemistry
• Infectious Diseases

Background:

• Previous studies noted elevated serum procalcitonin (PCT) in pediatric patients with severe bacterial infections.
• The Systemic Inflammatory Response Syndrome (SIRS) criteria are commonly used to identify patients with potential infections.

Purpose of the Study:

• To evaluate the utility of serum procalcitonin (PCT) as a biomarker for diagnosing severe bacterial infections in hospitalized adult patients.
• To determine optimal PCT cut-off values for predicting infection in this population.

Main Methods:

• A prospective study involving 337 hospitalized adult patients meeting SIRS criteria.
• Serum PCT levels were measured on admission and daily for up to 9 days.
• Statistical analysis was performed to calculate validity criteria (sensitivity, specificity, predictive values) for different PCT breakpoints.

Main Results:

• Patients with microbiologically confirmed infections showed peak PCT levels of 30 ng/ml by day 3, with rapid normalization.
• Patients without sepsis had baseline PCT values of 0.1 ng/ml or lower.
• A PCT interval of 0.1-0.5 ng/ml indicated a low likelihood of severe infection (91% sensitivity, 86% negative predictive value).
• PCT levels above 0.5 ng/ml suggested a high likelihood of infection (79% specificity, 61% positive predictive value).

Conclusions:

• Serum PCT is a valuable biomarker in managing infectious diseases in adults.
• A PCT cut-off of 0.5 ng/ml demonstrates excellent specificity and negative predictive value, aiding in ruling out severe infections.
• PCT levels between 0.1 and 0.5 ng/ml require further investigation to confirm or exclude infection.