Serum procalcitonin levels and empirical antibiotic treatment of patients with community-acquired febrile syndromes

Procalcitonin and pneumonia: is it a useful marker?

An ideal biomarker for pneumonia should allow an early diagnosis and differential diagnosis from noninfectious conditions and should inform about the course and prognosis of the disease. Procalcitonin (PCT) covers these features better as compared to more commonly used biomarkers like C-reactive protein or leukocyte count. PCT complements and improves the assessment of pneumonia based on careful patient history, dedicated physical examination, and appropriate cultures. Importantly, a PCT-based therapeutic strategy can safely and markedly reduce antibiotic courses in community-acquired pneumonia. However, as is the cast with all diagnostic surrogate markers, PCT can be increased in noninfectious conditions and may remain low in bacterial infections, especially localized infections. This stresses the importance of follow-up measurements, because PCT levels in these patients often show a gradual increase during follow-up. Although PCT is -better than more common biomarkers for the prognosis of pneumonia and to predict survival and outcome, novel biomarkers show an even better prognostic accuracy.

The potential role of procalcitonin in the emergency department management of febrile young adults during a sustained meningococcal epidemic

OBJECTIVE

To prospectively investigate the diagnostic characteristics of procalcitonin as an aid in the diagnosis of meningococcal disease in febrile young adults presenting to the Waikato Hospital emergency department during a sustained meningococcal epidemic.

METHODS

The study population were emergency department patients aged 14-40 years presenting with either a temperature > or = 38.0 degrees C without an obvious focus of infection, or symptoms consistent with meningococcal disease. All had procalcitonin levels, N. meningitidis PCR, blood +/- CSF cultures.

RESULTS

One hundred and eighty-three patients presented with undifferentiated febrile illness over a 9 month study period. Nine were subsequently shown to have meningococcal disease. A positive procalcitonin (> or = 0.5 ng/mL) had a sensitivity of 100% (CI 66.4-100), specificity 89% (CI 83.1-93.1), negative predictive value 100% (CI 97.6-100) and positive predictive value 32% (CI 15.9-52.4) for meningococcal disease.

CONCLUSIONS

The finding of a procalcitonin level > or = 0.5 ng/mL in young adults with undifferentiated fever indicates an increased chance that the presenting illness may be meningococcal disease. In New Zealand's continuing meningococcal epidemic empirical antibiotics should be strongly considered in those with elevated procalcitonin levels in the hope of reducing meningococcal disease deaths due to delays in antibiotic administration.