[Procalcitonin in pediatric emergencies: comparison with C-reactive protein, interleukin-6 and interferon alpha in the differentiation between bacterial and viral infections].

OBJECTIVE

Procalcitonin concentration increases in bacterial infections but remains low in viral infections and inflammatory diseases. The change is rapid and the molecule is stable making it a potentially useful marker for distinguishing between bacterial and viral infections.

PATIENTS AND

METHODS

Procalcitonin (PCT) was determined with an immunoluminometric assay on plasma collected at admission in 436 infants and children hospitalized for bacterial or viral infection. It was compared with C reactive protein, interleukin-6 and interferon-alpha measured on the same sample.

RESULTS

PCT was 41.3 +/- 77.4 micrograms/l in children with septicemia or bacterial meningitis (n = 53), 0.39 +/- 0.57 microgram/l in children with viral infection (n = 274) and 3.9 +/- 5.9 micrograms/l in children with a localized bacterial infection who had a negative blood culture (n = 109). PCT was > 1 microgram/l in 126 children with a localized or systemic bacterial infection (sensitivity 78%). PCT was < 1 microgram/l in 258 children with a viral infection (specificity 94%). For differenciation between viral and bacterial infections, CRP value > or = 20 mg/l, IL-6 > 100 pg/ml and interferon-alpha > 0 Ul/ml have 85, 48 and 76% sensitivity and 73, 85 and 92% specificity respectively.

CONCLUSIONS

In this study, a PCT value of 1 microgram/l or greater had better specificity, sensitivity and predictive value than CRP, IL-6 and interferon-alpha in children for distinguishing between viral and bacterial infections. PCT may be useful in pediatric emergency room for making decision about antibiotic treatments.