The aims of this study were to compare serum procalcitonin (PCT) levels between febrile children with Kawasaki disease (KD) and those with bacterial or viral infections, and assess the clinical usefulness of PCT level in predicting KD.

Serum PCT levels were examined in febrile pediatric patients admitted between August 2013 and August 2014. The patients were divided into 3 groups as follows: 49 with KD, 111 with viral infections, and 24 with bacterial infections.

The mean PCT level in the KD group was significantly lower than that in the bacterial infection group (0.82±1.73 ng/mL vs. 3.11±6.10 ng/mL, P =0.002) and insignificantly different from that in the viral infection group (0.23±0.34 ng/mL, P =0.457). The mean erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level in the KD group were significantly higher than those in the viral and bacterial infection groups ( P <0.001 and P <0.001 for ESR, P <0.001 and P =0.005 for CRP, respectively). The proportion of patients in the KD group with PCT levels of >1.0 ng/mL was significantly higher in the nonresponders to the initial intravenous immunoglobulin treatment than in the responders (36% vs. 8%, P =0.01).

PCT levels may help to differentiate KD from bacterial infections. A combination of disease markers, including ESR, CRP, and PCT, may be useful for differentiating between KD and viral/bacterial infections.