Kawasaki disease (KD) is the primary cause of heart disease among children, but because its clinical symptoms are nonspecific, it is difficult to diagnose. The purpose of this study was to evaluate laboratory indices for possible use in the early diagnosis of KD and to determine which indices are predictive of a response to intravenous immunoglobulin (IVIG) and can be used to monitor the effects of treatment.

Three hundred thirty KD patients, 330 age‐matched children with KD‐like febrile disease, and 330 age‐matched healthy children (controls) were enrolled in this prospective study. Levels of N‐terminal pro–brain natriuretic peptide (NT‐proBNP), erythrocyte sedimentation rate (ESR), C‐reactive protein (CRP), and cytokines were determined in all study subjects.

In the derivation cohort, 181 patients in the KD group were compared with 181 patients in the KD‐like febrile group. The following indices were found to be useful in the diagnosis of KD: NT‐proBNP (area under the curve [AUC] 0.923), ESR (AUC 0.909), CRP (AUC 0.834), and interleukin‐6 (IL‐6; AUC 0.678). The diagnostic efficiency of each index demonstrated in the derivation cohort was repeated in the 149 KD patients in the validation cohort. There were significant differences in NT‐proBNP levels between IVIG‐responsive KD patients (n = 270) and IVIG‐nonresponsive KD patients (n = 60), with higher NT‐proBNP levels in IVIG‐nonresponsive KD patients. The NT‐proBNP level can effectively distinguish IVIG‐responsive KD patients from IVIG‐nonresponsive patients, and its AUC was 0.73. There were also significant differences in the NT‐proBNP levels before and after treatment, with a significant decline after treatment.

Serum levels of NT‐proBNP can be used in the diagnosis of KD, the prediction of a patient's sensitivity to IVIG treatment, and the monitoring of the effects of IVIG treatment, but more attention must be paid to the scope of its application.