Adjuvant laboratory marker of Kawasaki disease; NT-pro-BNP or hs-CRP?

The diagnosis of Kawasaki disease (KD) is based on clinical data and non-pathognomonic symptoms. As no specific diagnostic test for KD exists, BNP or NT-pro-BNP might be of importance in identifying KD. We compared serum hs-CRP and NT-pro-BNP level in the acute phase of 59 KD patients and evaluated the diagnostic performance of these laboratory markers in KD to estimate the cut-off level for differentiating KD from other febrile illnesses as age-matched controls.

The study groups consisted of 59 KD patients in the disease group and 45 other patients with febrile illnesses as age-matched controls. NT-pro-BNP was measured using Elecsys proBNP (Roche Diagnostics, Mannheim, Germany), and hs-CRP was tested with CardioPhase hs-CRP (Siemens Healthcare Diagnostics, Marburg, Germany).

NT-pro-BNP levels were significantly higher in the KD patients than in the controls (P < 0.001). In the ROC curve analysis, the sensitivity was 66.10%, and the specificity was 77.08% at 235.2 pg/mL. hs-CRP levels tended to be higher in KD patients compared to controls.

This study indicates that NT-pro-BNP might be a more useful laboratory marker as an adjuvant diagnostic tool for KD than hs-CRP. Especially in a patient with incomplete clinical features of KD, the diagnosis and the start of treatment were delayed to confirm a fever persisting for at least 5 days. Therefore, we expect that NT-pro- BNP would be especially useful for KD patients with these atypical clinical presentations.