Mean platelet volume as a marker of Kawasaki disease in children

Background: Kawasaki disease (KD) is a clinical diagnosis, with common confusion among other causes of febrile illnesses. There are no confirmatory laboratory parameters for diagnosing KD. Objective: To investigate whether low mean platelet volume (MPV) is associated more with fever due to KD than due to the other common causes. Methods: This retrospective case-control study was done on febrile children between 6 months and 6 years of age admitted from January 2015 to January 2017. The MPV values of 28 KD and 50 non-KD febrile children admitted to our hospital were obtained from the hospital records. The diagnosis of KD was accepted only when (1) two pediatricians had agreed upon the diagnosis independently based on the American Heart Association guidelines 2004, (2) no other cause of fever coexisted with KD in a particular patient, and (3) prompt clinical response within 48 h of administration of intravenous immunoglobulin. Using suitable statistical software, the range of MPV in KD fever and non-KD fevers was compared. Results: MPV was lower in the KD group (9.75±0.98 femtoliter) than in the non-KD fever group (11.14±1.53 femtoliter). From the receiver operating characteristic curve, it was found that at MPV ≤10.0 fl, KD can be diagnosed with 75% sensitivity and 80% specificity. This means that lower the value of MPV, lower is the probability that a non-KD patientwill be wrongly diagnosed as KD. Conclusion: Our study shows that low MPV is associated with KD. Hence, a low MPV can raise the index of suspicion for KD in febrile children, especially in cases of incomplete KD. Further, prospective studies involving larger sample size are needed to ascertain its diagnostic utility