Aside from clinical presentation, laboratory data may provide essential clues for a differential diagnosis. Elevated WBC and CRP are regarded as indicators for infection or inflammation.18 Our results demonstrated a higher WBC count and CRP level among those with infectious diseases, and a predominance of polymorphonuclear granulocytes and a lower hemoglobin level in those with autoimmune disorders and malignancies. Furthermore, a high WBC count (>20 × 109/mm3) was noted in the patients with malignancies and KD. Platelet count was also addressed in our study because it is regarded as an acute phase reactant, and it was found to be significantly lower in the patients with autoimmune disorders and malignancies. In other words, thrombocytopenia may raise the awareness of the illness in these categories.