Table 2.

2006 classification criteria of MAS.

A febrile patient with known or suspected systemic juvenile idiopathic arthritis is classified as having macrophage activation syndrome if the following criteria are met:

Ferritin > 684 ng/ml and any two of the following:

Platelet count ≤ 181 × 109/liter

Aspartate aminotransferase > 48 units/liter

Triglycerides > 156 mg/dl

Fibrinogen ≤ 360 mg/dl

Adapted from Ravelli et al. (2015, 2016).