Trottestam et al. found hyperbilirubinemia, methemoglobinemia, and cerebrospinal fluid pleocytosis associated with early death in 232 children with HLH (20); Bin Q et al. found that neutrophils <0.5 × 109/L, total bilirubin over the two-fold upper limit of standard value, and albumin ≤20 g/L at diagnosis were independent risk factors for 30-day mortality in 116 pediatric HLH patients (57); Shaar RA et al. found that changes in ferritin levels are the most significant prognostic factor of 30-day mortality in 123 adult HLH patients (58). Here, ALB is linked to methemoglobinemia.