When we evaluate the qualitative results with the cutoff value of 38.5% for NK-cytotoxicity and 250 pg/mL for NKA-IFNγ, agreement between the two assays was 88.0% in HLH group and 58.0% in non-HLH group (p < 0.001) (Table 3). Here, IFNG is linked to hemophagocytic syndrome.