Table 1. Diagnostic criteria for JMML... | American Society of Hematology

Table 1.

Diagnostic criteria for JMML per the 2016 WHO Classification⁴

Category I: clinical and hematologic features (all 4 features mandatory)	Category II: genetic studies (1 feature is sufficient)	Category III: other features (patients without features of category II must have ≥2 of the following features)
Absence of t(9:22) BCR/ABL fusion gene	Somatic mutation in KRAS, NRAS, or PTPN11*	Circulating myeloid or erythroid precursors
Absolute monocyte count > 1000/µL	Clinical diagnosis of NF-1 or NF1 gene mutation	Monosomy 7 or other chromosomal abnormality
Less than 20% blasts in peripheral blood/bone marrow	Germline CBL mutation or LOH of CBL	WBC > 10 000/μL
Splenomegaly		Increased hemoglobin F for age
		GM-CSF hypersensitivity^†
		Hyperphosphorylation of STAT5^†

Category I: clinical and hematologic features (all 4 features mandatory)	Category II: genetic studies (1 feature is sufficient)	Category III: other features (patients without features of category II must have ≥2 of the following features)
Absence of t(9:22) BCR/ABL fusion gene	Somatic mutation in KRAS, NRAS, or PTPN11*	Circulating myeloid or erythroid precursors
Absolute monocyte count > 1000/µL	Clinical diagnosis of NF-1 or NF1 gene mutation	Monosomy 7 or other chromosomal abnormality
Less than 20% blasts in peripheral blood/bone marrow	Germline CBL mutation or LOH of CBL	WBC > 10 000/μL
Splenomegaly		Increased hemoglobin F for age
		GM-CSF hypersensitivity^†
		Hyperphosphorylation of STAT5^†

Germline mutations need to be excluded.

These tests are not routinely available and are rarely used to make a clinical diagnosis of JMML.