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. Author manuscript; available in PMC: 2020 Feb 6.
Published in final edited form as: Expert Rev Clin Immunol. 2019 Apr 22;15(6):639–656. doi: 10.1080/1744666X.2019.1596800

Table 7.

Diagnostic Criteria for Systemic Mastocytosis

Major criterion a. Multifocal, dense infiltrates of mast cells (≥15 mast cells in aggregates) detected in intramedullary biopsy sections and/or extramedullary organ(s).
Minor criteria a. In intramedullary biopsy sections or other extramedullary ones >25% of the mast cells in the infiltrate are spindle shaped or have atypical morphology, or of all mast cells in bone marrow aspirate smears >25% are immature or atypical
b. Gain of function point mutation of KIT at codon 816 (usually KIT D816V) in bone marrow, blood, or other extracutaneous organ
c. Aberrant immunophenotype of mast cells of CD2 and/or CD25 in bone marrow, blood, or other extracutaneous organ (in addition to normal mast cell markers)
d. Persistently elevated baseline serum total tryptase (>20 ng/ml).