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Table 1 WHO diagnostic criteria for systemic mastocytosis*

From: The significance of diagnosing associated clonal mast cell diseases in patients with venom-induced anaphylaxis and the role of bone marrow investigation

Major criterion
1. Presence of multifocal, dense mast cell infiltrates (>15 in aggregates) in bone marrow or other extracutaneous organs
Minor criteria
1. >25% mast cells spindle-shaped or with abnormal morphology in bone marrow or other extracutaneous organs.
2. Detection of c-kit point mutation at codon 816 in bone marrow, blood or extracutaneous organs
3. Mast cells that coexpress CD117 with CD2 and/or CD25, in bone marrow or extracutaneous organs
4. Persistent increased serum total tryptase level (>20 ng/ml)
  1. *The diagnosis of systemic mastocytosis (SM) can be established if the major and one minor criterion or three minor criteria are fulfilled (adapted from reference 6). If the patients fulfill only one or two minor criteria (particularly criteria 2 or 3), which not sufficient for SM diagnosis, will be diagnosed as monoclonal mast cell activation syndrome.