mast-cell-activation-syndrome-diagnosis-consensus-2-criteria

Mast Cell Activation Syndrome (MCAS): diagnosis consensus-2 criteria

Source. Diagnosis established upon demonstration of the major criterion combined with at least one minor criterion (and absence of any other disease better accounting for the problems).

Major Criterion:

1. Constellation of clinical complaints attributable to pathologically increased MC activity (MC mediator release syndrome)

Minor Criteria:

1. Multifocal or disseminated infiltrates of MCs in marrow and/or extracutaneous organ(s) (e.g., gastrointestinal or genitourinary tract; >19 MCs/high power field)

2. Abnormal spindle-shaped morphology in >25% of MCs in marrow or other extracutaneous organ(S)

3. Abnormal MC expression of CD2 and/or CD25 (i.e., co-expression of CD117/CD25 or CD117/CD2)

4. MC genetic changes (e.g., activating KIT codon 419, 509 or 560 mutations) shown to increase MC activity

5. Evidence (typically from body fluids such as whole blood, serum, plasma, or urine) of above-normal levels of MC mediators including: tryptase, histamine or its metabolites (e.g., N-methylhistamine), heparin, chromogranin A (note potential confounders of cardiac or renal failure, neuroendocrine tumors, recent proton pump inhibitor use, or chronic atrophic gastritis), other relatively MC-specific mediators (e.g., ecosanoids including prostaglandin (PG) D2, its metabolite 11-B-PGF2a, or leukotriene E4)

6. Symptomatic response to inhibitors of MC activation or MC mediator production or action.