Determination of plasma heparin level improves identification of systemic mast cell activation disease.

Diagnosis of mast cell activation disease (MCAD), i.e. systemic mastocytosis (SM) and idiopathic systemic mast cell activation syndrome (MCAS), usually requires demonstration of increased mast cell (MC) mediator release. Since only a few MC mediators are currently established as biomarkers of MCAD, the sensitivity of plasma heparin level (pHL) as an indicator of increased MC activation was compared with that of serum tryptase, chromogranin A and urinary N-methylhistamine levels in 257 MCAD patients. Basal pHL had a sensitivity of 41% in MCAS patients and 27% in SM patients. Non-pharmacologic stimulation of MC degranulation by obstruction of venous flow for 10 minutes increased the sensitivity of pHL in MCAS patients to 59% and in SM patients to 47%. In MCAS patients tryptase, chromogranin A, and N-methylhistamine levels exhibited low sensitivities (10%, 12%, and 22%, respectively), whereas sensitivities for SM were higher (73%, 63%, and 43%, respectively). Taken together, these data suggest pHL appears more sensitive than the other mediators for detecting systemic MC activity in patients with MCAS. The simple, brief venous occlusion test appears to be a useful indicator of the presence of pathologically irritable MCs, at least in the obstructed compartment of the body

Sensitivities of heparin, tryptase, chromogranin A levels in blood and <i>N</i>-methylhistamine excretion into urine for indication of an increased mast cell activity.

<p>Sensitivities of heparin, tryptase, chromogranin A levels in blood and <i>N</i>-methylhistamine excretion into urine for indication of an increased mast cell activity.</p

Characteristics of the study population.

<p>Characteristics of the study population.</p

Mast cell mediators or their metabolites in blood or urine which currently can be determined as routine laboratory parameters.

<p>Mast cell mediators or their metabolites in blood or urine which currently can be determined as routine laboratory parameters.</p

Percentage of the study population fulfilling the criteria proposed to define <i>systemic mastocytosis</i> (for references, see text) when all other diagnoses that could better explain the full range and chronicity of the findings in the case have been excluded.

<p>Percentage of the study population fulfilling the criteria proposed to define <i>systemic mastocytosis</i> (for references, see text) when all other diagnoses that could better explain the full range and chronicity of the findings in the case have been excluded.</p