Urine Methyl Histamine (UMH)

Immunology

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Description

Histamine is widely distributed in mast cells present in tissue and in circulating basophils. It acts on smooth muscle facilitating vasodilation and movement of phagocytic cells to the point of action during the inflammatory response [1]. 1-Methylhistamine (or N-methylhistamine) is a histamine metabolite that is excreted through the kidneys. Urinary 1-methylhistamine (N-methylhistamine) is highly correlated with histamine in plasma. Histamine has a short half life (approximately 1 minute), whereas methylhistamine is a stable end product and is therefore an easier component to quantitate [1]. Histamine is released by mast cells and basophils during allergic reactions and in mast cell activation disorders such as mastocytosis. Therefore, these conditions can be investigated by determination of methylhistamine in urine [1, 2, 3]. In mastocytosis or mast cell activation syndromes an increase in serum tryptase level can be considered a better marker of disease. However in active disease raised urine histamine metabolites can provide additional evidence of disease [2].

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Indications

Anaphylaxis, urticaria, mastocytosis.

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Sample Type

5mL urine, no preservative. Spontaneous urine sample following allergic reaction followed by a baseline sample taken 24 hours post reaction. 24 hour urine sample if investigating MCAS. Requests from outside Sheffield: Freeze sample prior to dispatch and transport frozen sample at ambient temperature via Royal Mail or Courier (dry ice not required).

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Reference Range

<25 ug/mmol creatinine.

Reference range validated in house.

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Turnaround Time

Within 2 weeks

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Testing Frequency

As requested

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External Notes

Sample should be frozen prior to sending via Royal Mail.

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References

PRU Handbook of Clinical Immunochemistry 5th Edition. 1996. [Ref 1].
Valent P. Mast cell activation syndromes: definition and classification. Allergy. 2013. 68(4):417-424. [Ref 2].
Stephan V, et al. Determination of N-methylhistamine in urine as an indicator of histamine release in immediate allergic reactions. J Allergy Clin Imm. 1990. 86(6):862-868. [Ref 3].
Afrin LB. Presentation, diagnosis and management of mast cell activation syndrome. Mast cells. 2013. Chapter 6, pp 155-231. [Ref 4]
Akin C, Valent P and Metcalf D. Mast cell activation syndrome: Proposed diagnostic criteria: Towards a global classification for mast cell disorders. J Allergy Clin Immunol. 2010. 126(6): 1099-1111. [Ref 5].
Valent P, Akin C, Escribano L, et al. Standards and standardisation in mastocytosis: Consensus statements on dignostics, treatment recommendations and response criteria. Euro J Clinn Invest. 2007. 37: 435-453. [Ref 6].

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See Also

Tryptase
Specific IgE

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