The primary application of urinary N-methylhistamine (NMH) testing is in the diagnosis and monitoring of mast-cell disorders, including mastocytosis, anaphylaxis, and other severe systemic allergic reactions.
The reference range for urinary NMH varies according to subject age, as follows:
Age 0-5 years – 120-510 µg/g creatinine
Age 6-16 years – 70-330 µg/g creatinine
Older than16 years – 30-200 µg/g creatinine