Test Directory

Screening for and monitoring of mastocytosis and disorders of systemic mast-cell activation, such as anaphylaxis and other forms of severe systemic allergic reactions using random urine specimens

Monitoring therapeutic progress in conditions that are associated with secondary, localized, low-grade persistent, mast-cell proliferation and activation such as interstitial cystitis

Specimen Type: Random Urine

Collection Container: Plastic Urine Container (Preservative Free) 

Desired Specimen Volume: 5 mL

1. Collect random urine in a plastic urine container (preservative free).
2. Collect within a few hours of symptom onset.

1. Transfer a minimum of 3 mL of urine to a clear aliquot tube (screw top).

Transport to the laboratory refrigerated. 

See patient report.

While an average North American diet has no effect on urinary N-methylhistamine (NMH) levels, mild elevations (around 30%) may be observed on very histamine-rich diets. This problem is more pronounced if random-urine specimens are used and collected following a histamine-rich meal.

NMH levels may be depressed in individuals who have an alteration in the histamine-N-methyltransferase gene (HNMT), which encodes the enzyme that catalyzes NMH formation. This alteration results in an amino acid change that decreases the rate of NMH synthesis.

When N-acetylcysteine is administered at levels sufficient to act as an antidote for the treatment of acetaminophen overdose, it may lead to falsely decreased creatinine results.

• 1-Methylhistamine
• Histamine Metabolites
• Urinary N-Methylhistamine
• NMHR
• NMH
• N-Methylhistamine