From the Guidelines
The Sonora Quest laboratory test that includes N-methylhistamine is the Urine N-Methylhistamine test, which is used to detect and monitor mast cell activation disorders and mastocytosis. This test measures the levels of N-methylhistamine, a metabolite of histamine, in a 24-hour urine collection. The test is particularly valuable because N-methylhistamine is more stable in urine than histamine itself, providing a more reliable indicator of mast cell activity, as noted in the study by 1.
Some key points to consider when preparing for this test include:
- Patients should follow specific collection instructions provided by Sonora Quest, typically involving refrigeration of the specimen during the collection period.
- Certain medications and foods can affect test results, so patients may need to avoid histamine-rich foods, histamine-releasing foods, and antihistamines prior to testing as directed by their healthcare provider.
- This test helps clinicians diagnose conditions involving inappropriate mast cell activation, which can cause symptoms like flushing, itching, gastrointestinal issues, and anaphylaxis, as discussed in the study by 1.
It's also important to note that the diagnosis of mast cell activation syndrome (MCAS) should be entertained in patients with an appropriate clinical and laboratory profile when other conditions have been excluded, as stated in the study by 1. The study by 1 provides additional information on the treatment of MCAS, including the use of antihistamines and other medications to manage symptoms.
Overall, the Urine N-Methylhistamine test is a useful tool for detecting and monitoring mast cell activation disorders and mastocytosis, and can help clinicians diagnose and manage conditions involving inappropriate mast cell activation.
From the Research
Sonora Quest Test Overview
The Sonora Quest test that includes N-methylhistamine is a laboratory test used to measure the levels of N-methylhistamine in a patient's urine.
- N-methylhistamine is a metabolite of histamine, a biogenic amine involved in various physiological processes, including allergic reactions and immune responses.
- The test is used to diagnose and monitor conditions such as mastocytosis, a disorder characterized by an excessive accumulation of mast cells in the body 2, 3.
- Elevated levels of N-methylhistamine in urine may indicate mast cell activation and histamine release, which can be associated with various symptoms, including itching, flushing, and gastrointestinal disturbances 4, 5.
Clinical Applications
The Sonora Quest test that includes N-methylhistamine has several clinical applications, including:
- Diagnosing mastocytosis and monitoring disease activity 2, 3
- Identifying patients with mast cell activation syndrome (MCAS), a condition characterized by episodes of mast cell mediator release 5
- Detecting histamine intolerance, a disorder caused by impaired histamine degradation due to diamine oxidase (DAO) enzyme deficiency 4, 6
- Monitoring the effectiveness of treatments aimed at reducing histamine levels and alleviating symptoms associated with mast cell activation and histamine release.
Test Interpretation
The interpretation of the Sonora Quest test that includes N-methylhistamine requires careful consideration of the patient's clinical presentation and medical history.
- Elevated levels of N-methylhistamine in urine may indicate mast cell activation and histamine release, but may also be influenced by other factors, such as dietary histamine intake and renal function 4, 6.
- The test results should be interpreted in conjunction with other diagnostic tests and clinical evaluations to confirm a diagnosis and develop an effective treatment plan 2, 3, 5.