Test Overview
Test Methodology


Test Usage

Documentation of immediate hypersensitivity reactions or diagnosis of patients with systemic mastocytosis. Elevated values are seen in patients with anaphylaxis, with urticaria, or following provocative skin tests.

Reference Range *

0.006 - 0.131 mg/24 hour

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

False negatives may occur if collection of the specimen is not performed near the time of allergic reactions.

Test Details
Days Set Up
Tuesday, Friday
Analytic Time

4 - 11 days

Soft Order Code
MiChart Code
Histamine, 24 HR Urine
  • HST-24
  • HST24
  • Histamine, 24-Hour Urine
Reference Laboratory
Mayo FHI24 (Quest 4946X)
Special Testing
Specimen Requirements

Collect 24 hour urine specimen. Add 30 mL of 6 N HCl (10 mL for pediatric patients) to container prior to start of collection. Following collection, mix well, measure 24 hour urine volume, aliquot 4 mL into a plastic urine container and refrigerate. Record total 24 hour urine volume and collection dates/times on request form. Specimens with no preservative are also acceptable: add HCl to container following collection, mix well and send 4 mL aliquot (preferred); alternatively a non-acidified aliquot will be accepted. Patient should void antihistamines, oral corticosteroids, and substances that block H2 receptors for at least 24 hours prior to specimen collection.

Normal Volume
4 mL aliquot of 24 hour urine collection
Minimum Volume
2 mL aliquot of 24 hour urine collection
Additional Information

Test sent to Mayo Medical Laboratories; performed by Quest Nichols Institute.

CPT Code
Fee Code