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Histamine/Creatinine Ratio, 24-Hour Urine

Published: August 9, 2026Updated: August 16, 2026

Measures histamine relative to creatinine in urine collected over 24 hours, accounting for urine concentration and daily urine output.

Quick summary

["This test can help evaluate increased histamine release, but an abnormal result must be interpreted with symptoms and other tests."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
13756-2
Short code
Histamine/Creat 24h Ur
Synonyms
Histamine/Creat 24h Ur
Category
kidney
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

This test measures histamine, a chemical involved in inflammation and allergic reactions, in all urine collected over 24 hours. The histamine result is compared with the amount of creatinine in the same urine sample.

Why might I need this test?

It may be used to help evaluate unexplained flushing, hives, swelling, abdominal symptoms, wheezing, or other symptoms that may be related to histamine release. It is sometimes considered when a mast-cell disorder is suspected, but it cannot confirm that diagnosis by itself.

How is the test performed?

You collect all urine for 24 hours in a special container provided by the laboratory. The urine volume and collection time are recorded, and a laboratory sample is analyzed for histamine and creatinine. The creatinine comparison helps account for differences in urine concentration.

How do I prepare for the test?

Follow the laboratory's collection instructions carefully, including when to start and how to store the container. Tell the laboratory about medicines, supplements, unusual foods, alcohol use, or a recent illness, because these may affect interpretation. Do not change your diet or stop prescribed medicines unless your clinician instructs you to do so.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Urine Histamine

Frequently asked questions

Why is creatinine included in the result?
Creatinine is used to account for how concentrated the urine is. Comparing histamine with creatinine makes the measurement less dependent on variations in urine concentration.
Does an abnormal result diagnose a mast-cell disorder?
No. Urinary histamine can support an evaluation, but it is not specific enough to diagnose a mast-cell disorder on its own.
What if I miss part of the 24-hour urine collection?
Tell the laboratory, because an incomplete collection can make the result unreliable. The laboratory may advise repeating the collection or may document the collection time when interpreting the result.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy