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Urine Histamine/Creatinine Ratio

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

A urine test that measures histamine relative to creatinine to help evaluate mast-cell activation and certain suspected mast-cell disorders.

Quick summary

["An elevated result may support increased mast-cell activity but must be interpreted with symptoms, history, and other testing."]

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

Key facts at a glance

LOINC
110527-9
Short code
Histamine/Creat Msmt Ur
Synonyms
Histamine/Creat Msmt 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 substance released by mast cells, in urine. Urine creatinine is measured at the same time and used to calculate the ratio, which helps account for differences in urine concentration.

Why might I need this test?

It may be ordered when a clinician is evaluating recurring flushing, hives, abdominal symptoms, fainting, or other features of a possible mast-cell disorder. It may also be used when an allergic or non-allergic reaction is suspected to involve mast-cell activation.

How is the test performed?

A urine sample is tested for histamine and creatinine, and the laboratory calculates the histamine-to-creatinine ratio. Depending on the laboratory's instructions, this may use a spot urine sample or urine collected over 24 hours.

How do I prepare for the test?

Follow the collection instructions provided by the laboratory, including collecting all urine for the full period if a 24-hour collection is requested. Tell your clinician about recent allergic reactions, symptoms, and medicines or supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Histamine/Creatinine Ratio

Frequently asked questions

Does an elevated result mean I have systemic mastocytosis?
No. An elevated result indicates that more histamine was released relative to creatinine, but it does not establish a specific diagnosis. Your clinician will consider your symptoms and other testing.
Why is creatinine included in this test?
Creatinine is used to adjust the histamine measurement for how concentrated the urine is. This makes results easier to compare between samples.
Do I need to fast or avoid medicines before this test?
Special preparation is usually not required, but collection timing can affect the result. Do not stop prescribed medicines without speaking with your clinician; tell the laboratory about relevant medicines, supplements, and recent reactions.
  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