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Urine Histidine-to-Creatinine Ratio

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

A urine test that compares histidine with creatinine, helping evaluate the body's handling of the amino acid histidine.

Quick summary

["An elevated ratio may suggest that histidine is not being broken down normally."]

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

Key facts at a glance

LOINC
13757-0
Short code
Histidine/Creat Ur
Synonyms
Histidine/Creat 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 histidine relative to creatinine in a urine sample. Creatinine is used as a reference because its amount can vary with urine concentration.

Why might I need this test?

It may be used to help screen for or investigate histidinemia, an inherited condition in which the body has difficulty processing histidine. It may also be part of an evaluation of unusual amino acid levels or metabolic symptoms.

How is the test performed?

A urine sample is tested in a laboratory to determine the amounts of histidine and creatinine. The results are combined into a histidine-to-creatinine ratio.

How do I prepare for the test?

Follow the collection instructions provided by your healthcare professional or laboratory. The amount of urine collected and the collection time may vary depending on the test request.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated urine histidine-to-creatinine ratio may indicate reduced breakdown or increased excretion of histidine, as can occur with histidinemia. The result should be interpreted with symptoms, diet, other laboratory tests, and the laboratory's reference interval because urine values can vary.

Short name

Urine Histidine/Creatinine Ratio

Frequently asked questions

What does an elevated histidine-to-creatinine ratio mean?
It may suggest that histidine is being excreted in larger amounts relative to creatinine. This can occur with inherited disorders of histidine metabolism, but other results and clinical findings are needed to confirm a diagnosis.
Is this the same as a serum histidine test?
No. This test measures the ratio of histidine to creatinine in urine, whereas a serum histidine test measures histidine concentration in blood.
Can diet affect the result?
Yes. Eating a large amount of protein or histidine-rich foods can increase histidine in urine. Your healthcare professional may advise on dietary preparation if the test is being used for metabolic evaluation.
  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