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Formate/Creatinine Ratio, Urine

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

Measures the amount of formate relative to creatinine in urine. This toxicology test may help evaluate exposure to methanol or related substances.

Quick summary

["A urine formate-to-creatinine ratio can help assess possible methanol or other toxic alcohol exposure."]

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

Key facts at a glance

LOINC
108385-6
Short code
Formate/Creat Msmt Ur
Synonyms
Formate/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 formate, a breakdown product, relative to creatinine in a urine sample. Creatinine is used to account for differences in urine concentration.

Why might I need this test?

It may be ordered when exposure to methanol or another toxic alcohol is suspected, particularly after symptoms, an ingestion, or workplace exposure. It can also be used to follow certain occupational exposures.

How is the test performed?

A urine specimen is collected and tested in the laboratory. The formate result is compared with the urine creatinine result to calculate the ratio.

How do I prepare for the test?

Follow the collection instructions provided by your healthcare professional. The timing of urine collection may depend on why the test was ordered, so ask whether a first-morning or timed specimen is required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An increased formate-to-creatinine ratio may indicate increased exposure to methanol or substances that produce formate during metabolism. Results can also be affected by recent exposure, urine concentration, liver function, and other metabolic factors, so they should be interpreted alongside symptoms, history, and other laboratory tests.

Short name

Urine Formate/Creatinine Ratio

Frequently asked questions

What is formate?
Formate is a metabolic form of formic acid. It can increase in the body after exposure to methanol, although other substances and metabolic conditions may also affect its level.
Why is creatinine included in this urine test?
Urine can vary greatly in how concentrated it is. Comparing formate with creatinine helps reduce the effect of urine dilution or concentration on the reported ratio.
Does a high result mean someone has methanol poisoning?
Not by itself. A high result may suggest relevant exposure, but diagnosis and interpretation depend on the clinical situation, symptoms, exposure history, and confirmatory testing.
  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