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Homocysteine-to-Creatinine Ratio, 24-Hour Urine

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

Measures homocysteine relative to creatinine in urine collected for 24 hours. The ratio helps account for differences in urine concentration.

Quick summary

["This test measures urinary homocysteine and may help evaluate vitamin B12, folate, and related metabolic concerns."]

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

Key facts at a glance

LOINC
56682-8
Short code
(Hcys)2/Creat 24h Ur-Rto
Synonyms
(Hcys)2/Creat 24h Ur-Rto
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 the amount of homocysteine in your urine relative to the amount of creatinine. Creatinine is used as a reference because it adjusts for how concentrated or dilute your urine is.

Why might I need this test?

A 24-hour urine homocysteine test may be used along with other tests to evaluate homocysteine metabolism. Your clinician may order it when investigating low vitamin B12 or folate levels, kidney-related concerns, or a possible inherited metabolic condition.

How is the test performed?

You collect all urine produced during a full 24-hour period in a special container. The laboratory measures homocysteine and creatinine and calculates their ratio.

How do I prepare for the test?

Follow your clinician's collection instructions carefully, including the exact start and end times. Keep the container refrigerated if instructed, record any missed urine, and return the sample promptly. Fasting is generally not required unless your clinician says otherwise.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Urine Homocysteine/Creatinine Ratio

Frequently asked questions

Why is creatinine included in this test?
Creatinine helps adjust the homocysteine measurement for variations in urine concentration. This makes the ratio more useful than an unadjusted urine measurement.
How is a 24-hour urine sample collected?
Usually, you empty your bladder at the start time and collect every subsequent urine sample for 24 hours. The final sample is collected at the end time, and the container is labeled with both times and returned as directed.
Does an abnormal result mean I have a vitamin deficiency?
Not necessarily. Elevated homocysteine can have several causes, so your clinician will interpret it together with vitamin B12, folate, kidney function, and other test results.
  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