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Serine-to-Creatinine Ratio, Urine

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

This urine test compares the amount of serine with the amount of creatinine in the same sample. It may be used in evaluating unusual amino-acid metabolism.

Quick summary

["The result helps assess urinary serine relative to creatinine, but it must be interpreted with other clinical and laboratory findings."]

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

Key facts at a glance

LOINC
30058-2
Short code
Serine/Creat Ur-Rto
Synonyms
Serine/Creat 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 serine and creatinine in a urine sample and calculates the ratio of one to the other. Creatinine is used as a reference to help account for differences in urine concentration.

Why might I need this test?

This specialized test may be ordered to evaluate serine metabolism or to monitor a patient with a suspected inherited or acquired amino-acid disorder. It is not a routine general health test.

How is the test performed?

A urine specimen is collected according to your clinician's instructions. The laboratory measures the serine and creatinine concentrations and reports their ratio.

How do I prepare for the test?

Follow the specific collection instructions provided by your clinician, including whether a timed or first-morning sample is needed. Tell your clinician about supplements, medicines, dietary changes, and urine-collection problems that could affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An abnormal ratio may reflect a disorder affecting serine metabolism, changes in kidney function, or differences in urine concentration. The result is not specific to one condition and should be interpreted with symptoms, diet, medications, and other laboratory tests.

Short name

Urine Serine/Creatinine Ratio

Frequently asked questions

What does the urine serine-to-creatinine ratio show?
It shows the amount of serine in urine relative to the amount of creatinine. Creatinine helps adjust for how concentrated or dilute the urine sample is.
Is this test used for routine kidney screening?
No. It is a specialized test more often associated with evaluating amino-acid metabolism, although your clinician may use it in other specific situations.
Do I need to collect urine for 24 hours?
That depends on your clinician's instructions. Some tests can use a single urine sample, while others require a timed collection, so follow the directions provided with the test order.
  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