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Phosphoserine/Creatinine Ratio, 24-Hour Urine

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

A 24-hour urine test measures phosphoserine relative to creatinine to help evaluate urinary phosphoserine excretion.

Quick summary

["This test measures how much phosphoserine is excreted in urine over 24 hours, relative to creatinine."]

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

Key facts at a glance

LOINC
57013-5
Short code
Phosphoserine/Creat 24h Ur-Rto
Synonyms
Phosphoserine/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?

Phosphoserine is an amino acid used in cellular signaling and enzyme regulation. This test measures the amount of phosphoserine in a 24-hour urine collection and compares it with the amount of creatinine in the same sample.

Why might I need this test?

This test may be ordered to evaluate phosphoserine metabolism or investigate unusual urinary amino acid excretion. It is generally interpreted along with symptoms, other laboratory results, and genetic or metabolic testing when needed.

How is the test performed?

You collect all urine for exactly 24 hours, usually starting in the morning and ending at the same time the following day. The laboratory measures phosphoserine and creatinine and calculates their ratio.

How do I prepare for the test?

Follow the collection instructions provided by your healthcare professional and label the container with the start and end times. Do not change your diet, medications, or fluid intake unless your clinician specifically tells you to do so.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An abnormal ratio may indicate altered phosphoserine production or metabolism, differences in kidney excretion, or an issue with the urine collection. This test is not commonly interpreted on its own, and results should be assessed with your healthcare professional alongside other relevant findings.

Short name

24-Hour Urine Phosphoserine/Creatinine Ratio

Frequently asked questions

Why is creatinine included in this test?
Creatinine is used as a reference measurement to help account for variations in urine concentration. Comparing phosphoserine with creatinine provides a normalized measure of phosphoserine excretion.
How do I collect a 24-hour urine sample?
Collect all urine during a full 24-hour period, including nighttime samples, using the container provided. Record the collection start and end times and return the sample as instructed.
What if I miss part of the urine collection?
Tell your healthcare professional or laboratory, because a missed collection can make the result less reliable. Do not try to estimate the missing amount unless you receive specific instructions.
  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