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Free Sialate-to-Creatinine Ratio, Serum

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

A specialized blood test that compares free sialic acid (sialate) with creatinine to help evaluate sialic acid metabolism.

Quick summary

["This ratio may help identify abnormalities in sialic acid metabolism when interpreted with other clinical and laboratory findings."]

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

Key facts at a glance

LOINC
104658-0
Short code
Sialate.free/Creat Ur-sRto
Synonyms
Sialate.free/Creat Ur-sRto
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?

The free sialate-to-creatinine ratio compares the amount of free sialic acid, also called sialate, with the amount of creatinine in serum. Creatinine is used as a reference measurement when evaluating the relative amount of sialate.

Why might I need this test?

This specialized test may be ordered when a clinician is evaluating a suspected disorder of sialic acid metabolism, particularly in the setting of unusual developmental, neurologic, or metabolic findings. It is usually interpreted as part of a broader metabolic evaluation.

How is the test performed?

A blood sample is collected, and the serum is analyzed to measure free sialate and creatinine. The laboratory then calculates the ratio between the two measurements.

How do I prepare for the test?

Follow the preparation instructions provided by your healthcare professional. Fasting is generally not required for this test, but the laboratory or ordering clinician may have specific instructions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Free sialate/creatinine ratio

Frequently asked questions

What does the free sialate-to-creatinine ratio measure?
It compares free sialic acid with creatinine in serum. The ratio provides context because creatinine is commonly used as a reference measurement.
Is this the same as a routine creatinine test?
No. A routine creatinine test measures creatinine alone, while this test also determines free sialate and calculates their relationship.
What if the result is abnormal?
An abnormal result may prompt additional testing or review by a metabolic specialist. Your healthcare professional will interpret it with your symptoms, medical history, and other laboratory 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