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Cystatin C Protein, Serum/Plasma (Quantitative)

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

This test measures the concentration of cystatin C, a protein produced by nearly all cells in the body. It helps assess kidney function.

Quick summary

["Cystatin C is a simple blood test that helps monitor kidney health."]

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

Key facts at a glance

LOINC
72493-0
Short code
CMV DNA SerPl NAA+probe-aCnc
Synonyms
CMV DNA SerPl NAA+probe-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to evaluate kidney function, especially if you have symptoms like swelling, fatigue, or changes in urine output. It can also be used to monitor kidney disease progression or guide treatment decisions, particularly in patients with diabetes or high blood pressure.

How Is the Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure cystatin C levels using a specialized immunoassay or similar method.

What Are Common Results?

Results are typically reported as a concentration value (in mg/dL or similar units). Higher than expected levels may indicate reduced kidney function, while lower levels may suggest other conditions.

What Does It Mean If My Results Are Abnormal?

Abnormal results may signal kidney problems, including chronic kidney disease. Your provider will discuss findings in the context of your medical history and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Cystatin C is a more reliable marker than traditional creatinine tests for assessing kidney function, especially in patients with muscle mass variations or certain genetic conditions. It is often used alongside creatinine to provide a more comprehensive picture of kidney health, particularly in chronic kidney disease monitoring.

Short name

Cystatin C

Frequently asked questions

How long does it take to get my results?
Results are usually available within 1–3 business days, depending on your lab and healthcare provider’s workflow.
What if my results are outside the normal range?
If your results are abnormal, your healthcare provider will review them with you and may recommend further testing, adjustments to medications, or lifestyle changes to address potential kidney concerns.
Can I eat or drink before this test?
You may eat and drink normally before this test, as it does not require fasting. However, always follow your provider’s 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