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Cystatin C, Serum Concentration (Quantitative)

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

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

Quick summary

["Cystatin C is a simple blood test to check how well your kidneys are working."]

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

Key facts at a glance

LOINC
49351-0
Short code
CMV DNA # Tiss NAA+probe
Synonyms
CMV DNA # Tiss NAA+probe
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 monitor kidney health, especially if you have diabetes, high blood pressure, or a family history of kidney problems. It can also be used to check for kidney disease in people with other health conditions or during pregnancy.

How Is the Test Performed?

A small blood sample is taken from a vein, usually in your arm. The blood is sent to a lab where it is analyzed to measure cystatin C levels.

What Do the Results Mean?

Results are compared to a general reference range, but individual ranges can vary. Higher levels may indicate kidney problems, while lower levels might suggest other conditions. Your doctor will interpret the results in the context of your overall health.

Common Reasons for Testing

This test is often used alongside other kidney function tests, such as creatinine, to get a more complete picture of kidney health. It can also help track kidney function over time if you have a chronic condition.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cystatin C

Frequently asked questions

What causes cystatin C levels to change?
Cystatin C levels can be influenced by factors like age, certain medications, and underlying health conditions. If you are on medications that affect kidney function or have conditions like infections or inflammation, these could also impact your results.
How long does it take to get the results?
Results from this test are typically available within a few days to a week, depending on your lab and healthcare provider’s workflow. Your doctor will discuss the results with you during your follow-up visit.
Can I eat or drink before this test?
You can eat and drink normally before this test, as it does not require fasting. However, always follow your healthcare provider’s specific instructions for your appointment.
  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