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Serum/Plasma Substance Concentration for a Renal Function Marker (e.g., Cystatin C)

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

This test measures the level of a protein called cystatin C in your blood. It helps assess how well your kidneys are working.

Quick summary

["Cystatin C helps monitor kidney function and may be used alongside other tests."]

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

Key facts at a glance

LOINC
53022-0
Short code
U1 snRNP Ab Ser Ql
Synonyms
U1 snRNP Ab Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of kidney problems, such as swelling, fatigue, or changes in urine output. It may also be used to track kidney function in people with diabetes, high blood pressure, or other health conditions that can affect the kidneys.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood. If you’re on blood thinners, let your provider know before the test.

What the Test Results Mean

Higher than expected levels of cystatin C may indicate kidney problems, while lower levels might suggest other conditions. Your results will be compared to a general reference range provided by your lab.

Common Reasons for Testing

Doctors often use cystatin C to check kidney function, especially in people with chronic illnesses like diabetes or heart disease. It can also help determine how well dialysis is working or monitor kidney disease progression.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

None

Frequently asked questions

What causes cystatin C levels to change?
Several factors can influence cystatin C levels, including age, muscle mass, and certain medications. Kidney disease, infections, or dehydration may also temporarily raise levels. If you have questions about your specific results, discuss them with your healthcare provider.
Is this test the same as a creatinine test?
No, cystatin C and creatinine are different tests. Creatinine measures waste from muscle breakdown, while cystatin C measures a protein produced by cells. Both are used together to assess kidney function, but they provide slightly different insights.
How often should I get this test?
Your provider will determine how often you need this test based on your health condition. For example, people with kidney disease may need it more frequently to monitor changes in kidney function over time.
  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