Plasma Creatinine-to-Cystatin C Ratio (24-Hour Urine Collection)
This test measures the ratio of creatinine and cystatin C in your urine over 24 hours. It helps assess kidney function by comparing two different markers of muscle breakdown and kidney filtration.
["This ratio helps evaluate kidney health beyond standard blood tests alone."]
Key facts at a glance
- LOINC
- 43667-5
- Short code
- NM Kidney+ves Views W Tc99mDTPA IV
- Synonyms
- NM Kidney+ves Views W Tc99mDTPA IV
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- nm
- 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 Is Used
Your doctor may order this test if they suspect kidney disease, especially if blood tests alone aren’t giving clear results. It can also help monitor kidney function in people with chronic conditions like diabetes or hypertension.
How the Test Works
You’ll collect all urine for a full 24-hour period, typically starting after urinating at midnight. The urine is then sent to the lab for analysis. Creatinine and cystatin C levels are measured separately, and their ratio is calculated.
What to Expect Before the Test
No special preparation is needed beyond following your usual diet and activity level. Drink plenty of water unless instructed otherwise, but avoid excessive fluids that could dilute the urine.
What to Expect During the Test
You’ll collect urine in a container for 24 hours, changing it every time you urinate. A healthcare provider may give you instructions on how to properly collect the sample to ensure accuracy.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test provides a more nuanced view of kidney function compared to blood creatinine alone. Cystatin C is a protein produced by cells, and its levels can reflect kidney function even when blood creatinine is normal. A higher ratio may indicate impaired kidney function, while a lower ratio might suggest overestimation of kidney health by blood tests alone.
Short name
Creatinine:Cystatin C Ratio (Urine)
Frequently asked questions
How long will it take to get my results?
What do my results mean?
Can I eat or drink anything before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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