Serum Creatinine to Urea Ratio (C:U Ratio) – 24-Hour Urine Collection
This test measures the balance between creatinine and urea in your urine over 24 hours to help assess kidney function and fluid balance.
["Helps evaluate kidney health and fluid retention by comparing waste products in urine."]
Key facts at a glance
- LOINC
- 101571-8
- Short code
- CAGKDNA
- Synonyms
- C glabrata+krusei DNA Vag Ql NAA+probe
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, leak-proof container or nucleic acid transport medium (NAT) tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- female
- Age range
- 12–99 years
- Method
- probe-amp-tar
- CPT
- 87481
- SNOMED
- 122450008
- Specimen volume
- 1-2 mL of vaginal fluid
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Your doctor may order this test if you have symptoms like swelling, high blood pressure, or signs of kidney problems. It can also help diagnose conditions like kidney disease, heart failure, or fluid overload. This test is particularly useful when other kidney function tests (like blood creatinine) alone may not provide enough information.
What to Expect Before the Test
You’ll need to collect all urine for 24 hours, starting after midnight on one day and ending midnight the next. Drink plenty of water to help your kidneys produce urine, but avoid excessive diuretics or medications that affect urine output. Follow your doctor’s instructions carefully to ensure accurate results.
How the Test Is Done
You’ll use a special container to collect every drop of urine for 24 hours. Store the urine in a refrigerator until you return it to the lab. The lab will then analyze the urine for both creatinine and urea levels.
What the Results Mean
A higher ratio may suggest kidney problems, fluid overload, or conditions like heart failure. A lower ratio could indicate dehydration or certain metabolic conditions. Your doctor will interpret results in the context of your overall health and symptoms.
Reference range
Negative for Candida glabrata and Candida krusei DNA. Positive results indicate the presence of Candida glabrata and/or Candida krusei DNA in the specimen.N/A
Patient should avoid douching, vaginal medications, and sexual intercourse for 24-48 hours prior to specimen collection. Ideally, specimen should be collected prior to initiation of antifungal therapy for accurate detection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Creatinine-to-Urea Ratio (24-hour urine)
Frequently asked questions
What does a high creatinine-to-urea ratio indicate?
What does a low creatinine-to-urea ratio indicate?
How often should this test be repeated?
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