Serum Glucose (Fasting) with Serum Creatinine Ratio
This test measures your blood glucose level and compares it to your creatinine level in your serum. It helps assess how well your kidneys filter glucose and may be used to evaluate kidney function or glucose metabolism together.
["A ratio helps identify potential kidney or metabolic issues by linking blood sugar and kidney function in one test."]
Key facts at a glance
- LOINC
- 25663-6
- Short code
- Glucose 15M p Glc SerPl-sCnc
- Synonyms
- Glucose 15M p Glc SerPl-sCnc
- Category
- glucose
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 70
- Ref high
- 100
- Critical range
- 50 N/A – 400 N/A
- Fasting
- true
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82947
- SNOMED
- 260395008
- 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 Done
Your doctor may order this test if you have symptoms like frequent urination, excessive thirst, or unexplained weight changes. It could also be part of a routine checkup, especially if you have risk factors for diabetes or kidney problems. Some tests combine glucose and kidney function to simplify monitoring.
What to Expect Before the Test
You’ll need to fast for 8–12 hours before this test, meaning no food or drink (except water) for that time. Avoid smoking or chewing gum. Bring your fasting blood sample to the lab for analysis.
How the Test Works
A healthcare provider will draw blood from a vein in your arm. The blood sample is sent to a lab where glucose and creatinine levels are measured separately. The results are then compared to calculate the ratio.
What the Results Mean
While individual results vary, doctors often interpret ratios in the context of your overall health. High ratios may suggest kidney issues or diabetes, while low ratios could indicate other conditions like severe dehydration or liver disease. Your doctor will discuss these findings with you.
Reference range
Fasting: 70-100 mg/dLN/A
Fasting for 8-12 hours required. Water is permitted. Avoid chewing gum and smoking before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Fasting Glucose/Creatinine Ratio
Frequently asked questions
What does a fasting glucose test combined with creatinine ratio tell me about my health?
Why do doctors sometimes use a ratio instead of separate glucose and creatinine tests?
Can fasting affect the accuracy of 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