Glucose in Serum (Fasting or Random) with Differential or Fluctuation Analysis
This test measures your blood sugar levels in serum, sometimes including how they vary over time or compared to previous results.
["Blood sugar levels help monitor diabetes and other conditions affecting glucose metabolism."]
Key facts at a glance
- LOINC
- 72650-5
- Short code
- Glucose ser - peric fld-SCDiff
- Synonyms
- Glucose ser - peric fld-SCDiff
- 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 healthcare provider may order this test to check for diabetes, hypoglycemia (low blood sugar), or to monitor blood sugar trends in people with known conditions like prediabetes or insulin resistance. It may also be used to assess how your body responds to treatments or medications.
What to Expect Before the Test
For a fasting glucose test, you’ll typically fast for 8–12 hours before the blood draw. If it’s a random glucose test, no fasting is required. Bring any medications you’re taking and let your provider know if you have any concerns about fasting.
What Happens During the Test
A healthcare professional will draw blood from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause significant discomfort. The blood sample is sent to a lab for analysis.
What the Results Mean
Results may include a single fasting or random glucose value or a comparison of glucose levels at different times (e.g., fasting vs. post-meal). If differential analysis is included, it may show how glucose levels fluctuate over time or between samples.
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
Glucose Profile (Serum)
Frequently asked questions
What does a high or low glucose level indicate?
How often should I get this test?
Can I eat or drink 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