Serum Glucose (Fasting) with High-Performance Liquid Chromatography (HPLC) Method
This test measures the amount of glucose (sugar) in your blood after you’ve fasted for a set period, often overnight. It helps assess how well your body uses glucose for energy.
["A fasting glucose test is key to checking for diabetes or other metabolic conditions."]
Key facts at a glance
- LOINC
- 25666-9
- Short code
- Glucose 2.5h p Glc SerPl-sCnc
- Synonyms
- Glucose 2.5h 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 Matters
Fasting glucose levels can reveal whether your body processes sugar efficiently. High levels may indicate diabetes or prediabetes, while consistently low levels could signal other health concerns like hypoglycemia or hormonal imbalances.
What to Expect Before the Test
You’ll need to fast (not eat or drink anything except water) for typically 8–12 hours before this test. Your provider will guide you on timing. Bring any medications you take daily, as some may affect results.
How the Test Works
A blood sample is taken from a vein, usually in your arm. The sample is processed to measure glucose concentration using HPLC, a precise method that separates and detects glucose molecules.
What the Results Mean
Results are compared to general reference ranges, but your doctor will interpret them in the context of your overall health. Abnormal results may prompt further testing or lifestyle changes.
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.
Clinical Significance: Fasting glucose is a critical marker for diabetes diagnosis and management. Elevated levels may signal insulin resistance, while persistently low levels could indicate conditions like adrenal insufficiency or severe hypoglycemia. Regular monitoring helps prevent long-term complications like nerve damage or heart disease.
Short name
Fasting Serum Glucose (HPLC)
Frequently asked questions
How long does fasting typically last before this test?
Can I take my usual medications before the test?
What if I have diabetes and my glucose is borderline?
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