Glucose, Serum (Mass Concentration)
This test measures the amount of glucose (sugar) in your blood serum. It helps monitor blood sugar levels, often used in diabetes management or to assess metabolic health.
A simple blood test to check your blood sugar levels.
Key facts at a glance
- LOINC
- 1512-3
- Short code
- Glucose 1M p .5 g/kg Glc IV SerPl-mCnc
- Synonyms
- Glucose 1M p .5 g/kg Glc IV SerPl-mCnc
- 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 Is This Test Done?
This test measures the amount of glucose, or sugar, in your blood. It helps your doctor find out how well your body handles blood sugar and is often used to screen for diabetes, monitor an existing diagnosis, or check for low blood sugar.
Your healthcare provider may order this test to diagnose or monitor conditions like diabetes, prediabetes, or to check for low blood sugar (hypoglycemia). It can also be used during pregnancy, before surgeries, or to evaluate overall metabolic health.
What to Expect Before the Test: Your doctor will tell you whether you need to fast before this test. Fasting usually means nothing to eat or drink except water for 8 to 12 hours. Keep taking your regular medicines unless your doctor gives you other instructions, and let your care team know about any medicines or supplements you use.
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a fasting blood sugar panel. If you’re pregnant or have certain conditions, your provider may give specific instructions.
How the Test Is Performed: A nurse or technician will clean a spot on your arm, usually the inside of your elbow, and place a tight band around your upper arm. A small needle is then used to draw a sample of blood into a tube. You may feel a quick sting, and the whole process takes only a few minutes. Afterward, a small bandage is placed on the site.
A small blood sample is drawn from a vein, usually in your arm, using a needle. The serum portion of the blood is then separated and tested for glucose concentration using an automated laboratory method.
What the Results Mean: A normal result means your blood glucose is within the expected range for your age and health situation. A result that is higher than normal may suggest diabetes or prediabetes, while a result that is lower than normal may point to hypoglycemia. Your doctor will review your numbers along with your symptoms and medical history before deciding on next steps.
Results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). While reference ranges vary by lab, high or low values may signal diabetes, prediabetes, or other metabolic issues. Your provider will interpret results in the context of your overall health.
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
Short name
Serum Glucose
Frequently asked questions
High glucose levels may indicate diabetes, insulin resistance, or other endocrine disorders. Low glucose levels can cause fatigue, dizziness, or confusion. Regular monitoring helps prevent complications like nerve damage, kidney disease, or cardiovascular issues.
If your glucose is consistently high, your doctor may recommend lifestyle changes (like diet and exercise), medications, or further testing. If low, you may need immediate treatment (e.g., glucose tablets or juice) and follow-up with your provider to prevent severe symptoms.
Yes, fasting (not eating/drinking for 8–12 hours) often improves accuracy for glucose tests. If you’re unsure, ask your provider about fasting requirements before the 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