Glucose, Serum or Plasma (Quantitative)
This test measures the amount of glucose (sugar) in your blood, typically drawn from a vein or fingerstick. Glucose is the primary energy source for your body.
["Your blood sugar levels help determine how your body uses food for energy and how well your pancreas produces insulin."]
Key facts at a glance
- LOINC
- 9378-1
- Short code
- Glucose 5.5h p 100 g Glc PO SerPl-mCnc
- Synonyms
- Glucose 5.5h p 100 g Glc PO 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 This Test Is Done
Doctors order glucose tests to check for conditions like diabetes, monitor blood sugar levels during treatment, or assess how your body responds to certain foods or medications. It may also be used to evaluate metabolic health or diagnose symptoms such as excessive thirst, fatigue, or unexplained weight changes.
What to Expect Before the Test
For a blood draw, you may have an IV inserted or a small needle used on your arm or finger. If fasting is required, avoid eating or drinking (except water) for a specified period before the test. If urine is involved, you may be asked to collect a sample in a clean container.
What to Expect During the Test
The test is quick and usually painless. A healthcare provider will clean the skin, insert a needle, and collect a small amount of blood. If a fingerstick is used, you may feel a slight pinch. The process typically takes a few minutes.
What to Expect After the Test
After the blood is drawn, the needle or site will be bandaged. You may experience mild bruising, swelling, or discomfort, which usually fades quickly. Avoid vigorous activity at the site for a short time. If you had a urine sample, follow any specific instructions provided to avoid contamination.
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.
High glucose levels may indicate diabetes or other metabolic disorders, while low levels could signal hypoglycemia (low blood sugar), liver disease, or adrenal insufficiency. Regular monitoring helps manage conditions like diabetes and prevents complications such as nerve damage, kidney issues, or cardiovascular problems.
Short name
Glucose Level
Frequently asked questions
How often should I get this test?
What does a normal range mean for me?
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