Serum/plasma concentration of glucose (fasting or non-fasting)
This test measures the amount of glucose (sugar) in your blood, either after fasting (no food for 8+ hours) or at a random time. It helps doctors check for diabetes, blood sugar control, or other metabolic conditions.
["Glucose levels help diagnose and monitor diabetes and other blood sugar-related health issues."]
Key facts at a glance
- LOINC
- 73550-6
- Short code
- Acarbose ind plt IgM SerPl Ql FC
- Synonyms
- Acarbose ind plt IgM SerPl Ql FC
- Category
- hematology
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- flow-cytometry
- CPT
- 82784
- 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 a glucose test to diagnose conditions like diabetes, check how well diabetes treatments are working, or evaluate symptoms such as excessive thirst, fatigue, or unexplained weight changes. It may also be used during pregnancy (gestational diabetes) or before certain surgeries.
Fasting vs. Random Glucose Testing
If fasting glucose is requested, you’ll need to avoid eating or drinking (except water) for 8 hours before the test. If it’s a random glucose test, you can eat normally, but results may vary more. Fasting tests are often used to confirm diabetes diagnosis, while random tests can detect high blood sugar during symptoms.
What to Expect During the Test
A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it usually doesn’t cause pain. The blood sample is sent to a lab for analysis. Most tests take less than 10 minutes.
Possible Results and Next Steps
Results may be reported as either a fasting glucose level or a random glucose level. If your results are outside the expected range, your doctor may recommend further testing, such as an oral glucose tolerance test (OGTT) or hemoglobin A1c (HbA1c) to better understand your blood sugar status.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Glucose Level
Frequently asked questions
High glucose levels (hyperglycemia) can indicate diabetes, prediabetes, or other metabolic disorders. Persistently low glucose levels (hypoglycemia) may signal insulin-related issues or other health problems. Regular monitoring helps prevent long-term complications like nerve damage, kidney disease, or heart problems.
A normal glucose level (whether fasting or random) does not mean your blood sugar is always perfectly balanced. It simply indicates that your immediate blood sugar is within a typical range. For long-term management, tests like HbA1c provide a clearer picture of average blood sugar over months.
No, you must avoid all food and liquids (except water) for 8 hours before a fasting glucose test. If you have questions about timing, ask your doctor or lab technician.
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