Glucose (Serum or Plasma) by High-Performance Liquid Chromatography (HPLC)
This test measures the amount of glucose, a type of sugar, in your blood serum or plasma. Glucose is the body’s primary energy source.
["Your blood sugar levels help manage energy and prevent complications like diabetes."]
Key facts at a glance
- LOINC
- 40042-4
- Short code
- Glucose 30H p chal SerPl-mCnc
- Synonyms
- Glucose 30H p chal 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
Your doctor may order this test to help diagnose a medical condition, to check how well an organ or body system is working, or to screen for health problems before symptoms appear. The results give your care team important information that helps guide your treatment plan and follow-up care.
Doctors may order this test to check for high or low blood sugar, monitor diabetes, evaluate symptoms like excessive thirst or fatigue, or assess conditions like hypoglycemia or hyperglycemia.
During the test, a trained member of your care team will explain each step before it happens and answer any questions you have. Depending on the type of test, it may take only a few minutes or a little longer. You may feel some mild discomfort, but most people find the procedure easy to tolerate, and you can usually return to your normal activities soon afterward.
A blood sample is taken from a vein, usually in your arm. You may feel a slight pinch, but it’s quick and painless. The sample is sent to a lab for analysis using HPLC to measure glucose concentration accurately.
This test is often done to look into symptoms such as pain, fatigue, or unusual changes in your body, to monitor an ongoing condition, or to see how well a treatment is working. It may also be part of a routine checkup or required before surgery so your doctor can make informed decisions about your care.
Common reasons include diagnosing diabetes, checking for prediabetes, monitoring blood sugar levels in people with diabetes, or evaluating symptoms like unexplained weight loss, frequent infections, or blurred vision.
Certain things can influence how accurate your results are, including recent meals, medications and supplements, alcohol or caffeine, dehydration, physical activity, and stress. Tell your doctor about everything you take and follow any preparation instructions carefully so your results are as reliable as possible.
Factors like recent meals, exercise, stress, certain medications (e.g., insulin or oral diabetes medications), illness, or dehydration can influence blood glucose levels. Avoid eating or drinking anything except water for a specified period before testing if instructed.
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
Glucose Level
Frequently asked questions
High glucose levels may indicate diabetes, prediabetes, or other metabolic disorders. Consistently low levels can cause dizziness, confusion, or weakness. Regular monitoring helps prevent long-term complications like nerve damage, kidney disease, or heart problems.
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the findings with you during your follow-up visit.
Follow your healthcare provider’s instructions. For fasting tests, avoid food and liquids (except water) for 8–12 hours before the draw. Non-fasting tests may allow light snacks, but confirm with your provider.
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