Glucose in Serum or Plasma (2-Hour Postprandial)
This test measures your blood sugar level two hours after eating. It helps assess how your body processes glucose, which is important for managing blood sugar control.
["This test helps doctors check how well your body handles glucose after eating."]
Key facts at a glance
- LOINC
- 50608-9
- Short code
- GTT gest 3h Pnl SerPl
- Synonyms
- GTT gest 3h Pnl SerPl
- Category
- glucose
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 80
- Ref high
- 200
- Critical range
- 20 N/A – 400 N/A
- Fasting
- true
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84436
- SNOMED
- 302346007
- 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?
Your healthcare provider may order this test if you have symptoms of high blood sugar, such as frequent urination, excessive thirst, or unexplained weight changes. It may also be used to monitor conditions like diabetes or to evaluate how certain medications affect blood sugar levels.
What to Expect Before the Test
You’ll typically fast for 8 to 12 hours before the test, unless instructed otherwise. Bring your fasting status confirmation to your appointment. Blood is drawn from a vein in your arm, usually in a clinic or lab setting. The process is quick and usually painless.
What the Results Mean
Results are compared to standard reference ranges, but your specific values will be discussed with your healthcare provider. High levels may indicate diabetes or insulin resistance, while consistently low levels could signal hypoglycemia or other metabolic issues.
Common Conditions Monitored
This test is critical for diagnosing and managing diabetes, prediabetes, and other metabolic disorders. It can also help evaluate the effectiveness of treatments like insulin or oral medications.
Reference range
Adult: 80-200 ng/dLN/A
Take your thyroid medication after the blood draw if applicable. No fasting required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test plays a key role in identifying glucose metabolism disorders. Elevated or low levels can signal underlying health conditions that require medical attention, such as diabetes, hypoglycemia, or hormonal imbalances. Regular monitoring helps prevent complications and guides treatment decisions.
Frequently asked questions
What does a 2-hour postprandial glucose test measure?
Do I need to fast for this test?
Can I eat or drink anything 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 17, 2026. · Read our editorial policy