Insulin Level — 8-Hour Timed Measurement
A timed insulin blood test used to assess insulin levels and how the body responds to food, fasting, or administered insulin.
["The result is best interpreted with the collection timing, recent meals, and insulin doses because all can affect the insulin level."]
Key facts at a glance
- LOINC
- 89908-8
- Short code
- Insulin taken in last 8H 8h
- Synonyms
- Insulin taken in last 8H 8h
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84484
- SNOMED
- 302774002
- 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
What is this test?
This test measures the amount of insulin in a blood sample. Insulin is a hormone that helps glucose move into cells for energy and helps regulate blood glucose. The test code includes 8-hour timing, so the exact timing of the sample is important.
Why might I need this test?
Clinicians may order a timed insulin test when evaluating hypoglycemia, suspected insulin resistance, or how the body responds to a meal or glucose load. It may also be used in the care of diabetes, metabolic conditions, or symptoms related to excess insulin.
How is the test performed?
A blood sample is collected and sent to a laboratory, where insulin is measured with a laboratory assay. The result may be interpreted alone or alongside a simultaneous glucose measurement and other tests.
How do I prepare for the test?
Follow the timing instructions provided by your clinician, including whether you should fast and when the blood should be drawn. Do not skip meals, exercise excessively, or change insulin or other medicines unless your clinician instructs you to do so. Record the timing of your last meal and any insulin dose.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An insulin level that is unexpectedly high or low can reflect fasting, recent food intake, physical activity, or the use of insulin or other medicines. Patterns of elevated insulin may occur with insulin resistance, while unexpectedly low insulin can contribute to hypoglycemia. A single result cannot establish a diagnosis and should be interpreted with glucose levels, symptoms, medication use, and the collection timing.
Short name
Insulin (8-hour timing)
Frequently asked questions
Does the 8-hour timing mean I must fast for 8 hours?
Can I take my usual insulin before this test?
What other information helps interpret the result?
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