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Insulin, Serum or Plasma Concentration (Quantitative)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of insulin in your blood, which helps your body use sugar (glucose) for energy. Insulin is a hormone produced by your pancreas.

Quick summary

["Insulin levels help diagnose and monitor diabetes and other metabolic conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
27379-7
Short code
Insulin 1h p chal SerPl-aCnc
Synonyms
Insulin 1h p chal SerPl-aCnc
Category
hormone
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
2.6
Ref high
24.9
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83525
SNOMED
413618004
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

Your doctor may order this test to check for diabetes, insulin resistance, or other hormonal imbalances. It can also help evaluate symptoms like unexplained weight changes, fatigue, or unusual thirst/urination. In some cases, it’s used to assess how well insulin therapy is working in people with diabetes.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a glucose-insulin study. If you’re pregnant, breastfeeding, or have certain conditions (like kidney disease), let your doctor know before testing.

How the Test Is Performed

A blood sample is drawn from a vein in your arm, usually by a healthcare professional. The sample is sent to a lab where insulin levels are measured using an immunoassay method (often clia or fia), which detects insulin molecules in your blood.

What the Results Mean

Results are interpreted based on your clinical context, not just a single number. High insulin levels may suggest insulin resistance, hypoglycemia (low blood sugar), or other disorders. Low levels could indicate diabetes, pancreatic issues, or hormonal problems. Your doctor will discuss these findings with you.

Reference range

Fasting: 2.6-24.9 μIU/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Insulin Level

Frequently asked questions

What could cause abnormal insulin levels?
Abnormally high insulin levels might be due to conditions like insulinoma (a rare tumor), Cushing’s syndrome, or certain medications. Low insulin levels could result from diabetes, pancreatic disease, or genetic disorders affecting insulin production. Always correlate results with symptoms and other tests for accurate diagnosis.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you once they’re ready to discuss them.
Can I eat or drink before this test?
If fasting is required (e.g., for a glucose-insulin study), avoid food and liquids except water for 8–12 hours beforehand. If no fasting is needed, you can eat and drink normally. Always follow your doctor’s specific instructions.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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