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Insulin, Serum/Plasma Concentration (Quantitative)

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

This test measures the amount of insulin in your blood, which helps regulate blood sugar levels. Insulin is a hormone produced by your pancreas.

Quick summary

["Insulin helps control how your body uses sugar for energy."]

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

Key facts at a glance

LOINC
56945-9
Short code
Insulin 56h p chal SerPl-aCnc
Synonyms
Insulin 56h 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

What Does This Test Measure?

Insulin is a hormone that helps your body use sugar (glucose) for energy. Your pancreas releases insulin in response to high blood sugar levels. This test checks the concentration of insulin in your blood, typically drawn from serum or plasma.

Why Might You Need This Test?

Doctors may order an insulin test to diagnose or monitor conditions like diabetes, hypoglycemia (low blood sugar), or other metabolic disorders. It can also help evaluate how well your body is responding to insulin therapy.

How Is the Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure insulin levels. The test may be performed as part of a fasting or non-fasting blood draw, depending on the clinical context.

What Are Common Uses?

Insulin tests are commonly used to diagnose diabetes, check for insulin resistance, assess insulin secretion in conditions like hypoglycemia, or evaluate pancreatic function. They may also be used in research or specialized clinical settings.

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.

Abnormally high insulin levels may indicate conditions such as insulinoma (a rare tumor that overproduces insulin) or reactive hypoglycemia. Low insulin levels can suggest diabetes, insulin deficiency, or other metabolic issues. Results help guide treatment plans, such as medication adjustments or lifestyle changes.

Short name

Insulin Level

Frequently asked questions

What Does a Low or High Insulin Level Mean?
Low insulin levels may indicate diabetes, where your body doesn’t produce enough insulin, or other metabolic disorders. High levels might suggest conditions like reactive hypoglycemia or, in rare cases, insulin-producing tumors.
How Often Should I Get This Test?
The frequency depends on your health condition and treatment plan. Your healthcare provider will determine how often you need this test based on your diagnosis and medical needs.
Can I Eat or Drink Before the Test?
If fasting is required, follow your doctor’s instructions. Some tests may be done on non-fasting blood, but this can affect results. Always check with your provider before the test.
  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