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Serum Insulin (Quantitative)

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

This test measures the amount of insulin, a hormone produced by your pancreas, in your blood. It helps assess how well your body regulates blood sugar levels.

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
58217-1
Short code
INSULIN
Synonyms
—
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
Method
cms-assessment
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 Is This Test Done?

Your doctor may order this test to check for diabetes, evaluate symptoms like unexplained weight changes, fatigue, or frequent urination, or monitor treatment for conditions affecting blood sugar. It can also help diagnose conditions like hypoglycemia (low blood sugar) or insulin resistance.

What Does the Test Involve?

A blood sample is taken from a vein, usually in your arm. You may feel a small pinch, but it usually doesn’t cause discomfort. The sample is sent to a lab for analysis using an immunoassay method to detect insulin levels.

What to Expect Before the Test

No special preparation is needed for this test. However, if you’re taking medications that affect blood sugar, like insulin or oral diabetes medications, inform your healthcare provider before the test.

What to Expect After the Test

You can resume your normal activities immediately. There may be a small bruise or redness at the site where the blood was drawn, but this usually fades within a few days.

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.

◆Associated findings1

Short name

Insulin Level

Frequently asked questions

How long does it take to get the results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your doctor will discuss the findings with you during your follow-up visit.
Can fasting affect insulin test results?
Yes, fasting (not eating or drinking for 8–12 hours before the test) can influence insulin levels. If your doctor has instructed you to fast, follow their instructions carefully. Non-fasting results may still be useful for diagnosis but should be interpreted by a healthcare provider.
Is there anything I should avoid before the test?
Avoid excessive alcohol, strenuous exercise, or significant changes in your diet 24 hours before the test. If you have questions about medications, let your doctor know—some may temporarily affect blood sugar levels.
  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