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Insulin, Serum Concentration

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

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

Quick summary

["Insulin levels help diagnose and monitor conditions like diabetes and insulin resistance."]

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

Key facts at a glance

LOINC
8072-1
Short code
Insulin Ab Ser-aCnc
Synonyms
Insulin Ab Ser-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 Is This Test Done?

Your healthcare provider may order a serum insulin test to check for conditions affecting blood sugar control, such as diabetes, hypoglycemia (low blood sugar), or insulin-producing tumors. It may also be used in research or specialized evaluations, like assessing insulin sensitivity or pancreatic function.

When Might You Need This Test?

You might need this test if you have symptoms like unexplained weight changes, frequent urination, extreme thirst, fatigue, or if you have a family history of diabetes or other metabolic disorders. It could also be part of a broader evaluation for unexplained low blood sugar or hormonal imbalances.

What to Expect Before the Test

No special preparation is usually 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 fasting isn’t required, avoid heavy meals or caffeine before the blood draw.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. The blood sample is sent to a lab for analysis. The test measures insulin concentration in your serum, which is the liquid part of blood without blood cells.

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

Serum Insulin

Frequently asked questions

What does a high serum insulin level mean?
A high serum insulin level may signal conditions like insulinoma (a tumor producing extra insulin), insulin resistance, or reactive hypoglycemia (a temporary drop in blood sugar after eating). Your provider will consider your symptoms and other test results to interpret results accurately.
What does a low serum insulin level mean?
Low serum insulin levels can occur with diabetes (especially type 1), certain medications, starvation, or severe illness. It may also be part of a broader evaluation if you have unexplained low blood sugar or hormonal imbalances.
Can diet or fasting affect insulin test results?
Yes, fasting for 8–12 hours before the test can help provide more accurate results, especially if it’s part of a glucose-insulin study. If fasting isn’t required, avoid heavy meals or caffeine, as they may temporarily alter insulin 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