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Serum Insulin Concentration (Quantitative)

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 sensitivity."]

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

Key facts at a glance

LOINC
43740-0
Short code
Glucose/Insulin SerPl
Synonyms
Glucose/Insulin SerPl
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
70
Ref high
100
Critical range
50 N/A – 400 N/A
Fasting
true
Population
adult
Sex
all
Age range
18–65 years
CPT
82947
SNOMED
260395008
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 this test if you have symptoms of low blood sugar (hypoglycemia), high blood sugar (hyperglycemia), or if you have a history of diabetes or other metabolic disorders. It may also be used to evaluate insulin resistance or to check for conditions like insulinoma, a rare tumor that produces excess insulin.

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 profile. If you’re pregnant, breastfeeding, or have certain medications, let your provider know. Avoid smoking or caffeine before the test if advised.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause significant discomfort. The blood sample is sent to a lab for analysis.

What Do the Results Mean?

Results are interpreted by your healthcare provider based on your medical history and symptoms. Very low or very high levels may indicate underlying health concerns, but individual results vary. Your provider will explain what your specific results mean for you.

Reference range

Fasting: 70-100 mg/dLN/A

Specimen: serum

Fasting for 8-12 hours required. Water is permitted. Avoid chewing gum and smoking before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Serum Insulin

Frequently asked questions

What Does This Test Measure?
This test measures the concentration of insulin in your blood serum. Insulin helps regulate blood sugar by allowing cells to absorb glucose. Abnormal levels can signal diabetes, insulin-related disorders, or other metabolic issues.
How Is This Test Used in Diagnosis?
Insulin levels are often checked alongside glucose tests (e.g., fasting glucose) to diagnose conditions like reactive hypoglycemia, insulinoma, or insulin resistance. It may also help monitor treatment effectiveness for diabetes.
What Are Common Causes of Abnormal Results?
Abnormally low insulin levels may occur due to pancreatic issues (e.g., pancreatitis, diabetes), certain medications, or severe illness. Abnormally high levels could indicate insulinoma, Cushing’s syndrome, or pseudohypoglycemia. Always discuss results with your provider.
  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