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Insulin, Quantitative (Serum/Plasma)

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 much sugar your body uses for energy."]

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

Key facts at a glance

LOINC
55391-7
Short code
Insulin 4M p chal SerPl-sCnc
Synonyms
Insulin 4M p chal SerPl-sCnc
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 doctor may order this test to check for conditions like diabetes, insulin resistance, or to monitor treatment for blood sugar issues. It can also help diagnose problems with your pancreas or adrenal glands.

What Does the Test Involve?

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.

What Do Results Mean?

Results can help determine if your body produces enough insulin or if there’s an imbalance in blood sugar. Abnormal levels may indicate diabetes, hypoglycemia, or other metabolic disorders.

What Are Common Causes?

Conditions like diabetes, pancreatic disorders, or certain medications can affect insulin levels. Stress, diet, or illness may also influence results.

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

What if my insulin level is too high or too low?
High insulin levels might need further evaluation to rule out conditions like insulinoma or Cushing’s syndrome. Low levels could signal diabetes, adrenal insufficiency, or other metabolic issues requiring medical attention.
How often should I get this test?
Frequency depends on your health status. Your doctor will determine how often based on your symptoms, medical history, and treatment plan.
Does fasting affect insulin test results?
Yes, fasting (not eating for 8–12 hours) before the test can provide more accurate results, as insulin levels naturally rise after eating.
  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