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Serum or plasma concentration of insulin (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 the pancreas.

Quick summary

["Insulin levels help your body control how much sugar stays in your blood."]

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

Key facts at a glance

LOINC
37855-4
Short code
XR Sinuses 4V
Synonyms
XR Sinuses 4V
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
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 This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of high or low blood sugar, such as excessive thirst, fatigue, or unexplained weight changes. It may also be used to monitor conditions like diabetes, hypoglycemia, or to check for insulin resistance.

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 tolerance or metabolic study. Bring any medications you’re currently taking.

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 the Results Mean

Results are interpreted based on your overall health, symptoms, and medical history. High insulin levels might suggest insulin resistance, tumors, or other endocrine issues, while very low levels could indicate diabetes or other metabolic disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Frequently asked questions

How often should I get this test?
Insulin levels are typically checked as part of a broader metabolic panel or specific condition evaluation (e.g., diabetes screening, hypoglycemia monitoring). Your provider will determine frequency based on your needs.
Can I eat or drink before this test?
If fasting is required, avoid food or liquids (except water) for the specified period. If fasting isn’t needed, follow your provider’s instructions for timing.
What if my insulin levels are abnormal?
Abnormal results may prompt further testing, such as glucose monitoring or additional hormone checks. Your provider will discuss next steps based on your symptoms and lab findings.
  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