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Insulin concentration in serum (20-hour postprandial)

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

This test measures the amount of insulin in your blood after you’ve eaten a meal, specifically 20 hours later. It helps assess how your body responds to glucose after eating.

Quick summary

["This test helps evaluate insulin production and glucose metabolism over time."]

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

Key facts at a glance

LOINC
47661-4
Short code
Insulin 20M p Glc SerPl-aCnc
Synonyms
Insulin 20M p Glc SerPl-aCnc
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
2.6
Ref high
24.9
Fasting
true
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 This Test Is Done

Your healthcare provider may order this test if you have symptoms of diabetes, insulin resistance, or other metabolic conditions. It can also be used to monitor how well your body processes glucose after meals, especially in people with suspected delayed insulin release or abnormal glucose tolerance.

What to Expect Before the Test

You’ll typically fast for 12–14 hours before the test, but the 20-hour measurement is taken after you’ve eaten a standard meal. Follow your provider’s instructions precisely to ensure accurate results.

How the Test Is Performed

A blood sample is drawn from a vein (usually in your arm) by a healthcare professional. The sample is sent to a lab for measurement of insulin levels in your serum.

What the Results Mean

Results are interpreted by your provider based on your medical history, symptoms, and other test results. Abnormally high or low levels may signal issues with insulin production, glucose metabolism, or other metabolic disorders.

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 (20-hour post-meal)

Frequently asked questions

What does a high insulin level mean?
High insulin levels after a meal may indicate insulin resistance, hyperinsulinemia, or conditions like Cushing’s syndrome or certain tumors that produce excess insulin. It could also reflect how your body handles glucose postprandially.
What does a low insulin level mean?
Low insulin levels after a meal may suggest diabetes (insufficient insulin production), pancreatic issues, or other metabolic disorders affecting glucose regulation.
How often should I get this test?
Your provider will determine the frequency based on your health needs, symptoms, and treatment plan. Regular monitoring may be recommended if you have diabetes, prediabetes, or related conditions.
  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