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Human Insulin-Specific IgE, Serum/Plasma — Radioallergosorbent Test (RAST)

Published: August 9, 2026Updated: August 17, 2026

Detects IgE antibodies against human insulin in blood. It helps evaluate suspected immediate insulin allergy but does not measure insulin or glucose levels.

Quick summary

["A positive result may indicate an immune reaction to human insulin, but symptoms and timing must be considered for confirmation."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
102388-6
Short code
Insulin Human IgE RAST
Synonyms
Insulin Human IgE RAST
Category
hormone
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rast
CPT
84484
SNOMED
302774002
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

What is this test?

This blood test detects IgE antibodies directed against human insulin. It is used when an immediate allergic reaction to insulin is suspected, rather than to measure the amount of insulin in the blood.

Why might I need this test?

Your clinician may order this test if you developed hives, swelling, wheezing, dizziness, or other sudden symptoms after an insulin injection. It may also be considered when insulin is needed but a prior reaction makes treatment choices unclear.

How is the test performed?

A blood sample is collected and analyzed in a laboratory for insulin-specific IgE antibodies. The RAST name refers to a laboratory method historically used to measure allergen-specific IgE.

How do I prepare for the test?

No special preparation is usually required, and you should not stop insulin unless your clinician instructs you to do so. Tell the care team when your last dose was given and what symptoms occurred and how soon they began.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Human Insulin-Specific IgE

Frequently asked questions

Does a positive result mean I will always react to insulin?
No. It indicates sensitization and must be interpreted alongside the timing and type of symptoms, other possible causes, and any prior reaction history.
Does this test measure my insulin level?
No. It measures IgE antibodies against human insulin; insulin concentration and blood glucose are measured with different tests.
What if I had a severe reaction after an insulin injection?
Seek urgent medical care for breathing difficulty, throat swelling, faintness, or other severe symptoms. A severe reaction should not wait for antibody test results.
  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 17, 2026. · Read our editorial policy