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Regional Allergen Mix 2–Specific IgE, Serum — Radioallergosorbent Test (RAST)

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

This blood test checks for IgE antibodies to the allergens included in a regional allergen mix 2 panel, helping assess possible allergic sensitization.

Quick summary

["A positive result suggests allergy sensitization to one or more allergens in the panel but must be interpreted with symptoms and exposure history."]

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

Key facts at a glance

LOINC
82104-1
Short code
Region Allerg Mix2 IgE RAST
Synonyms
Region Allerg Mix2 IgE RAST
Category
liver
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
multidisk
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 test measures allergen-specific IgE antibodies against the allergens in a regional allergen mix 2 panel. It is commonly reported using RAST, a laboratory method for detecting antibodies associated with allergic sensitization.

Why might I need this test?

Your clinician may order it to investigate sneezing, wheezing, skin symptoms, or other reactions that may be related to environmental allergies. The mix may help identify likely sensitivities when the specific trigger is not obvious.

How is the test performed?

A blood sample is drawn and tested in the laboratory for IgE directed against the allergens in the panel. The allergens represented in regional mix 2 can vary by laboratory, so review the test's allergen list with your clinician.

How do I prepare for the test?

No special preparation is usually required, and you generally do not need to stop allergy medicines for this test. Tell your clinician about biologic immune therapies or other medicines that may affect test interpretation.

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

Regional Allergen Mix 2 IgE

Frequently asked questions

Does a positive result mean I am allergic to every allergen in the panel?
No. A positive panel result may mean that IgE was detected to at least one included allergen, but it may not identify which one without individual allergen testing. Clinical history and sometimes additional testing are needed.
Can I stop taking my allergy medicine before this test?
Do not stop prescribed medicine unless your clinician instructs you to do so. Most antihistamines do not alter allergen-specific IgE results, while some biologic therapies and other immune treatments may affect interpretation.
How is this result different from a skin-prick allergy test?
This test measures allergen-specific IgE in blood, while a skin-prick test measures an immediate skin response after allergens are introduced. Both should be interpreted by a clinician in the context of your symptoms.
  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