Establishing a diagnosis of an allergy to isocyanate MDI
Defining the allergen responsible for eliciting signs and symptoms
Identifying allergens:
-Responsible for allergic disease and/or anaphylactic episode
-To confirm sensitization prior to beginning immunotherapy
-To investigate the specificity of allergic reactions to insect venom allergens, drugs, or chemical allergens
Fluorescence Enzyme Immunoassay (FEIA)
MDI
Methyl Dissocyanate
Serum
For a listing of allergens available for testing, see Allergens - Immunoglobulin E (IgE) Antibodies in Special Instructions
Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 0.5 mL for every 5 allergens requested
If not ordering electronically, complete, print, and send an Allergen Test Request (T236) with the specimen.
For 1 allergen: 0.3 mL
For more than 1 allergen: (0.05 mL x number of allergens) + 0.25 mL deadspace
Gross hemolysis | OK |
Gross lipemia | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 14 days | |
Frozen | 90 days |
Establishing a diagnosis of an allergy to isocyanate MDI
Defining the allergen responsible for eliciting signs and symptoms
Identifying allergens:
-Responsible for allergic disease and/or anaphylactic episode
-To confirm sensitization prior to beginning immunotherapy
-To investigate the specificity of allergic reactions to insect venom allergens, drugs, or chemical allergens
Clinical manifestations of immediate hypersensitivity (allergic)
In vitro serum testing for IgE antibodies provides an indication of the
The allergens chosen for testing often depend upon the age of the
Class | IgE kU/L | Interpretation |
0 | <0.35 | Negative |
1 | 0.35-0.69 | Equivocal |
2 | 0.70-3.49 | Positive |
3 | 3.50-17.4 | Positive |
4 | 17.5-49.9 | Strongly positive |
5 | 50.0-99.9 | Strongly positive |
6 | > or =100 | Strongly positive |
Reference values apply to all ages.
Detection of IgE antibodies in serum (Class 1 or greater) indicates
The level of IgE antibodies in serum varies directly with the
Testing for IgE antibodies is not useful in patients previously treated
Some individuals with clinically insignificant sensitivity to allergens
False-positive results for IgE antibodies may occur in patients with
Homburger HA, Hamilton RG: Chapter 55: Allergic diseases. In Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd edition. Edited by RA McPherson, MR Pincus. Elsevier, 2017, pp 1057-1070
Specific IgE from the patient's serum reacts with the allergen of interest, which is covalently coupled to an ImmunoCAP. After washing away nonspecific IgE, enzyme-labeled anti-IgE antibody is added to form a complex. After incubation, unbound anti-IgE is washed away and the bound complex is then incubated with a developing agent. After stopping the reaction, the fluorescence of the eluate is measured. Fluorescence is proportional to the amount of specific IgE present in the patient's sample (ie, the higher the fluorescence value, the more IgE antibody is present).(Package insert: ImmunoCAP System Specific IgE FEIA, Uppsala, Sweden Rev 06/2019)
Monday through Friday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
86003
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
IMDI | Isocyanate MDI, IgE | 7430-2 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
IMDI | Isocyanate MDI, IgE | 7430-2 |