Test Code MISC2MAYOWEED4 Weed Panel # 4, Serum
Reporting Name
Weed Panel # 4Useful For
Establishing a diagnosis of an allergy to giant ragweed, short ragweed, and Western ragweed
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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
Testing for IgE antibodies is not useful in patients previously treated with immunotherapy to determine if residual clinical sensitivity exists, or in patients in whom the medical management does not depend upon identification of allergen specificity.
Testing Algorithm
Includes testing for giant ragweed, short ragweed, and Western ragweed allergen.
Performing Laboratory

Specimen Type
SerumOrdering Guidance
This test uses a pooled allergen reagent; therefore, the multi-allergen Immunocap (panel cap) is reported with a single qualitative class result and concentration. This is the appropriate first-tier test for allergic disease.
For a listing of allergens available for testing, see Allergens - Immunoglobulin E (IgE) Antibodies in Special Instructions
Specimen Required
Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 0.5 mL
Specimen Minimum Volume
0.3 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 14 days | |
Frozen | 90 days |
Special Instructions
Reference Values
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 |
≥100 |
Strongly positive |
Reference values apply to all ages.
Day(s) Performed
Monday through Friday
Test Classification
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
86003
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
WEED4 | Weed Panel # 4 | 73710-6 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
WEED4 | Weed Panel # 4 | 73710-6 |
Clinical Information
Clinical manifestations of immediate hypersensitivity (allergic) diseases are caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE antibodies interact with allergen.
In vitro serum testing for IgE antibodies provides an indication of the immune response to allergen(s) that may be associated with allergic disease.
The allergens chosen for testing often depend upon the age of the patient, history of allergen exposure, season of the year, and clinical manifestations. In individuals predisposed to develop allergic disease(s), the sequence of sensitization and clinical manifestations proceed as follows: eczema and respiratory disease (rhinitis and bronchospasm) in infants and children less than 5 years due to food sensitivity (milk, egg, soy, and wheat proteins) followed by respiratory disease (rhinitis and asthma) in older children and adults due to sensitivity to inhalant allergens (dust mite, mold, and pollen inhalants).
Interpretation
Positive results indicate the possibility of allergic disease induced by one or more allergens present in the multi-allergen cap.
Negative results may rule out allergy, except in rare cases of allergic disease induced by exposure to a single allergen.
Detection of IgE antibodies in serum (Class 1 or greater) indicates an increased likelihood of allergic disease as opposed to other etiologies and defines the allergens that may be responsible for eliciting signs and symptoms.
The level of IgE antibodies in serum varies directly with the concentration of IgE antibodies expressed as a class score or kU/L.
Method Description
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)
Report Available
1 to 3 daysReject Due To
Gross hemolysis | OK |
Gross lipemia | OK |
Method Name
Fluorescence Enzyme Immunoassay (FEIA)
Forms
If not ordering electronically, complete, print, and send an Allergen Test Request (T236) with the specimen.