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HelpTest Code WEED1 Weed Panel # 1, Serum
Reporting Name
Weed Panel # 1Useful For
Establishing a diagnosis of an allergy to English plantain, lamb's quarters, mugwort, Russian thistle, and short ragweed allergen
Defining the allergen responsible for eliciting signs and symptoms
Identifying allergens:
-Responsible for allergic response 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
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 English plantain, lamb's quarters, mugwort, Russian thistle, and short ragweed allergen.
Method Name
Fluorescence Enzyme Immunoassay (FEIA)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
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.
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL for every 5 allergens requested
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
For 1 allergen: 0.3 mL
For more than 1 allergen: (0.05 mL x number of allergens) + 0.25 mL deadspace
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 14 days | |
| Frozen | 90 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
Special Instructions
Reference Values
|
Class |
IgE kU/L |
Interpretation |
|
0 |
<0.10 |
Negative |
|
0/1 |
0.10-0.34 |
Borderline/equivocal |
|
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
CPT Code Information
86003
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| WEED1 | Weed Panel # 1 | 24480-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| WEED1 | Weed Panel # 1 | 24480-6 |
Clinical Information
Clinical manifestations of immediate hypersensitivity (allergic) diseases are caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from IgE-sensitized effector cells (mast cells and basophils) when cell-bound IgE antibodies interact with an allergen.
In vitro serum testing for IgE antibodies provides an indication of the immune response to allergens 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, 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.
Cautions
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.
Some individuals with clinically insignificant sensitivity to allergens may have measurable levels of IgE antibodies in serum, and test results must be interpreted in the clinical context.
False-positive results for IgE antibodies may occur in patients with markedly elevated serum IgE (>2500 kU/L) due to nonspecific binding to allergen solid phases.
Since only one result is generated for this panel, individual (single) allergen responses cannot be identified. When this panel is positive, follow-up testing is required to differentiate between individual allergens in the panel.