Laboratory Services

Red Top, IgE, Serum

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Updated Test Information:

Test Description
Red Top, IgE, Serum
Synonym(s)

A. alba; A. canina L. - Valvet Bentgrass; A. capillaris L. - Colonial Bentgrass Agrostis Stolonifera; A. exarata - Spike Bentgrass; A. filifolia; A. gigantea; A. palustris; A. stolonifera x Agrostis tenuis - Cathedral or Victorian Bentgrass; A. tenuis - Highland Bentgrass; Agrostis spp.; Bent Grass; Carpet Grass; Creeping Bent Grass; Water Bent Grass

Test ID
REDT
General Information

Useful for:



  • Establishing a diagnosis of an allergy to red top

  • Defining the allergen responsible for eliciting signs and symptoms

  • Identifying allergens responsible for allergic disease and/or anaphylactic episode

  • Confirming sensitization prior to beginning immunotherapy

  • Investigating the specificity of allergic reactions to insect venom allergens, drugs, or chemical allergens

Specimen Type

Serum

Specimen Requirements

  • Preferred: Red Top

  • Acceptable: Serum Gel

Additional Processing Details

  • For 1 allergen: 0.3 mL

  • For more than 1 allergen: (0.05 mL x number of allergens) + 0.25 mL deadspace

Stability

  • Refrigerated (preferred): 14 days

  • Frozen: 90 days

Limitations

  • 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 results must be interpreted in the clinical context

  • False-positive results for IgE antibodies may occur in patients with markedly elevated serum IgE (>2,500 kU/L) due to nonspecific binding to allergen solid phases.

Methodology

Fluorescence Enzyme Immunoassay (FEIA)

Estimated TAT

1-3 days

Testing Schedule

Monday-Saturday

Retention

14 days

CPT Code(s)

86003

Reference Range
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
Performing Lab

Mayo

LOINC Code(s)

6228-1

Additional Information