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Test Code CASHR Cashew, IgE with Reflex to Cashew Component, IgE, Serum


Ordering Guidance


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: 0.6 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Useful For

Evaluation of patients with suspected cashew allergy

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CASHX Cashew Component, IgE, S No No

Method Name

Fluorescent Enzyme Immunoassay (FEIA)

Reporting Name

Cashew Component Reflex, S

Specimen Type

Serum

Specimen Minimum Volume

0.4 mL

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
Gross icterus OK

Clinical Information

Allergies to tree nuts are relatively prevalent and can result in severe reactions. The main culprits in tree nut allergies include walnut, almond, pistachio, cashew, pecan, hazelnut, macadamia, Brazil nut, and pine nuts. Tree nut allergy often appears in young children and estimates of prevalence range from 0.1% to greater than 5% of the population, dependent on geographical region.

 

In the case of nut-induced allergic reactions, as with many other foods, symptoms usually present within minutes of ingestion. Over 80% of reactions to tree nuts involve allergy related respiratory symptoms. Tree nut allergies are one of the most dangerous types of allergic reaction with 20% to 40% of cases of related anaphylaxis and 70% to 90% of fatalities attributable to nut exposure, including peanut exposure.

 

Ana o 3 is a heat and digestion stable storage protein found in high abundance in cashew nuts. Approximately 80% of those with cashew allergy exhibit reactivity to the Ana o 3 component. Cashew nut allergy is often associated with severe reactions. Sensitization with Ana o 3 is associated with anaphylaxis in system reactions.

 

Severe reactions in those with cashew nut allergy occur at a higher frequency than in those with peanut allergy. Cashews can be found in Asian cuisines, pesto, and nut butter. Cooking will not destroy the allergenic potential of Ana o 3 f. In addition to being severe, cashew nut allergy is persistent and can manifest early in life. Co-sensitization has been repeated between pistachio, walnuts, and, to a lesser extent, hazelnut.

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

Concentrations of 0.70 kU/L or more (class 2 and above) will flag as abnormally high.

Reference values apply to all ages.

Day(s) Performed

Monday through Friday

Report Available

Same day/1 to 3 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

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.

CPT Code Information

86003

Forms

If not ordering electronically, complete, print, and send an Allergen Test Request (T236) with the specimen.