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Order Code BLWRF Walnut-Food, IgE, with Reflex to Walnut-Food Components, 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: 1 mL

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


Useful For

Evaluation of patients with suspected walnut-food allergy

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
BLWX Walnut-Food Components, IgE, S No No

Testing Algorithm

Testing begins with analysis of walnut-food-specific total IgE. If walnut-food-specific total IgE result is negative (<0.10 kU/L), testing is complete.

 

If walnut-food-specific total IgE result is 0.10 kU/L or more, then walnut-food component (Jug r 1 and Jug r 3) testing will be performed at an additional charge.

Method Name

Fluorescent Enzyme Immunoassay (FEIA)

Reporting Name

Walnut-Food Component Reflex, S

Specimen Type

Serum

Specimen Minimum Volume

0.6 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

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.

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, Phadia; Rev 06/2020)

Day(s) Performed

Monday through Friday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

86003

Forms

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