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Test Code BETV2 BET v2 (Profilin), IgE, Serum


Ordering Guidance


For a listing of allergens available for testing, see Allergens - Immunoglobulin E (IgE) Antibodies.

 

BET v2 is also available as part of the PEANT / Peanut, IgE with Reflex to Peanut Components, IgE, Serum. This reflex test includes Ara h2, h1, h3, h6, h9, and Bet v2 (profilin) if the initial Peanut IgE test is detectable.



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.


Forms

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

Useful For

Evaluation of patients suspected birch pollen allergy

 

Evaluation of patients with suspected peanut allergy

 

Evaluation of patients with oral allergy syndrome to other pollens or plant-based foods

Method Name

Fluorescence Enzyme Immunoassay (FEIA)

Reporting Name

BET v2 (Profilin), IgE, S

Specimen Type

Serum

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
  Ambient  7 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Clinical Information

Immunoglobulin E antibodies to the Bet v 2a profilin protein have been reported in 10% to 38% of birch pollen-allergic patients. Birch pollen is highly allergenic and is a significant cause of immediate hypersensitivity, affecting as much as 5% to 50% of the population of Western Europe. The presence of antibodies to Bet v 2, may also indicate sensitivity to other profilin containing pollens including ragweed pollen, mugwort pollen, and timothy grass pollen.

 

The profilin Bet v2 is related to, and cross-reactive with, antibodies to the potential peanut allergen profilin Ara h5. As profilin proteins are present in many other foods, sensitivity to profilin Bet v2 may be associated in broad allergen cross-reactivity among foods, including mango, peach, apple, hazelnut, celery, carrot, paprika, anise, fennel, coriander, cumin, tomato, and potato.

 

The most common manifestation of allergy to food in profilin related allergic individuals is oral allergy syndrome. Profilins are generally not resistant to heat and digestion. Individuals with birch pollen allergy and oral allergy syndrome are more frequently allergic to apples and peaches than to other foods. In cases of allergic reaction associated with oral allergy syndrome, rhinitis, itching, tingling, and other mild reactions on the oropharyngeal mucosa were reported to be the most common complaints.

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 ≥0.70 kU/L (Class 2 and above) will flag as abnormally high.

Interpretation

Profilins are potentially cross-reactive allergenic proteins found in many plant pollens and tissues. IgE antibodies to the profilin Bet v2, while associated with birch pollen sensitivity, also represent a minor peanut allergen marker as it is cross-reactive with the peanut profilin Ara h5. The presence of antibodies to profilin Bet v2 is typically associated with milder allergic reactions and oral allergy syndrome.

Cautions

Results from IgE antibody testing must be interpreted in the context of patient’s clinical evaluation and history of allergen exposures.

 

The major allergen in birch pollen is Bet v1 (which is homologous to the peanut allergen Ara h8), as antibodies to the Bet v1 is found in as many as 95% in birch pollen patients. In cases of suspected birch pollen allergy, testing for antibodies to the profilin Bet v1 should be considered in addition to this test for profilin Bet v2 antibodies.

 

Positive results for IgE to peanut allergy markers, such as profilin Bet v2, are not diagnostic for peanut allergy and only indicate that the patient may be sensitized to peanut component or a cross-reactive allergen. Clinical correlation of results from in vitro IgE testing with patient history of allergic or anaphylactic responses to peanut is recommended.

 

Testing for IgE antibodies may not be 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.

 

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.

Specimen Retention Time

14 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

86008

LOINC Code Information

Test ID Test Order Name Order LOINC Value
BETV2 BET v2 (Profilin), IgE, S 30985-6

 

Result ID Test Result Name Result LOINC Value
BETV2 BET v2 (Profilin), IgE, S 30985-6

Day(s) Performed

Monday through Friday

Report Available

Same day/1 to 3 days