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Crab (Allergen Specific IgE)

Crab (f23)

Test Codes

Antrim #31469, EPIC: LAB2111677, SOFT: ECRA

Department

Immunology

Specimen Collection Criteria

Collect: One Gold-top SST tube.

Twenty individual allergen assays or allergen screens can be performed on one 5 mL Gold-top SST tube. Each allergen assay requires 100 mcL of serum.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within two hours of collection.

Preparation for Courier Transport

Transport: Centrifuged collection tube, refrigerated (2-8°C or 36-46°F).

Rejection Criteria

Plasma specimens.

Severely lipemic or hemolyzed specimens.

In-Lab Processing

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Room temperature is acceptable for a maximum of two hours.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 1 month

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Royal Oak Special Testing Laboratory

Performed

Monday – Friday.
Results available the next business day.

Reference Range

Allergy Reference Range: Less than 0.35 kU/L. 

Range (kU/L)	Class	Interpretation
Less than or equal to 0.34	0	Negative
0.35-0.69	1	Low
0.70-3.49	2	Medium
3.50-17.49	3	High
17.50-49.99	4	Very High
50.0-100.0	5	Very High
Greater than 100	6	Very High

Test Methodology

Fluorescence Enzyme Immunoassay (FEIA).

Interpretation

The allergen class may not be predictive of clinical disease in some patients. The diagnosis of allergy should be based upon patient history and clinical findings. The diagnosis of allergy should not be based upon laboratory findings alone.

Clinical Utility

A positive test result (class 1 or greater) is indicative of the presence of allergen-specific IgE and suggests an increased likelihood of allergic disease.

Clinical Disease

The crab allergen has been responsible for fatal anaphylactic shock after ingestion. This allergen has also been identified as an occupational allergen for persons who come in contact with the dust from seafood or the water in which the food was boiled in. Cross-reactivity has been observed between crab, crawfish, shrimp, and lobster and common major allergens have also been observed in shrimp, lobster, and crawfish.

True food allergy is less common than popularly believed. It is estimated that only 1 to 4% of the general population suffers from a definite food allergy. Food allergy tends to be more common in children (up to 6%) than adults. In selected groups, such as children with eczema, the prevalence of food allergy may be as high as 25%.

The majority of the food allergies are due to the consumption of milk, egg, wheat, peanut, soy, tree nuts, fish and shellfish, however, allergic responses can occur with all types of food in a sensitized individual.

General symptoms of an allergy to food include nausea, vomiting, diarrhea, hives, itching, swelling of the mouth, tongue and/or lips, wheezing, and constriction of the airways in more severe reactions. Individuals with food allergies will typically show symptoms of an allergic response within 45 minutes of ingestion of food. Reactions to food ingestion occurring several hours after consumption is usually not related to allergies.

An anaphylactic reaction to food, which is life-threatening, occurs in approximately 1 million individuals each year according to the National Institutes of Health. Anaphylactic reactions are most commonly found in patients with allergies to peanuts, nuts, eggs, fish and shellfish. Anaphylactic responses occur approximately 5-15 minutes after food consumption and can lead to difficulty in breathing, constriction of the airways, and unconsciousness.

Certain factors such as alcohol consumption and exercise appear to enhance the reactivity to a food allergen in sensitized individuals. Individuals with food allergies usually have other allergies as well, including allergies to pollen or dust.

CPT Codes

86003
LOINC: 6092-1

Contacts

Last Updated

7/21/2024