Test Details
Methodology
Thermo Fisher ImmunoCAP® Allergen-specific IgE
Result Turnaround Time
3 - 5 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
Egg white; Reflex criteria: If egg white IgE ≥0.35 kU/L, ovalbumin IgE and ovomucoid IgE will be performed.
Use
The measurement of specific immunoglobulin E (IgE) to individual components of an allergen, either purified native or recombinant, is referred to as component resolved diagnosis (CRD).1-4 This approach represents an improvement over traditional measurement of IgE to allergen extracts that contain a mixture of proteins. The pattern of specific IgE reactivity to component allergens can predict which patients are at higher risk for systemic allergic reactions versus those who are sensitized but clinically tolerant. CDR can also be used to predict which patients are at risk for more severe reactions and which patients are likely to have milder symptoms.
Limitations
Allergen-specific IgE assays do not demonstrate absolute positive and negative predictive values for allergic disease. Clinical history must be incorporated into the diagnostic determination. Although the use of component resolved IgE testing may enhance the evaluation of potentially allergic individuals over the use of whole extracts alone, it cannot yet replace clinical history and oral food challenge in most cases. Sensitization against thus far unidentified determinants that are not found in the whole extract or in components might cause symptoms in rare cases.
Footnotes
Custom Additional Information
After cow’s milk, allergy to hen’s egg is the second most common allergy in infants and young children, affecting 1% to 2% of this population.5-9 A significant portion of children with hen’s egg allergy will outgrow their allergy.5,6 Egg allergy can cause severe allergic reactions in sensitized children and egg avoidance can cause significant dietary limitations. Several studies suggest that early sensitization to egg is a precursor to later sensitization to aeroallergens and the development of asthma.5,6
Egg Components
• Gal d 1 is the dominant egg allergen; it is highly allergenic and very stable to heat.8-11
• High levels of specific IgE antibodies to Gal d 1 indicate persistent egg allergy.8,12,13
• Low levels of specific IgE antibodies to Gal d 1 in early infancy suggest a good prognosis for outgrowing the egg allergy.14
• Gal d 1 specific IgE levels over time generally decrease as tolerance develops.14
• The majority of children with egg allergy will tolerate extensively heated or baked egg.7,15
• Significant levels of specific IgE antibodies to Gal d 1 indicate a risk for clinical reactions to both raw and cooked egg.15,16
• Children with low or undetectable levels of IgE antibodies to Gal d 1 have a high likelihood of tolerating boiled egg and extensively heated egg, eg, in cakes and cookies.7,12,15,16
• Quantification of Gal d 1-specific IgE can be useful in guiding the physician in the decision when to perform an oral food challenge test as well as to reduce the risk of serious reactions during OFC.9,16-19
• Gal d 2 is the most abundant protein in egg, but is easily denatured when heated.9,10,20
• Egg allergic patients sensitized to Gal d 2 may experience allergic reactions upon influenza and yellow fever vaccinations.21
Specimen Requirements
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube or gel-barrier tube
Storage Instructions
Room temperature
LOINC® Map
Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
---|---|---|---|---|---|---|
603940 | IgE Egg White w/Component Rflx | 6106-9 | 602444 | Class Description | N/A | |
603940 | IgE Egg White w/Component Rflx | 6106-9 | 606841 | F001-IgE Egg White | kU/L | 6106-9 |
Order Code | 603940 | |||||
Order Code Name | IgE Egg White w/Component Rflx | |||||
Order Loinc | 6106-9 | |||||
Result Code | 602444 | |||||
Result Code Name | Class Description | |||||
UofM | ||||||
Result LOINC | N/A | |||||
Order Code | 603940 | |||||
Order Code Name | IgE Egg White w/Component Rflx | |||||
Order Loinc | 6106-9 | |||||
Result Code | 606841 | |||||
Result Code Name | F001-IgE Egg White | |||||
UofM | kU/L | |||||
Result LOINC | 6106-9 |
Order Code | Order Name | Result Code | Result Name | UofM | Result LOINC | |
---|---|---|---|---|---|---|
Reflex 1 | 603851 | Panel 603851 | 602791 | F232-IgE Ovalbumin | kU/L | 7556-4 |
Reflex 1 | ||||||
Order Code | 603851 | |||||
Order Name | Panel 603851 | |||||
Result Code | 602791 | |||||
Result Name | F232-IgE Ovalbumin | |||||
UofM | kU/L | |||||
Result LOINC | 7556-4 |
Order Code | Order Name | Result Code | Result Name | UofM | Result LOINC | |
---|---|---|---|---|---|---|
Reflex 1 | 603851 | Panel 603851 | 602792 | F233-IgE Ovomucoid | kU/L | 7557-2 |
Reflex 1 | ||||||
Order Code | 603851 | |||||
Order Name | Panel 603851 | |||||
Result Code | 602792 | |||||
Result Name | F233-IgE Ovomucoid | |||||
UofM | kU/L | |||||
Result LOINC | 7557-2 |