Epic Test Code SESPF Sesame Seed, IgE, with Reflex to Sesame Seed Component, IgE, Serum
Ordering Guidance
For a listing of allergens available for testing, see Allergens - Immunoglobulin E (IgE) Antibodies
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
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
Evaluating patients with suspected sesame seed allergy
Reflex Tests
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
SESPR | Sesame Seed Component, IgE, S | No | No |
Testing Algorithm
Testing begins with analysis of total sesame seed IgE. If the sesame seed total IgE result is negative (<0.10 kU/L), testing is complete.
If the sesame seed total IgE result is 0.10 kU/L or more, then sesame seed component (Ses i 1) testing will be performed at an additional charge.
Special Instructions
Method Name
Fluorescent Enzyme Immunoassay (FEIA)
Reporting Name
Sesame Seed Component Reflex, SSpecimen Type
SerumSpecimen 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
De novo IgE sensitization to Sesamum indicum (sesame) seed and related products, such as sesame seed oil, can occur in both children and adults. In the United States, 0.21% of children and 0.24% of adults have reported convincing sesame allergy, but this varies around world. While sesame allergy is the ninth most common childhood food allergy in the United States, it is the third most common food allergy in Israel, with a prevalence of 0.93% in children. The allergy commonly lasts for life, with only 20% to 30% of children gaining tolerance to sesame seed. The median age onset for sesame allergy is 1 year. The use of whole sesame seed and its derivatives in food and health products is growing worldwide.
Sesame seed contains many components capable of eliciting an allergic response. A prospective multicenter European investigation suggests that sesame seed can cause allergic reactions that are more severe compared to other common seeds and nuts. In one study (n=16), 56% of patients developed urticaria while 38% presented with anaphylaxis after exposure to sesame seed. However, rhinitis and asthma have also been reported. Ses i 1 is the major allergenic component of sesame. 2S albumins, like Ses i 1, are extremely stable proteins, able to withstand temperatures up to 100° C, acidic conditions, and pepsin digestion. Consequently, immunological exposure to these proteins is thought to occur directly in the gut, resulting in sensitization or an allergic response. Seven sesame seed components are registered by the joint World Health Organization/International Union of Immunological Societies Allergen Nomenclature Subcommittee including Ses i 1 and Ses i 2 (2S albumin proteins), Ses i 3 (7S vicilin-like globulin), Ses i 4 and Ses i 5 (oleosins), and Ses i 6 and Ses i 7 (11S globulins). Ses i 1 is the major allergenic component of sesame.
Of all sesame protein components, serum IgE antibodies against Ses i 1 are the most useful for diagnosis of sesame allergy. Measurement of IgE against Ses i 1 for the diagnosis of sesame allergy was shown to have a sensitivity and specificity of 86.1% and 85.7%, respectively, using a cutoff of 3.96 kUa/L. Comparatively, measure of IgE against sesame extract (cutoff of 7.97 kUa/L) had a similar sensitivity of 83.3%, but a much lower specificity of 48.2% due to known cross-reactivity with peanut and tree nuts/seeds. In the same study, it was shown that 92% of symptomatic patients were sensitized to Ses i 1, while only 32% of nonsymptomatic patients were sensitized.
Despite minor homology between 2S albumins, crossreactivity with other 2S albumin proteins still exists, such as those found in sesame seed, hazelnuts, peanuts, English walnuts, Brazil nuts, cashews, pistachios, poppyseed, or rapeseed. For example, Ses i 1 and Ses i 2 are related the peanut allergens Ara h 2, 6, and 7. Sesame seed allergy can coexist with peanut and tree nut allergies, and co-sensitization with these allergens, alongside kiwi and rye, have been reported. There is varying prevalence of sesame seed and tree nut/peanut related allergy coexistence. Sesame seed allergy coexists with 15% to 54% of self-reported peanut allergies, 8% to 14.8% of tree nut allergies, and 50% to 54% of patients who have both tree nut and peanut allergies.
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.
Interpretation
If the total serum IgE antibody against sesame seed is detectable (≥0.10 IgE kUa/L), it is possible the patient has been sensitized to the components of sesame seed or other potential substances with cross activity. An additional test utilizing Ses i 1, a specific allergenic sesame seed component IgE antibody, will be performed to further confirm sensitization to sesame seed.
If the total serum IgE antibody against sesame seed is negative (<0.10 IgE kUa/L), the patient lacks detectable sensitization to sesame seed components. A report will be provided without additional testing performed. An oral food challenge may be helpful in the diagnosis of sesame seed allergy.
Cautions
Positive results for IgE antibody against total sesame seed IgE or specific component IgE indicate the sensitization to sesame seed or cross-reactive allergen only. Cross-reactivity and co-sensitization have been documented between allergens in sesame seed and various other foods, including, but not limited to, peanuts, hazelnuts, walnuts, black walnuts, cashews, macadamia nuts, pistachios, kiwis, rye, and poppy seeds. A positive result cannot be exclusively used for diagnosis of sesame seed-related allergy.
Negative results of total antibody against sesame seed IgE or sesame seed specific IgE antibody components only suggest the absence of sensitization to potential allergenic components of sesame seeds. A negative result does not exclude the possibility of allergy to sesame seeds.
IgE antibody testing may not offer useful results in patients previously treated with immunotherapy to ascertain residual clinical sensitivity or in cases where the medical management does not rely on the identification of allergen specificity.
False-positive results for IgE antibodies may manifest in patients with significantly elevated serum IgE levels (>2500 kU/L) due to nonspecific binding to allergen solid phases.
Day(s) Performed
Monday through Friday
Report Available
Same day/1 to 3 daysSpecimen Retention Time
14 daysPerforming Laboratory
Mayo Clinic Laboratories in RochesterCPT Code Information
86003
NY State Approved
YesForms
If not ordering electronically, complete, print, and send an Allergen Test Request (T236) with the specimen.