Test Catalog

Test Id : BRAZR

Brazil Nut, IgE with Reflex to Brazil Nut Component, IgE, Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluation of patients with suspected Brazil nut allergy


The determination of the relative amount of IgE antibody to total Brazil nut, and IgE antibodies to the specific Brazil nut component, may aid in assessment of the potential strength and type of allergenic response to Brazil nut.


IgE antibody to total Brazil nut will be initially tested.


If detectable total Brazil nut IgE antibody is present, an additional specific component to the Brazil nut allergen antibody testing will be performed. This is comprised of testing for IgE antibodies to the potential allergen Ber e 1.

Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.

Test Id Reporting Name Available Separately Always Performed
BRAZX Brazil Nut Component, IgE, S No No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

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


If the Brazil nut-specific total IgE result is 0.10 kU/L or more, then the Brazil nut component (Ber e 1) test will be performed at an additional charge.

Method Name
A short description of the method used to perform the test

Fluorescent Enzyme Immunoassay (FEIA)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Brazil Nut Component Reflex, S

Lists additional common names for a test, as an aid in searching

Brazil nut component

Ber e 1

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

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


If the Brazil nut-specific total IgE result is 0.10 kU/L or more, then the Brazil nut component (Ber e 1) test will be performed at an additional charge.

Specimen Type
Describes the specimen type validated for testing


Ordering Guidance

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

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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.

Special Instructions
Library of PDFs including pertinent information and forms related to the test


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

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.4 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 14 days
Frozen 90 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluation of patients with suspected Brazil nut allergy

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

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


If the Brazil nut-specific total IgE result is 0.10 kU/L or more, then the Brazil nut component (Ber e 1) test will be performed at an additional charge.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Allergies to tree nuts are relatively prevalent and can result in severe reactions. The main culprits in tree nut allergies include walnut, almond, pistachio, cashew, pecan, hazelnut, macadamia, Brazil nut, and pine nuts. Tree nut allergy often appears in young children and estimates of prevalence range from 0.1% to greater than 5% of the population, dependent on geographical region.


In the case of nut-induced allergic reactions, as with many other foods, symptoms usually present within minutes of ingestion. Over 80% of reactions to tree nuts involve allergy related respiratory symptoms. Tree nut allergies are one of the most dangerous types of allergic reaction with 20% to 40% of cases of related anaphylaxis, and 70% to 90% of fatalities attributable to nut exposure (including peanut exposure).


Allergy to Brazil nut has reported within the United States population. Among those suffering from tree-nut-allergic individuals, the prevalence of Brazil nut allergy is estimated to be 10% to 20%. Brazil nut allergy occurs primarily through oral ingestion. Following oral exposure, allergy may be associated with systemic reactions, including respiratory and urticaria, occasionally resulting in anaphylaxis.


Ber e 1 is an abundant, heat and digestion resistant, storage protein component that is associated with systemic reactions to Brazil nuts. This major allergen component has been found to correlate with allergic symptoms. Exposure of the Ber e 1 at 100 degrees C for 20 minutes did not to reduce the potential allergenicity of the molecule. 


Immunological cross-reactivity has been reported between Brazil nut, hazelnut, cashew, pistachio, and almond, although cross reactivity with walnut, peanut, and coconut has also been reported. There is considerable homology between the 2S albumin of Brazil nut (Ber e 1) and other plant species, such as cottonseed, sunflower, rapeseed, castor bean, and sesame. Positive antibodies to total Brazil nuts may occur in cases of allergy to other Brazil nut storage proteins, profilins, or in the presence of cross-reacting carbohydrate determinants.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.


IgE kU/L



















Strongly positive



Strongly positive


> or =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.

Provides information to assist in interpretation of the test results

When detectable total Brazil nut IgE antibody is present (> or =0.10 IgE kUa/L), additional specific component IgE antibody testing will be performed. If a potential specific allergenic Brazil nut component IgE is detectable (> or =0.10 IgE kUa/L), an interpretive report will be provided.


When the sample is negative for total Brazil nut IgE antibody (<0.10 IgE kUa/L), further testing for specific Brazil nut component IgE antibodies will not be performed. A negative IgE result for total Brazil nut antibody may indicate a lack of sensitization to the potential Brazil nut allergenic component.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Clinical correlation of results from in vitro IgE testing with patient history of allergic or anaphylactic responses to Brazil nuts is recommended.


Negative results for IgE antibodies against Brazil nut extract or allergenic components do not completely exclude the possibility of clinically relevant allergic responses upon exposure.


Positive results for IgE to Brazil nuts or any potential Brazil nut allergenic components are not diagnostic for allergy and only indicate patient may be sensitized to Brazil nuts or a cross-reactive allergen.


Testing for IgE antibodies may not be useful in patients previously treated with immunotherapy to determine if residual clinical sensitivity exists or in patients whose medical management does not depend upon the 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.


Cross-reacting carbohydrate determinants may also result in positive total Brazil nut-specific IgE testing.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Salo PM, Arbes SJ Jr, Jaramillo R, et al. Prevalence of allergic sensitization in the United States: results from the National Health and Nutrition Examination Survey (NHANES) 2005-2006. J Allergy Clin Immunol. 2014;134(2):350-359. doi:10.1016/j.jaci.2013.12.1071

2. Waserman S, Watson W. Food allergy. Allergy Asthma Clin Immuno. 2011;7 Suppl 1(Suppl 1):S7

3. Abrams EM, Sicherer SH. Diagnosis and management of food allergy. CMAJ. 2016;188(15):1087-1093

4. Weinberger T, Sicherer S. Current perspectives on tree nut allergy: a review. J Asthma Allergy. 2018;11:41-51

5. Lomas JM, Jarvinen KM. Managing nut-induced anaphylaxis: challenges and solutions. J Asthma Allergy. 2015; 8:115-123

6. Maloney J, et al. The use of serum-specific IgE measurements for the diagnosis of peanut, tree nut, and seed allergy. J Allergy Clin Immunol. 2008;122(1):145-51

7. Sicherer SH, Burks AW, Sampson HA. Clinical features of acute allergic reactions to peanut and tree nuts in children. Pediatrics. 1998;102(1):e6

8. Crespo JF, James JM. Fernandez C, Rodriguez J. Food allergy: Nuts and tree nuts. Br J Nutr. 2006;96 Suppl 2:S95-102

9. Yang L, Clements S, Joks R. A retrospective study of peanut and tree nut allergy: Sensitization and correlations with clinical manifestations. [published online ahead of print, 2015 Feb 27]. Allergy Rhinol (Providence). 2015;doi:10.2500/ar.20105.6.0108

10. Masthoff L, Hoff R, Verhoeckx KC, et al. A systematic review of the effect of thermal processing on the allergenicity of tree nuts. Allergy. 2013;3;68(8):983-993

11. Borja JM, Bartolome B, Gomez E, Galindo PA, Feo F. Anaphylaxis from Brazil nut. Allergy. 1999;54(9):1007-1008

12. Mazokopakis EE, Liontiris MI. Commentary: Health concerns of Brazil nut consumption. J Altern Complement Med. 2018;24(1):3-6

13.McWilliam V, Koplin J, Lodge C, Tang M, Dharmage S, Allen K. The prevalence of tree nut allergy: A systematic review. Curr Allergy Asthma Rep. 2015;15(9):54.

14.Rayes H, Raza AA, Williams A, Matthews S, Arshad SH. Specific IgE to recombinant protein (Ber e 1) for the diagnosis of Brazil nut allergy. Clin Exp Allergy. 2016;46(4):654-656.

15.Pastorello EA, Farioli L, Pravettoni V, Ispano M, Conti A, Ansaloni R, et al. Sensitization to the major allergen of Brazil nut is correlated with the clinical expression of allergy. J Allergy Clin Immunol. 1998;102(6 Pt 1):1021-1027.

16. Moreno FJ, Clemente A. 2S Albumin storage proteins: What makes them food allergens? Open Biochem J. 2008;2:16-28

Method Description
Describes how the test is performed and provides a method-specific reference

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)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 to 3 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


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Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
BRAZR Brazil Nut Component Reflex, S 6050-9
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
BRAZ1 Brazil Nut, IgE, S 6050-9

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | PHP Pdf | CMS Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports