Test Catalog

Test Id : IGAS

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IgA Subclasses, Serum

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Overview

Test Catalog

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

Investigation of immune deficiency due to IgA2 deficiency

 

Evaluating patients with anaphylactic transfusion reactions

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

Turbidimetry

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

Yes

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

IgA Subclasses, S

Specimen Type
Describes the specimen type validated for testing

Serum

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

Supplies: Sarstedt Aliquot Tube 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable:  Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

0.5 mL

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

Gross hemolysis OK
Gross lipemia Reject
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) 7 days
Ambient 7 days
Frozen 7 days

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

Investigation of immune deficiency due to IgA2 deficiency

 

Evaluating patients with anaphylactic transfusion reactions

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

Immunoglobulin A (IgA), the predominant immunoglobulin secreted at mucosal surfaces and the second most abundant immunoglobulin in serum, consists of 2 subclasses, IgA1 and IgA2. These subclasses differ in their molecular structure and tissue distribution. IgA1 is the major (approximately 80%) subclass in serum. It has a longer hinge region making it more susceptible to proteolytic cleavage. IgA2 is the major subclass in secretions such as milk, tears, sweat, and saliva. Although IgA deficiency is a common defect (1 in 700), it is usually asymptomatic. IgA deficiency with or without IgG subclass deficiency, however, can lead to recurrent pulmonary and gastrointestinal infections. In selective IgA deficiency, both IgA1 and IgA2 are deficient. It is also possible that only one of the subclasses is deficient. Some infections (eg, recurrent sinopulmonary infections with Haemophilus influenzae) may be related to a deficiency of IgA2, even in the presence of normal total IgA concentrations.

 

Paradoxically, bacterial infections may also cause IgA deficiency. IgA2 is more resistant to bacterial destruction than IgA1. Certain bacteria can cleave and inactivate IgA1, but not IgA2, thus depleting most of the IgA. In the presence of a concurrent IgA2 deficiency, infection by these organisms results in an apparent IgA deficiency.

 

IgA deficiency is a cause of anaphylactic transfusion reactions. In these situations, patients who are IgA deficient produce anti-IgA antibodies that react with IgA present in the transfusion product. While transfusion reactions typically occur in patients who have no detectable concentrations of IgA, they can also occur in patients with measurable IgA. In these situations, the complete deficiency of 1 of the IgA subclasses may be the cause of the transfusion reactions.

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.

IgA

1-3.9 years: 5-194 mg/dL

4-6.9 years: 16-210 mg/dL

7-9.9 years: 27-227 mg/dL

10-11.9 years: 35-241 mg/dL

12-13.9 years: 43-252 mg/dL

14-15.9 years: 50-263 mg/dL

16-17.9 years: 57-274 mg/dL

>18 years: 85-499 mg/dL

 

IgA1

1-3.9 years: 6-163 mg/dL

4-6.9 years: 16-186 mg/dL

7-9.9 years: 26-209 mg/dL

10-11.9 years: 34-228 mg/dL

12-13.9 years: 40-243 mg/dL

14-15.9 years: 46-259 mg/dL

16-17.9 years: 53-274 mg/dL

>18 years: 76-328 mg/dL

 

IgA2

1-3.9 years: <0.5-12.4 mg/dL

4-6.9 years: <0.5-25.7 mg/dL

7-9.9 years: 1.5-38.9 mg/dL

10-11.9 years: 2.9-49.9 mg/dL

12-13.9 years: 4.0-58.7 mg/dL

14-15.9 years: 5.2-67.5 mg/dL

16-17.9 years: 6.3-76.3 mg/dL

>18 years: 6.9-114.3 mg/dL

Interpretation
Provides information to assist in interpretation of the test results

Low concentrations of IgA2 with normal amounts of IgA1 suggest an IgA2 deficiency.

 

Elevated concentrations of IgA2 with normal or low amounts of IgA1 suggest a clonal plasma cell proliferative disorder secreting a monoclonal IgA2.

 

Increased total IgA concentrations may also be seen in benign disorders (eg, infection, inflammation, allergy), hyper IgD syndrome with periodic fever, and monoclonal gammopathies (eg, myeloma, monoclonal gammopathies of undetermined significance [MGUS]).

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

Quantitation of specific proteins by nephelometric means may not be possible in lipemic sera due to the extreme light scattering properties of the specimen. Turbidity and particles in the specimen may result in extraneous light scattering signals, resulting in variable specimen analysis.

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

1. Schauer U, Stemberg F, Rieger CHL, et al. Establishment of age-dependent reference values for IgA subclasses. Clin Chim Acta. 2003;328(1-2):129-133

2. Saulsbury FT. Hyperimmunoglobulinemia D and periodic fever syndrome (HIDS) in a child with normal serum IgD, but increased serum IgA concentration. J Pediatrics. 2003;143(1):127-129

3. Popovsky MA. Transfusion Reactions. American Association of Blood Banks, 3rd ed, 2007

4. Derksen VFAM, Allaart CF, Van der Helm-Van Mil AHM, Huizinga TWJ, Toes REM, van der Woude D. In rheumatoid arthritis patients, total IgA1 and IgA2 levels are elevated: implications for the mucosal origin hypothesis. Rheumatology (Oxford). 2022;62(1):407-416. doi:10.1093/rheumatology/keac237

5. Dietzen DJ, Willrich MAV. Amino acids, peptides, and proteins. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. 2023:chap 31

6. Steffen U, Koeleman CA, Sokolova MV, et al. IgA subclasses have different effector functions associated with distinct glycosylation profiles. Nat Commun. 2020;11(1):120. Published 2020 Jan 8. doi:10.1038/s41467-019-13992-8

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

The determination of soluble antigen concentration by turbidimetric methods involves the reaction with specific antiserum to form insoluble complexes. When light is passed through the suspension formed, a portion of the light is transmitted and focused onto a photodiode by an optical lens system. The amount of transmitted light is indirectly proportional to the specific protein concentration in the test sample. Concentrations are automatically calculated by reference to a calibration curve stored within the instrument.(Package inserts: Optilite IgA Kit. The Binding Site Group, Ltd; ver 5, 08/2015; Optilite IgA1. The Binding Site Group, Ltd; ver 19, 04/2016; Optilite IgA2. The Binding Site Group, Ltd; ver 11, 02/2015)

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

No

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.

Tuesday, 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

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

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.

82784

82787 x 2

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
IGAS IgA Subclasses, S 87552-6
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.
IGA_ IgA 2458-8
IGA1_ IgA1 6886-6
IGA2_ IgA2 6939-3

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 | 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

Test Update Resources

Change Type Effective Date
File Definition - Algorithm 2024-09-24