Immunoglobulin A, Subclasses (1-2)

CPT: 82784; 82787(x2)
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Synonyms

  • IgA Subclasses
  • IgA1,2

Test Includes

Quantitation of IgA1, IgA2, total IgA


Expected Turnaround Time

3 - 6 days



Related Documents


Specimen Requirements


Specimen

Serum


Volume

2 mL


Minimum Volume

1 mL


Container

Red-top tube or gel-barrier tube


Collection

Transfer specimen to a plastic transport tube.


Storage Instructions

Maintain specimen at room temperature.


Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3


Causes for Rejection

Gross lipemia; hemolysis


Test Details


Use

Study IgA deficiencies in patients in association with recurrent sinopulmonary infections or repeated transfusions; study IgA elevations associated with IgA myeloma


Methodology

Immunologic


Additional Information

Two classes of IgA have been identified in humans: IgA1, which accounts for 80% to 90% of total serum IgA, and IgA2 which is the major subclass in secretions such as milk. The two subclasses appear to be regulated independently. Antigenic sites on the IgA subclasses are responsible for the anaphylactic transfusion reactions experienced by some patients totally deficient in either IgA1 or IgA2. After repeated transfusions, such patients may produce antibodies to these antigens. IgA subclasses are of further importance in that certain pathogenic microörganisms, including Haemophilus influenzae, are capable of enzymic cleavage of IgA1, leading to partial inactivation of this subclass. Recurrent sinopulmonary infections may, therefore, be related to deficiency of IgA2, which is resistant to these organisms. Grossly elevated levels of either subclass can occur in patients with IgA myeloma.


LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
123049 IgA, Subclasses (1-2) 001784 Immunoglobulin A, Qn, Serum mg/dL 2458-8
123049 IgA, Subclasses (1-2) 123050 IgA, Subclass 1 mg/dL 6886-6
123049 IgA, Subclasses (1-2) 123051 IgA, Subclass 2 mg/dL 6939-3

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