Test Code IGA Immunoglobulin A (IgA)
Additional Codes
Epic: LAB73
Specimen Required
Specimen Type: Serum
Collection Container/Type
Preferred: Serum gold
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 3 mL
Collection Instructions: Centrifuge and separate cells after clot formation and within 4 hours of collection.
Specimen Minimum Volume
0.25 mL
Specimen Stability
Room temperature: 8 months
Refrigerated: 8 months
Frozen: 8 months
Reference Range
Males
0 - 3 months: 1 - 34 mg/dL
>3 months: 8 - 91 mg/dL
1 - 12 years: 21 - 291 mg/dL
12 - 60 years: 63 - 484 mg/dL
>60 years: 101 - 645 mg/dL
Female
0 - 3 months: 1 - 34 mg/dL
>3 months: 8 - 91 mg/dL
1 - 12 years: 21 - 282 mg/dL
12 - 60 years: 65 - 421 mg/dL
>60 years: 69 - 517 mg/dL
Rejection Due To
Unlabeled, mislabeled, wrong tube type, hemolyzed, visually lipemic, QNS, exceeds specimen/stability requirements.
Report Available
Same day / 1 day
Clinical Significance
Approximately 10-15% of serum immunoglobulin is IgA. Serum
IgA is predominantly found in monomeric form with 10-15% as a
dimer. Secretory IgA, found in tears, sweat, saliva, milk,
colostrum and gastrointestinal and bronchial secretions, is
synthesized mainly by plasma cells in mucous membranes and breast
ductules. IgA can initiate complement activation by
alternative pathway. Secretory IgA plays a major role in the
protection of the respiratory, genitourinary, and gastrointestinal
tracts against infection. The specific role of serum IgA is
unclear, but may be important in virus neutralization.
Indications for serum IgA quantification include recurrent
infections, anaphylactic transfusion reactions, differentiation of
M-components in myeloma, and evaluation of progression of IgA
myeloma.
IgA does not cross the placenta, and as a result, IgA levels in
infants’ sera are very low. Serum IgA levels do not
reach adult concentrations until 12 years of age. Approximately one
in every 700 caucasians is genetically IgA deficient.
Individuals with absent IgA have a higher than expected
incidence of rheumatic disorders and lymphoma. Secondary IgA
deficiency is seen in non-IgA or multiple myeloma or
macroglobulinemia, and with nephrotic syndrome.
Elevated IgA levels are associated with both polyclonal as well as
monoclonal increases. Polyclonal increases include chronic
liver disease, chronic infections, and neoplasia of the lower GI
tract, inflammatory bowel disease, and autoimmune disease such as
rheumatoid arthritis. Monoclonal increases include IgA multiple
myeloma and occasionally other lymphomas.
Method Name
Immunoturbidimetric
Limitations
Samples containing paraproteins (abnormal monoclonal antibodies) may incorrectly fall within the reference range. Samples with elevated total protein concentrations or suspected paraproteinemia can be screened with other methods such as electrophoresis. Turbidity and particles in samples can interfere with the assay. Therefore, particulate matter should be removed by centrifugation prior to running the assay.
Day(s) Performed
Daily
LOINC
2458-8