Unit Code 8157:
Immunoglobulin A (IgA), Serum
Useful For
Detection or monitoring of monoclonal gammopathies and immune
deficiencies
Clinical Information
The gamma-globulin band as seen in conventional serum protein
electrophoresis consists of 5 immunoglobulins. In normal serum,
about 15% is IgA.
Monoclonal gammopathies of all types may lead to a spike in the
gamma-globulin zone seen on serum protein electrophoresis.
Monoclonal elevation of IgA characterize multiple myeloma.
Decreased immunoglobulin levels are found in patients with congenital
deficiencies.
Reference Values
0-4 months: 5-64 mg/dL
5-8 months: 10-87 mg/dL
9-14 months: 17-94 mg/dL
15-23 months: 22-178 mg/dL
2-3 years: 24-192 mg/dL
4-6 years: 26-232 mg/dL
7-9 years: 33-258 mg/dL
10-12 years: 45-285 mg/dL
13-15 years: 47-317 mg/dL
16-17 years: 55-377 mg/dL
> or = 18 years: 50-400 mg/dL
Interpretation
Increased serum immunoglobulin concentrations occur due to
polyclonal or oligoclonal immunoglobulin proliferation in hepatic
disease (hepatitis, liver cirrhosis), connective tissue diseases,
acute and chronic infections, as well as in the cord blood of
neonates with intra uterine and perinatal infections.
Elevation of IgA may occur in monoclonal gammopathies such as
multiple myeloma, primary systemic amyloidosis, monoclonal gammo-
pathy of undetermined significance, and related disorders.
Decreased levels are found in patients with primary or secondary
immune deficiencies.
Cautions
Electrophoresis is usually required to interpret an elevated
immunoglobulin class as polyclonal versus monoclonal.
Immunofixation is usually required to characterize
a monoclonal protein.
If there is a discrete M-peak, the monoclonal protein can be
monitored with quantitative immunoglobulins.
If immunoglobulin quantitation is used to monitor the size of a
monoclonal protein which is contained in a background of polyclonal
immunoglobulins, however, changes in the immunoglobulin quantitation
may reflect changes in the background immunoglobulins, and serum
protein electrophoresis should therefore be used to monitor the
monoclonal protein.
Clinical Reference
1. Webster ADB: Laboratory investigation of primary deficiency
of the lymphoid system. In Clinics in Immunology and Allergy.
Vol. 5. 3rd edition. Philadelphia, WB Saunders Company, 1985,
pp 447-468
2. Pinching AJ: Laboratory investigation of secondary immunodeficiency.
In Clinics in Immunology and Allergy. Vol. 5. 3rd edition. Philadelphia,
WB Saunders Company, 1985, pp 469-490
3. Dispenzieri A, Gertz MA, Kyle RA: Distribution of diseases associated
with moderate polyclonal gammopathy in patients seen at Mayo
Clinic during 1991. 1997;Blood 90:353
4. Kyle RA, Greipp PR: The laboratory investigation of monoclonal
gammopathies. Mayo Clin Proc 1978;53:719-739
5. Ballow M, O'Neil KM: Approach to the patient with recurrent
infections. In Allergy: Principles and Practice. Vol. 2. 4th
edition. Edited by E Middleton Jr, CE Reed, EF Ellis, et al. St.
Louis, MO, Mosby-Year Book, Inc., 1993, pp 1027-1058
6. Kyle RA: Detection of quantitation of monoclonal proteins. Clin
Immunol Newsletter 1990;10:84-86
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