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Unit Code 800052:
Immunoglobulin A (IgA), Serum

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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 that is contained in a background of polyclonal

immunoglobulins, 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

Key