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Unit Code 82441:
Electrophoresis, Protein, Urine

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Useful For

Monitoring patients with monoclonal gammopathies

  

Urine protein electrophoresis alone is not considered an

adequate screening for monoclonal gammopathies

Clinical Information

Urine proteins can be grouped into 5 fractions by protein

electrophoresis (PEL):

  - Albumin

  - Alpha-1

  - Alpha-2

  - Beta-globulin

  - Gamma-globulin

The urine total protein concentration, the electrophoretic

pattern, and the presence of a monoclonal immunoglobulin

light chain may be characteristic of monoclonal gammopathies

such as multiple myeloma (MM), primary systemic anyloidosis

(AL), and light chain deposition disease (LCDD).

Reference Values

PROTEIN, TOTAL:

<102 mg/24 hours

ELECTROPHORESIS, PROTEIN

If protein concentration is abnormal, the following fractions,

if present, will be reported as a percent of the protein, total. 

Albumin

Alpha-1-globulin

Alpha-2-globulin

Beta-globulin

Gamma-globulin 

Reference value applies to 24-hour collection. Specimens collected

for periods other than 24 hours will be reported in concentration units.

Interpretation

A characteristic monoclonal band (M-spike) is often found in the

urine of patients with MM. The initial identification of an M-spike

or an area of restricted migration should be followed by  #8823

"Monoclonal Protein Study, Urine"  that includes immunofixation to

identify the immunoglobulin heavy chain and/or light chain.

Immunoglobulin heavy chain fragments as well as free light chains

may be seen in the urine of patients with monoclonal gammopathies.

  

The presence of a monoclonal light chain M-spike of >1 g/24 hours is

consistent with a diagnosis of MM or macroglobulinemia.

  

The presence of a small amount of monoclonal light chain and

proteinuria (total protein >3 g/24 hrs) which is predominantly

albumin is consistent with AL or LCDD. Because patients with AL

and LCDD may have elevated urinary protein without an

identifiable M-spike, urine PEL is not considered an adequate

"screen" for the disorder. #8823 "Monoclonal Protein Study, Urine"

 that includes immunofixation should be performed if the

clinical suspicion is high.

Cautions

Patients suspected of having a monoclonal gammopathy may have a

normal urine protein electrophoretic pattern, and these patients should

have immunofixation (#8823 Monoclonal Protein Study, Urine) performed.

Monoclonal gammopathies are rarely seen in patients <30 years of age.

 

Hemolysis may cause a discrete band on PEL, which will be negative

on immunofixation.

 

Penicillin may split the albumin band.

 

Radiographic agents may produce an uninterpretable pattern.

Special Instructions and Forms

• Urine Preservatives 

Clinical Reference

1.   Kyle, RA, Katzmann, JA, Lust, JA, Dispenziei A: Clinical

      indications and applications of electrophoresis and

      immunofixation. In: Manual of Clinical Laboratory

      Immunology. 6th edition Edited by NR Rose, et al.  Washington,

      DC: ASM Press, 2002, pp66-67

 

2.   Kyle, RA, Katzmann, JA, Lust, JA, Dispernzieri, A:

      Immunochemical characterization of immunoglobulins.

      In: Manual of Clinical Laboratory Immunology. 6th  edition,

      Edited by N.R. Rose, et al, . Sixth Edition. Washington, DC: ASM

      Press, 2002, pp71-91

Key