Unit Code 82441:
Electrophoresis, Protein, Urine
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
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


