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Test Code REPU Electrophoresis, Protein, Random, Urine

Reporting Name

Electrophoresis, Protein, Random, U

Useful For

Identifying monoclonal gammopathies using random urine specimens

Profile Information

Test ID Reporting Name Available Separately Always Performed
RPEU Protein Electrophoresis, Random, U No Yes
PTCON Protein, Total, Random, U No Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
RIFXU Immunofixation, Random, U No No

Testing Algorithm

Urine protein electrophoresis alone is not considered an adequate screening for monoclonal gammopathies. If a discrete electrophoresis band is identified, the laboratory will evaluate the urine protein electrophoresis and, if necessary, perform immunofixation at an additional charge.


The following algorithms are available in Special Instructions:

-Laboratory Approach to the Diagnosis of Amyloidosis

-Laboratory Screening Tests for Suspected Multiple Myeloma

Method Name

PTCON: Turbidimetry

RPEU: Agarose Gel Electrophoresis

RIFXU: Immunofixation

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type


Advisory Information

Random urine specimens may be sufficient for identifying monoclonal proteins, but 24-hour specimens should be used to quantitate and monitor urinary abnormalities. See MPSU / Monoclonal Protein Study, 24 Hour, Urine.

Shipping Instructions

Refrigerate specimen during collection and send refrigerated.

Necessary Information

Random urine, no volume is required.

Specimen Required

Supplies: Aliquot Tube, 5 mL (T465)

Submission Container/Tube: Plastic, 60-mL urine bottle and plastic, 5-mL tube (T465)

Specimen Volume: 50 mL

Collection Instructions:

1. Collect a random urine specimen.

2. Aliquot specimen between containers.

4. Label specimens appropriately (60-mL urine bottle for protein electrophoresis and 5-mL tube for protein, total).

Specimen Minimum Volume

25 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 14 days
  Frozen  5 days
  Ambient  72 hours

Reject Due To










Reference Values


No reference values apply to random urine.



The following fractions, if present, will be reported as a percent of the total protein:






No reference values apply to random urines.

Day(s) and Time(s) Performed

Total Protein: Monday through Sunday; Continuous

Protein Electrophoresis: Monday through Saturday; 12 p.m.

CPT Code Information

84156-Protein, total

84166-Electrophoresis, protein

86335-Immunofixation (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
REPU Electrophoresis, Protein, Random, U In Process


Result ID Test Result Name Result LOINC Value
33039 Albumin 13992-3
33040 Alpha 1-Globulin 13990-7
33041 Alpha 2-Globulin 13993-1
33042 Beta-Globulin 13994-9
33043 Gamma-Globulin 13995-6
33044 A/G Ratio 44293-9
33045 M spike 42483-8
33046 M spike 42483-8
33047 Impression 49299-1
PTCON Protein, Total, Random, U 2888-6

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

Method Description

Urine proteins are separated in an electric field according to their size, shape, and electric charge (Helena SPIFE 3000). The separation is performed on agarose gels (Helena SPIFE SPE Vis Gel). The proteins are visualized by staining with acid blue and the intensity of staining is quantitated by densitometry (Helena Quick Scan Touch). Multiplying by the urine protein concentration (Benzethonium Chloride) converts the percentage of protein in each fraction into urine concentration.(Kyle RA, Katzmann JA, Lust JA, Dispernzieri A: Immunochemical characterization of immunoglobulins. In Manual of Clinical Laboratory Immunology. Sixth edition. Edited by NR Rose Rose RG Hamilton, B Detrick. Washington, DC, ASM Press, 2002, pp 71-91)

Analytic Time

Same day/1 day

Specimen Retention Time

See Individual Unit Codes


A characteristic monoclonal band (M-spike) is often found in the urine of patients with monoclonal gammopathies. The initial identification of an M-spike or an area of restricted migration should be followed by 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 greater than 1 g/24 hours is consistent with a diagnosis of multiple myeloma or macroglobulinemia.


The presence of a small amount of monoclonal light chain and proteinuria (total protein >3 g/24 hours) that is predominantly albumin is consistent with primary systemic amyloidosis (AL) and light-chain deposition disease (LCDD).


Because patients with AL and LCDD may have elevated urinary protein without an identifiable M-spike, urine protein electrophoresis is not considered an adequate screen for these disorders and immunofixation is also recommended.

Clinical Information

Urine proteins can be grouped into 5 fractions by protein electrophoresis:





-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, primary systemic amyloidosis, and light-chain deposition disease.


The following algorithms are available in Special Instructions:

-Laboratory Approach to the Diagnosis of Amyloidosis

-Laboratory Screening Tests for Suspected Multiple Myeloma


Patients suspected of having a monoclonal gammopathy may have a normal urine protein electrophoretic pattern, and these patients should have immunofixation performed.


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


Hemolysis may cause a discrete band on protein electrophoresis, which will be negative on immunofixation.


Penicillin may split the albumin band.


Radiographic agents may produce an uninterpretable pattern.

Urine Preservative Collection Options

Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.








6N HCl


50% Acetic Acid








Boric Acid