Identifying monoclonal gammopathies using random urine specimens
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
RPEU | Protein Electrophoresis, Random, U | No | Yes |
PTCON | Protein, Total, Random, U | No | Yes |
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
RIFXU | Immunofixation, Random, U | No | No |
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:
PTCON: Turbidimetry
RPEU: Agarose Gel Electrophoresis
RIFXU: Immunofixation
Bence Jones Urine
Heavy Chains Urine
Immunoelectrophoresis, Urine
Immunofixation Electrophoresis (IFE)
Immunofixation, Urine
Kappa Chains Urine
Lambda Chains Urine
Light Chains Urine
Paraprotein
Special Protein Studies, Urine
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:
Urine
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.
Refrigerate specimen after collection and send refrigerated.
Supplies:
-Urine Container, 60 mL (T313)
-Sarstedt 5 mL Aliquot Tube (T914)
Submission Container/Tube: Plastic, 60-mL urine bottle and plastic, 5-mL tube
Specimen Volume: 50 mL
Collection Instructions:
2. Aliquot at least 25-mL specimen in plastic, 60-mL urine bottle and at least 1-mL of specimen in plastic, 5-mL tube.
3. Label specimens appropriately (60-mL bottle for protein electrophoresis and 5-mL tube for protein, total).
25 mL
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 14 days | |
Frozen | 5 days | ||
Ambient | 24 hours |
Identifying monoclonal gammopathies using random urine specimens
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:
Urine proteins can be grouped into 5 fractions by protein electrophoresis:
-Albumin
-Alpha-1-globulin
-Alpha-2-globulin
-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, primary systemic amyloidosis, and light-chain deposition disease.
The following algorithms are available:
-Amyloidosis: Laboratory Approach to Diagnosis
-Multiple Myeloma: Laboratory Screening
PROTEIN, TOTAL
No reference values apply to random urine.
ELECTROPHORESIS, PROTEIN
The following fractions, if present, will be reported as mg/dL:
-Albumin
-Alpha-1-globulin
-Alpha-2-globulin
-Beta-globulin
-Gamma-globulin
No reference values apply to random urines.
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 chains and light chains.
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.
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.
1. Abraham RS, Barnidge DR: Protein analysis in the clinical immunology laboratory. In: Detrick B, Hamilton RG, Schmitz JL, eds. Molecular and Clinical Laboratory Immunology. 8th ed Wiley; 2016:chap 4
2. Keren DF, Humphrey RL: Clinical indications and applications for serum and urine protein electrophoresis and immunofixation. In: Detrick B, Hamilton RG, Schmitz JL, eds. Molecular and Clinical Laboratory Immunology. 8th ed. Wiley; 2016:chap 8
Urine proteins are separated in an electric field according to their size, shape, and electric charge (Helena Touch). The separation is performed on agarose gels. 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.(Instruction manual: Helena SPIFE Touch. Helena Laboratories, Corp; 11/2016; package insert: Helena SPIFE Touch SPE Pro 277. Helena Laboratories, Corp; 06/2018; Sykes E, Posey Y: Immunochemical characterization of immunoglobulins in serum, urine, and cerebrospinal fluid. In: Detrick B, Hamilton RG, Schmitz JL, eds. Molecular and Clinical Laboratory Immunology. 8th ed. Wiley; 2016:chap 9)
Total Protein: Monday through Sunday
Protein Electrophoresis: Monday through Friday
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
84156
84166
86335-Immunofixation (if appropriate)
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
REPU | Electrophoresis, Protein, Random, U | 34539-7 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
33044 | A/G Ratio | 44293-9 |
33045 | M spike | 40661-1 |
33046 | M spike | 40661-1 |
33047 | Impression | 49299-1 |
607975 | Albumin | 6942-7 |
607976 | Alpha-1 globulin | 9734-5 |
607977 | Alpha-2 globulin | 38190-5 |
607978 | Beta globulin | 9744-4 |
607979 | Gamma globulin | 9745-1 |
PTCON | Protein, Total, Random, U | 2888-6 |