Diagnosing monoclonal gammopathies
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
RPEU | Protein Electrophoresis, Random, U | No | Yes |
RIFXU | Immunofixation, Random, U | No | Yes |
PTCON | Protein, Total, Random, U | No | Yes |
The following algorithms are available:
PTCON: Turbidimetry
RPEU: Agarose Gel Electrophoresis
RIFXU: Immunofixation
Bence Jones Urine
Heavy Chains Urine
Immunoelectrophoresis, Urine
Immunofixation, Urine
Kappa Chains Urine
Lambda Chains Urine
Light Chains Urine
Paraprotein
Special Protein Studies, Urine
Immunofixation Electrophoresis (IFE)
The following algorithms are available:
Urine
The use of a random urine specimen is sufficient for identifying the presence or absence of a monoclonal immunoglobulin, but a 24-hour specimen is preferred for quantitating and monitoring the abnormality. See MPSU / Monoclonal Protein Study, 24 Hour, Urine.
Refrigerate specimen during 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:
1. Collect a random urine specimen.
2. Aliquot at least 25-mL of specimen into a plastic, 60-mL urine bottle and at least 1-mL of specimen into a plastic, 5-mL tube.
3. Label specimens appropriately (60-mL bottle for protein electrophoresis and 5-mL tube for protein, total)
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
25 mL
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 14 days | |
Frozen | 5 days | ||
Ambient | 24 hours |
Diagnosing monoclonal gammopathies
The following algorithms are available:
Urine proteins can be grouped into 5 fractions by protein electrophoresis:
-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, primary systemic amyloidosis, and light-chain deposition disease.
The following algorithms are available:
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
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 is followed by immunofixation to identify the immunoglobulin heavy chains and light chains.
Immunoglobulin free light chains as well as heavy chain fragments 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) or light-chain deposition disease (LCDD).
Because patients with AL or 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.
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
Electrophoresis:
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; 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)
Immunofixation:
Urine proteins are separated in an electric field according to their size, shape, and electric charge. The separation is performed on agarose gels (Helena SPIFE Immunofix-15). The proteins are anchored in situ following electrophoresis. Antisera specific for gamma, alpha, mu, kappa, and lambda immunoglobulin heavy and light chains are applied to the gel forming insoluble complexes with any immunoglobulin present. The proteins are visualized by staining with acid violet.(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)
Protein, total: Monday through Sunday
Electrophoresis, protein; Immunofixation: 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
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
RMPSU | Monoclonal Protein Study, Random, U | In Process |
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 |
32526 | Immunofixation, Random, U | 74666-9 |
606979 | Immunofixation Flag, Random, U | No LOINC Needed |