![]() Department of Molecular Biosciences, The University of Texas at Austin, United States.Additional diagnostic tests that may be helpful in confirming a diagnosis of multiple myeloma include serum protein electrophoresis to evaluate for monoclonal or biclonal gammopathy, radiography to evaluate for osteolytic lesions, and bone marrow cytology to evaluate for plasmacytosis (Figure 1). The most common problem reported with immunofixation electrophoresis is that it also detects intact immunoglobulins in the urine that are unassociated with Bence-Jones protein. Immunofixation electrophoresis distinguishes between kappa and lambda light chains and identifies the heavy chains of IgA, IgM, and IgG. Light chain concentration below limit of detection of the assayĪ positive Bence-Jones protein result on urine electrophoresis can be confirmed and further characterized by more sensitive and specific techniques such as immunoelectrophoresis and immunofixation electrophoresis.Hemoglobin interference from (hemorrhage or hemolysis).Chronic lymphoplasmacytic inflammation (rare).Other B cell derived neoplasms such as chronic lymphocytic leukemia.Causes of Negative and Positive Bence-Jones Test Results Positive Result Causes of abnormal test results are presented in Table 1. It is important to remember that a negative test result does not exclude a diagnosis of multiple myeloma or B cell neoplasia and a positive result requires additional confirmatory testing. The sample is stable at refrigerator temperature (2-8✬) for approximately one week or can be stored frozen at -18✬ for up to one month.Ī positive test result will appear as a monoclonal spike in the β or γ protein regions on urine protein electrophoresis. The urine sample should be kept refrigerated prior to shipping since the proteins are only stable for approximately 2 hours at ambient temperature. Remember to include the method of collection and date/time of collection on the submission form. An early morning urine collection is ideal. Cystocentesis is the preferred collection method, although catheterized samples and clean free catch are considered acceptable. Twenty-four hour urine collection is ideal, but impractical in most practices. Submit 10 ml of urine in a sterile leak proof container or red top (serum) tube on ice packs to the testing laboratory. Sample Requirements for Urine Protein Electrophoresis The screening test most commonly used is urine protein electrophoresis. Detection of Bence-Jones proteinuria requires sophisticated tests such as urine protein electrophoresis, immunoelectrophoresis, and immunofixation electrophoresis. Laboratory Tests for Bence-Jones Proteinsīence-Jones proteins are not detectable via urine protein dipsticks. A diagnosis of multiple myeloma cannot be excluded based on a negative Bence-Jones protein result for the following reasons: 1) secretion may be intermittent or the concentration too low to be detected in a single urine sample, 2) myeloma cells may be secreting intact immunoglobulin molecules rather than free light chains, and 3) non-secretory types of multiple myeloma (rare) do not produce Bence-Jones proteinuria. More than 50% of dogs and cats with multiple myeloma may have light chain proteinuria. Demonstration of Bence-Jones proteinuria.Demonstration of monoclonal or biclonal gammopathy with serum electrophoresis.>20% plasma cells in bone marrow aspirates or biopsy specimens (Figure 1).Radiographic evidence of osteolytic bone lesions.Two of the 4 following criteria are generally required for diagnosis of multiple myeloma: Bence-Jones proteins were named after the English physician Henry Bence Jones, who described their ability to precipitate when urine is heated to 45-70☌, then redissolve when urine is further heated to near boiling.Ĭonsiderations for Diagnosis of Multiple Myeloma ![]() Because of their small size (MW=22,000-44,000), Bence-Jones proteins can readily pass from the blood through the normal glomerular fenestrations of the kidney into the urine. Multiple myeloma is a clonal proliferation of malignant plasma cells, typically arising in the bone marrow, that produce an immunoglobulin or component of immunoglobulin. Multiple myeloma and some extramedullary plasma cell tumors and chronic B cell lymphocytic leukemia can produce Bence-Jones proteinuria. The specific immunoglobulin component is unassociated kappa or lambda light chains. Veterinary Clinic for Low Income Pet Ownersīy Patty Ewing, DVM, MS, DACVP (Anatomic and Clinical 541-5014īence-Jones proteins, also referred to as M-proteins, myelomas proteins, paraproteins, and free immunoglobulin light chains, are a component of immunoglobulin produced in excess by B cell-derived clonal cell populations.Vet Services Report Cruelty Animal Advocacy Adopt
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