From the Guidelines
A high kappa/lambda ratio in blood or urine typically indicates a monoclonal gammopathy, which means there is an excess production of one type of immunoglobulin light chain (kappa) compared to the other (lambda). This finding is most commonly associated with plasma cell disorders such as multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS), or other lymphoproliferative disorders. The normal kappa/lambda ratio in serum is approximately 0.26-1.65, and values above this range suggest clonal proliferation of plasma cells producing kappa light chains. This abnormal ratio occurs because cancerous or abnormal plasma cells typically produce only one type of light chain rather than a balanced mixture.
When evaluating a high kappa/lambda ratio, further testing is usually necessary, including:
- Serum protein electrophoresis
- Immunofixation
- Bone marrow biopsy
- Imaging studies to determine the underlying cause and extent of disease. The significance of an elevated ratio depends on clinical context and should be interpreted alongside other laboratory findings and symptoms such as bone pain, anemia, renal dysfunction, hypercalcemia, or recurrent infections 1.
It is essential to consider the clinical context and other laboratory findings when interpreting the kappa/lambda ratio, as an abnormal ratio can be associated with various conditions, including multiple myeloma, MGUS, and other lymphoproliferative disorders 1.
In patients with a high kappa/lambda ratio, the International Myeloma Working Group recommends further evaluation, including bone marrow aspiration and biopsy, to determine the presence of clonal plasma cells and to assess the extent of disease 1.
Overall, a high kappa/lambda ratio is a significant finding that requires further evaluation and interpretation in the context of the patient's clinical presentation and other laboratory results.
From the Research
Kappa/Lambda Ratio
- A high kappa/lambda ratio is an indicator of clonality in plasma cells, which can be a sign of multiple myeloma 2.
- The kappa/lambda ratio is used in bone marrow immunohistochemistry to diagnose multiple myeloma, with a ratio of ≤1/7 or ≥9 considered to have the highest diagnostic accuracy 2.
- A high kappa/lambda ratio can indicate the presence of a clonal plasma cell population, which is a characteristic of multiple myeloma 3, 4.
Diagnostic Criteria
- The diagnosis of multiple myeloma requires the presence of clonal bone marrow plasma cells, as well as evidence of one or more multiple myeloma defining events, such as hypercalcemia, renal failure, anemia, or lytic bone lesions 3, 4.
- The kappa/lambda ratio is one of the diagnostic criteria used to identify clonality in plasma cells, along with other tests such as serum protein electrophoresis and bone marrow biopsy 5, 6.
Interpretation of Results
- A high kappa/lambda ratio should be interpreted in the context of other diagnostic tests and clinical findings, as it can be a sign of multiple myeloma or other plasma cell disorders 2, 3, 4.
- The results of the kappa/lambda ratio test should be correlated with other laboratory tests, such as serum protein electrophoresis, and clinical findings, such as bone marrow biopsy results, to confirm the diagnosis of multiple myeloma 5, 6.