From the Guidelines
The kappa/lambda ratio is a crucial diagnostic and monitoring tool in multiple myeloma, with a normal serum free light chain ratio ranging from 0.26 to 1.65, as defined by the International Myeloma Working Group (IMWG) criteria 1.
Importance of Kappa/Lambda Ratio
The kappa/lambda ratio is essential for diagnosing and monitoring multiple myeloma, as it helps identify the type of light chain produced by the malignant plasma cells.
- An abnormal ratio, either elevated kappa chains (ratio >1.65) or elevated lambda chains (ratio <0.26), suggests a monoclonal process.
- This ratio is particularly useful for diagnosing light chain myeloma, monitoring disease progression, and assessing treatment response.
- An increasingly abnormal ratio often indicates disease progression, while normalization suggests effective treatment.
Clinical Application
The kappa/lambda ratio provides greater sensitivity than traditional protein electrophoresis, especially for detecting early relapse or residual disease 1.
- Regular monitoring of the kappa/lambda ratio, alongside other markers like M-protein levels and bone marrow assessments, helps guide treatment decisions and evaluate remission status in multiple myeloma patients.
- The IMWG criteria emphasize the importance of the kappa/lambda ratio in defining complete response (CR) and stringent complete response (sCR) in multiple myeloma patients 1.
- A normal FLC ratio is required for CR, and an abnormal ratio may indicate residual disease or relapse.
Monitoring and Treatment
In clinical practice, the kappa/lambda ratio is used to monitor disease progression and response to treatment.
- An increasingly abnormal ratio may prompt further investigation or treatment intensification.
- Normalization of the kappa/lambda ratio is a desirable outcome, indicating effective treatment and potential remission.
- The ratio is also useful in detecting early relapse or residual disease, allowing for timely intervention and improved patient outcomes.
From the Research
Kappa Lambda Ratio in Multiple Myeloma
- The kappa/lambda ratio is used to diagnose multiple myeloma, with cut-offs of ≤1/7 or ≥9 yielding the highest diagnostic accuracy 2.
- A study found that a kappa/lambda ratio of ≤1/16 or ≥16 had a lower diagnostic accuracy, with an area under the receiver operating characteristic curve of 0.9643, compared to 1.0000 for the ≤1/7 or ≥9 cut-offs 2.
- The kappa/lambda ratio is calculated by dividing the number of kappa-positive plasma cells by the number of lambda-positive plasma cells in the bone marrow 3.
- A kappa/lambda ratio outside the normal range can indicate the presence of a clonal plasma cell neoplasm, such as multiple myeloma 3.
- The diagnosis of multiple myeloma also involves other tests, including serum protein electrophoresis, urine protein electrophoresis, and imaging studies 4.
Diagnostic Criteria
- The diagnosis of multiple myeloma requires the presence of clonal plasma cells in the bone marrow, as well as one or more of the following:
- High levels of monoclonal protein in the blood or urine
- Hypercalcemia
- Anemia
- Lytic bone lesions 4
- The Revised International Staging System is used to classify multiple myeloma into different stages, based on factors such as serum beta-2 microglobulin and albumin levels, and the presence of certain genetic abnormalities 4.
Treatment and Prognosis
- The treatment of multiple myeloma typically involves a combination of chemotherapy, immunomodulatory agents, and stem cell transplantation 4.
- The prognosis for multiple myeloma varies depending on the stage and other factors, with a median survival of around 5 years for patients with standard-risk disease 4.
- Extramedullary involvement, such as liver involvement, is a poor prognostic factor and requires aggressive treatment 5.