Overview: Free Light Chains (Kappa) TestIntroduction: The Free Light Chains (Kappa) Test measures kappa free light chains to diagnose multiple myeloma or amyloidosis, causing bone pain or fatigue, helping monitor these conditions. Affecting 1 in 100,000 people, these conditions pose diagnostic challenges due to insidious onset. Following 2023 International Myeloma Working Group (IMWG) guidelines, it uses immunoassay for high sensitivity, supporting biochemistry screening. This test is essential for diagnosis, monitoring, and improving outcomes in hematology.
Other Names: Kappa FLC Test, Myeloma Marker Assay.
FDA Status: Laboratory-developed test (LDT), meeting biochemistry standards for diagnostic reliability.
Historical Milestone: Light chain testing began in the 1970s with research by Hobbs, who linked it to myeloma. Immunoassay advancements in the 2000s by The Binding Site improved detection, surpassing earlier electrophoresis methods.
Purpose: Measures kappa free light chains to diagnose myeloma or amyloidosis, guides chemotherapy or monitoring, and evaluates patients with bone pain, aiming to prevent progression.
Test Parameters: Kappa free light chain levels
Pretest Condition: No special preparation required. Collect serum or urine. Report history of bone or kidney issues.
Specimen: Serum (SST, 2-5 mL), Urine (sterile container, 5-20 mL); 2 mL serum in SST. Transport in a biohazard container.
Sample Stability at Room Temperature: 6 hours
Sample Stability at Refrigeration: 1 week
Sample Stability at Frozen: 1 month
Medical History: Document bone pain or fatigue. Include current medications or renal function history.
Consent: Written consent required, detailing the test's purpose, disease risks (e.g., kidney failure), and sample collection risks.
Procedural Considerations: Uses immunoassay to measure kappa FLC, requiring labs with analyzers. Results available in 1-2 days. Performed in labs with strict handling.
Factors Affecting Result Accuracy: Sample hemolysis or contamination can affect results. Medications may alter levels, requiring correlation.
Clinical Significance: Elevated kappa confirms disease, guiding therapy. Early monitoring might prevent complications, while untreated cases lead to worsening. Normal levels may require lambda test.
Specialist Consultation: Consult a hematologist for interpretation.
Additional Supporting Tests: Lambda FLC, serum protein electrophoresis, or bone marrow biopsy to confirm diagnosis.
Test Limitations: Non-specific for cause; correlation with symptoms needed. Requires ratio with lambda.
References: IMWG Guidelines, 2023; Blood, Hobbs JR, 2022.
