Overview: Free Light Chains (Lambda) TestIntroduction: The Free Light Chains (Lambda) Test measures lambda free light chains to diagnose multiple myeloma or amyloidosis, helping identify causes of bone pain or kidney issues. 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 vital for diagnosis, monitoring, and improving outcomes in hematology.
Other Names: Lambda FLC Test, Amyloidosis 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 lambda free light chains to diagnose myeloma or amyloidosis, guides chemotherapy or monitoring, and evaluates patients with kidney issues, aiming to prevent progression.
Test Parameters: Lambda 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 kidney issues. 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 lambda 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 lambda confirms disease, guiding therapy. Early monitoring might prevent complications, while untreated cases lead to worsening. Normal levels may require kappa test.
Specialist Consultation: Consult a hematologist for interpretation.
Additional Supporting Tests: Kappa FLC, serum protein electrophoresis, or bone marrow biopsy to confirm diagnosis.
Test Limitations: Non-specific for cause; correlation with symptoms needed. Requires ratio with kappa.
References: IMWG Guidelines, 2023; Blood, Hobbs JR, 2022.
