Identifies: Kappa and lambda immunoglobulin light chains, expressed by plasma cells and plasmacytoid lymphocytes. Also expressed, but less reliably detected, on B cells with small amounts of cytoplasm. The ratio of kappa-positive to lambda-positive cells in normal/polyclonal B cell and plasma cell populations typically ranges from 1:1 to 2:1. Marked increases in this ratio suggest kappa light chain-restriction, while marked decreases in the ratio (significantly < 1) suggest lambda light chain-restriction. Light chain restriction is conventionally used as a surrogate for clonality among B cell neoplasms.
Subcellular Localization: Cytoplasmic
CPT Code(s): 88342 or 88341 (reference only; CPTs may vary)
Turnaround Time: Within 1-2 business days of receipt
Schedule: Monday - Friday
• Formalin-fixed, paraffin-embedded (FFPE) tissue block or cell block - OR -
• 1 unstained slide for each test requested plus 3-4 additional unstained slides cut at 4µm