Methodology: CISH

Clinical Significance:
Kappa and lambda immunoglobulin light chains are expressed by plasma cells and plasmacytoid lymphocytes. They are also expressed, but less reliably detected, on B cells with weak cytoplasmic staining. However, immunoglobulin are also a major component of serum, leading to (in many tissue types) high background/non-specific staining which may obscure the detection/observation of light chain restriction among B lineage cells. This non-specific staining also impedes the assessment of light chain skewing in non-neoplastic populations. As all proteins are translated from mRNA, detection of mRNA transcripts can be a useful surrogate for protein expression and therefore in-situ hybridization for kappa and lambda mRNA transcripts can be used to determine the light chain restriction status for plasma cell and plasmacytoid B cell populations. Subcellular Localization: Cytoplasmic

Organ: Blood/Bone Marrow

Disease State: Amyloid Type Analysis

CPT Code(s): 88365 or 88364. The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Turnaround Time: Within 1-2 business days of receipt

Schedule: Monday - Friday

Specimen Requirements:
• 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