serum free light chains

Introduction

serum free light chains assays are used in conjunction with serum electrophoresis in the investigation and monitoring of blood dyscrasias such as multiple myeloma

In general, significantly increased free light chain production and an abnormal kappa/lambda ratio indicate a poorer prognosis and an increased risk of disease progression.
When the test is used to monitor a known light chain plasma cell disorder, then a decrease in the quantity of excess light chain and a more normal kappa/lambda ratio indicates a response to treatment.

“Normal”:
- Free light chains will normally be present in the blood at low levels, but with a normal kappa/lambda ratio.
Increased light chains with NORMAL kappa/lambda ratio
- may occur in:
  - renal disease
  - connective tissue (CT) disorders
  - inflammatory conditions
  - neurological conditions
  - some cancers
Decreased light chains with NORMAL kappa/lambda ratio
- may occur in:
  - bone marrow cell production suppression disorders
Increased kappa free light chains and an increased kappa/lambda ratio
- may be seen with plasma cell disorders that produce excess monoclonal kappa light chains
Increased lambda free light chains and a decreased kappa/lambda ratio
- may be seen with plasma cell disorders that produce excess monoclonal lambda light chains