Serum or Plasma Free Light Chain Immunoglobulin (kappa or lambda) by Immunoassay

Why Is This Test Done?

Your healthcare provider may order this test to investigate symptoms like unexplained fatigue, frequent infections, or bone pain. It can also help diagnose or monitor conditions such as multiple myeloma, lymphoma, or other blood-related disorders. Free light chains are often checked alongside other blood tests to get a full picture of your health.

What Does the Test Measure?

The test detects abnormal levels of free light chains (kappa or lambda) in your blood. These chains are fragments of antibodies produced by plasma cells. When these cells become cancerous (as in multiple myeloma), they may release too many free light chains into the bloodstream, which can be detected by this test.

Sample Collection and Preparation

A blood sample is drawn from a vein in your arm. The blood is then separated into components, and the free light chains are measured using a specialized immunoassay technique. This test is typically done on serum or plasma, depending on the lab’s protocol.

What Are Common Findings?

Normal results mean the free light chains are within expected ranges for healthy individuals. Elevated levels may indicate conditions like multiple myeloma, amyloidosis, or other immune system disorders. Very low levels might suggest immune deficiencies or other rare conditions. Your healthcare provider will interpret results in the context of your overall health and symptoms.