Serum or Plasma Free Light Chain Immunoassay (Quantitative)

Why This Test Matters

Free light chains are part of antibodies produced by plasma cells, which are white blood cells involved in fighting infections. When these cells become abnormal (e.g., in multiple myeloma or other blood disorders), they may release excess free light chains into the bloodstream. This test helps identify elevated levels that may signal underlying conditions requiring further evaluation.

How the Test Works

Your blood sample is analyzed using an immunoassay method to detect and quantify the specific free light chains (kappa and lambda). The results are reported separately for each type, though some labs may provide a combined ratio.

Sample Collection and Preparation

This test typically uses serum (blood without clotting factors) or plasma (blood with clotting factors). Your healthcare provider will collect a blood sample, usually from a vein in your arm, and send it to a lab for testing.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications or foods that could interfere with results. If you have a history of bleeding disorders or are on blood thinners, let your provider know.