Serum or Plasma Free Light Chain Kappa (Immunoassay)

Why This Test Might Be Ordered

Your healthcare provider may order this test to investigate symptoms like unexplained fatigue, bone pain, or kidney issues. It’s also used as part of monitoring for multiple myeloma, lymphoma, or other blood cancers. Sometimes, it’s checked alongside tests for free lambda light chains to assess the balance between the two types of light chains.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results are compared to a reference range for healthy adults. High levels of free kappa light chains can indicate conditions like multiple myeloma, where plasma cells produce too many light chains. Very low levels may suggest other immune system disorders or medications that suppress light chain production.

Common Conditions Linked to Abnormal Results

Elevated free kappa light chains are often linked to plasma cell disorders, such as multiple myeloma or monoclonal gammopathy of undetermined significance (MGUS). They can also appear in other cancers, infections, or autoimmune diseases. Low levels may be seen in conditions affecting plasma cell function or certain medications.