Serum or Plasma Free Light Chain Kappa (Mass Concentration)

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like unexplained fatigue, frequent infections, bone pain, or kidney problems. It’s also used to monitor certain blood cancers or autoimmune diseases. Sometimes, doctors check it when other blood tests show abnormal results.

What to Expect Before the Test

No special preparation is needed. You’ll likely have blood drawn from a vein in your arm. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results are compared to a general range for healthy adults. High levels may indicate conditions like multiple myeloma, lymphoma, or other plasma cell disorders. Low levels alone usually don’t signal a problem unless combined with other symptoms or test results.

Common Conditions Linked to Results

Elevated free light chains are often linked to plasma cell disorders, such as multiple myeloma, where abnormal plasma cells produce too many light chains. They can also appear in other cancers (e.g., lymphoma) or inflammatory diseases. Kidney disease may also affect how these proteins are processed in your body.