Serum or Plasma Free Light Chain Kappa (Immunoassay)

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like unexplained fatigue, frequent infections, or unexplained bone pain. It may also be used to monitor conditions like multiple myeloma, lymphoma, or other blood cancers. Sometimes, it’s part of a broader evaluation for kidney disease or other disorders affecting protein balance in your blood.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. If you’re taking blood from your arm, you may feel a slight pinch. If you’re having blood drawn from your hand or wrist, you may need to rest your arm above your head for a few minutes afterward to reduce bruising.

What the Test Results Mean

Results are compared to a range of normal values for healthy adults. Elevated levels of free kappa light chains can indicate conditions like multiple myeloma, where the body produces too many abnormal proteins. Lower levels may be normal or could be due to other factors like certain medications or kidney disease.

Common Conditions Monitored

This test is often used to diagnose or monitor multiple myeloma, a cancer of plasma cells in the bone marrow. It can also help detect other blood disorders, such as Waldenström macroglobulinemia or other monoclonal gammopathies. In some cases, it may be used to assess kidney function or evaluate protein abnormalities in blood.