Serum Free Light Chains (Kappa and Lambda) Blood Test

This private haematology blood test measures free kappa and free lambda immunoglobulin light chains in serum and calculates the kappa-to-lambda ratio. The catalogue price is £425.00 plus a £50 phlebotomy fee, with results in 5 days.

Serum free light chain analysis is recommended by NICE alongside serum protein electrophoresis when investigating suspected paraproteinaemia, MGUS, myeloma or AL amyloidosis.

Written by Mr Stephen Lingam. Reviewed by Dr Mohammad Bakhtiar (GMC 4694470) on 18/10/2026.

What does a serum free light chains test include?

The report provides quantitative free kappa light chains, free lambda light chains and the calculated kappa/lambda free light chain ratio.

Can kidney function affect serum free light chain levels?

Yes. Because free light chains are cleared by the kidneys, reduced eGFR can raise both kappa and lambda levels while keeping the ratio near the renal reference range.

Do I need to fast before the blood draw?

No fasting is required. You can eat and drink normally before your appointment at 117a Harley Street.

Which tests are commonly ordered alongside serum free light chains?

Haematologists commonly pair serum free light chains with a full blood count, urea and electrolytes, calcium, immunoglobulins and serum protein electrophoresis.