Laboratory investigation of paraproteinaemia.

Abstract

Urine samples with a total protein concentration of lg/l or more should be examined directly. All other samples should be concentrated up to 300-fold as necessary. Adequate concentration is achieved when at least some protein is visible on electrophoresis. Concentration techniques based on ultrafiltration are recommended. Semipermeable membranes should have a molecular exclusion below 20 kilodaltons. We prefer cellulose nitrate collodion thimbles (SM 132 00, Sartorius, Belmont, Surrey) as there is high recovery (> 85%) of Bence-Jones protein monomer. The urine 776 on July 17,