Routine differential diagnosis of proteinurias by capillary electrophoresis

Capillary electrophoresis is a relatively new analytical technique that beg ins to have an impact on both routine and research in clinical laboratories . Recently, a fully automated system has become commercially available (Par agon CZE 2000, Beckman, USA) for the analysis of human serum proteins. Urin e protein analysis, on the other hand, is currently accomplished by electro phoresis of concentrated urine specimens. The method is used to distinguish the glomerular from the tubular proteinuria and for the identification of Bence-Jones proteins. The procedure is labor-intensive and technically dema nding. We developed a technique for the serum capillary electrophoresis ins trument that can also be applied routinely to the differential diagnosis of proteinurias. Overriding the programmed dilution step of the instrument, w e were able to distinguish different types of proteinurias without concentr ation of specimens with a total protein content of 150-200 mg/l as determin ed by sulfosalicylic acid. The different electrophoretic patterns obtained by the capillary electrophoresis system for various specimens correlated we ll with established techniques (Hydragel Proteinurie Kit, Sebia, France). T he method is applicable for routine analysis of urinary proteins. It is rel iable, less expensive and faster than the conventional methods (electrophor etic or immunonephelometric) used today for the differentiation of proteinu rias, and it can be used as a quick screening test.