False-negative urine protein electrophoresis by semiautomated gel electrophoresis.

Abstract

Urine is evaluated by electrophoretic methods both to gather information about the location and degree of damage within the nephron and to detect and quantify monoclonal free light chains (Bence Jones proteins). For many years, urine protein electrophoresis consisted of concentrating the urine (usually >50-fold) followed by manual application of the concentrated sample to a gel. Recently, semiautomated methods have become available that allow for a more efficient application of urine to the gels. The Sebia Hydragel β1-β2 15/30 (Sebia, Inc.) method provides urine gel results with crisp separation of β1-β2 as recommended by the guidelines for clinical and laboratory evaluation of patients with monoclonal gammopathies (1). However, in a recent urine sample, despite the presence of 2288 mg/24 h of total protein, the urine protein electrophoresis gel failed to demonstrate the proteinuria although the urine had been concentrated 50-fold (Fig. 1A⇓ ). The technologist had observed sediment in the concentrated urine specimen. Because of …