Evaluating the use of unconcentrated urine for protein electrophoresis and immunofixation: An alternative approach...

Protein electrophoresis is a widely used technique for separating and analyzing proteins based on their charge and size. Traditionally, concentrated urine samples have been employed to enhance protein detection sensitivity, but this method can be time-consuming. In contrast, using unconcentrated urine offers a more efficient and resource-friendly alternative for streamlining the analytical process. This study explores the feasibility of using unconcentrated urine as an alternative sample type for protein electrophoresis (UEL) and immunofixation (UIFE).

Both UEL and UIFE were performed on 80 routinely ordered urine specimens (either random or 24-h collections) for patient management. The analyses were carried out on both concentrated (X40) using Sebia gels and unconcentrated (neat) samples using HYDRAGEL 9IF gels with the HYDRAGEL BJ dynamic mask procedure. The electrophoretic patterns obtained from unconcentrated urine were compared with those from concentrated urine. Various electrophoretic parameters, including resolution, sensitivity, and reproducibility, were evaluated to assess the reliability of using unconcentrated urine for protein electrophoresis. Additionally, a retrospective analysis was conducted on all urine specimens ordered before and after the implementation of the new method to identify any differences in monoclonal band distributions within the population.

The protein concentrations showed a strong correlation, with 95-100 % agreement between the two methods and clear separation of protein fractions. Serial dilution studies of monoclonal band analyses demonstrated that these bands could be detected at concentrations of 10-20 mg/L using the unconcentrated method. Furthermore, the retrospective analysis of patient data before and after implementing the new method revealed no differences in the identification or types of monoclonal proteins.

These results indicate that unconcentrated urine can be successfully used for UEL and UIFE, yielding outcomes comparable to those obtained with traditional concentrated samples. Utilizing unconcentrated urine simplifies the sample preparation process and presents a promising alternative for protein analysis.