Evaluation of three methods of protein analysis for serum and heart homogenates.

: The Biuret, Ultraviolet and Lowry techniques for the determination of total protein content were compared in 31 samples of patient serum and in 30 rat heart tissue homogenates. Statistically significant differences were found to exist between values obtained with each method. Human serum and heart homogenate protein were both lowest when assayed by the Lowry procedure, while serum and homogenate values were highest with the Ultraviolet and Biuret method, respectively. Possible sources of these discrepancies are discussed. Although the Biuret method may not be as sensitive as the other two methods, it proved to be the most reproducible technique for determining total protein concentration in the particular types of samples used in this study.