Urinary protein fraction in healthy subjects using cellulose acetate membrane electrophoresis followed by colloidal silver staining

We previously reported a rapid and highly sensitive colloidal silver staining solution suitable for the cellulose acetate membrane. This method was useful for detecting even very small amounts of urinary protein. In the present study, we examined urinary protein fractions in healthy subjects, using cellulose acetate membrane electrophoresis (CAE) with a highly sensitive colloidal silver staining, in an attempt to determine the clinical relevance of urinary protein fractions. Sixty unconcentrated spot urine specimens were analyzed by CAE and calculated by densitometry. All of the samples were separated into five fractions by CAE. The mean±1 SD of the percentage of five fractions was 28.37±8.51 in albumin, 4.30±4.19 in α1-globulin, 14.41±6.14 in α2-globulin, 19.45±7.10 in β-globulin, and 33.46±8.24 in γ-globulin. The albumin/globulin (A/G) ratio was 0.41±0.17. These six items and the concentrations of total protein, albumin, and β-N-acetyl-D-glucosaminidase (NAG) did not significantly differ between males and females. NAG is the marker of tubulointerstitial nephropathy. The results suggest that there are no gender-dependent differences in the urinary protein fractions of healthy subjects. J. Clin. Lab. Anal. 18:231–236, 2004. © 2004 Wiley-Liss, Inc.