Abstract

FACIO, María Laura et al. Urinary protein profile and SDS-PAGE tubular pattern evaluation. Acta bioquím. clín. latinoam. [online]. 2006, vol.40, n.3, pp.383-390. ISSN 0325-2957.

Early studies demostrated the clinical potential of SDS-PAGE to evaluate the proteinuria profile, although it has not been widely adopted in the routine laboratory. SDS-PAGE and conventional zone electrophoresis (ZE), both stained with the silver stain procedure were compared with the automated immunoturbidimetry results of a-1microglobulin and b-2microglobulin. One hundred and five unconcentrated 24 hr collection urines sent to our Laboratory for creatinine clearance determination were used. A 72% of the physiologic profile rendered identical interpretations. ZE showed only an albumin band for all samples according to SDS-PAGE in 86.5%, but presented an additional A1m band in 13.5%, whose quantitations were below 12 mg/L. SDS-PAGE classified 14 samples as glomerular, tubular or mixed pattern instead of physiologic (proteinuria values close to 0.2 g/24 hr). The presence of A1m plus another lower MW band in SDS-PAGE correlated with quantitative values upper the normal limit for B2m (p < 0.0001)-sensitivity 86% (CI 95% = 75-93%) specificity 93% (CI 95% = 81-99%). The comparison between this so well defined SDS-PAGE tubular profile and A1m > 12 mg/L-sensitivity 94% (CI 95% = 86-98%)-specificity 97% (CI 95% = 87-100%) was extremely significant (p < 0.0001). Use of SDS-PAGE could potentially enable the assessment of proteinuria and the management of renal patients particularly in tubular damage, with high sensitivity and specificity.

Keywords : sodium dodecyl sulphate - polyacrylamide gel electrophoresis; a1-microglobulin; b2-microglobulin; tubular damage; proteinuria; zone electrophoresis.

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