Interpreting complex urinary patterns with MDI LABLINK: a statistical evaluation

The measurement of urinary marker proteins is not a generally accepted labo ratory practice because the results are difficult to interpret. MDI-LABLINK is software for classifying patterns of specific urinary marker proteins. The interpretations are completely user definable thanks to a specific 'pat tern definition database'. Our interpretation set is based on Hofmann and G uder's work in measuring and interpreting single urinary proteins. We inclu de additional marker proteins in order to adapt Boesken's SDS-PAGE classifi cation. During the last 3 years, 1905 patterns were fully differentiated an d identically interpreted. Firstly, the samples were classified into three patterns: normal (25.8%), predominantly glomerular (27.2%, selective, unsel ective, mixed, and with additional tubular proteins) and predominantly tubu lar (36.9%, complete/incomplete form, with additional glomerular proteins); 8.9% showed postrenal proteinuria. Secondly, glomerular selectivity measur ed by using urinary transferrin/IgG ratio alone correlates well with the es tablished SI index (the ratio between IgG and transferrin clearances). Thir dly, the creatinine concentration substantiates the validity of the sample. The quality of the preanalytical phase can be improved through the ongoing education of the medical staff. Finally, measurement of urinary albumin an d alpha-1-microglobulin is mandatory where kidney disease is suspected, has to be ruled out, or requires close monitoring, even when the total protein concentration is normal. (C) 2000 Elsevier Science B.V. All rights reserve d.