A case of proteinuria with analbuminuria

A 46-year-old black man with diabetes mellitus and hypertension was hospitalized because of myocardial ischemia and chronic renal failure. The electrophoretogram for protein in urine revealed proteins only in the alpha 1, alpha 2, and beta regions. These protein fractions were identified as small molecules by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. No albumin was detected in the urine. The molecular mass of albumin, the protein present in highest concentration in serum, is near the glomerular filtration threshold, and this protein is not reabsorbed by renal tubules; therefore, albumin is consistently present in proteinuric specimens. Thus this analbuminuric pattern is highly unusual. Although the mechanism of the analbuminuria in this case is not fully understood, we wished to document this extremely rare electrophoretic pattern to alert clinical chemists and pathologists of its existence.