[Significance, sources of error and limits of protein diagnosis in urine. II. Normal values and classification of pathologic proteinurias].

Physiological excretion of total protein in the urine of newborns, infants, children and adults is below 150 mg/d/1.73 m2. Albuminuria is below 25 mg/d/1.73 m2 and excretion of beta 2-microglobulin below 0.4 mg/d/1.73 m2. Fever, exercise and orthostasis may cause a reversible increase of protein excretion. The significance of isolated and persistent proteinuria remains obscure. Polyacrylamide gel techniques differentiate between pathological high or low molecular weight proteinuria and thereby glomerular and tubular disorders.