Diuresis-dependent excretions of low-molecular mass proteins in urine: β₂-microglobulin, lysozyme, and ribonuclease

Abstract

An investigation was carried out into how the low-molecular mass proteins β₂-microglobulin, lysozyme, and ribonuclease were excreted over 8 h after high fluid intake (22 ml/kg of body weight in 15 min). With increasing urine flow rate the amount of lysozyme excreted per hour or per millimole creatinine increased more markedly than that of β₂-microglobulin while at the same time the excretion rate of ribonuclease decreased. The effect of urinary flow upon the excretion rates of the various low-molecular mass proteins has to be considered as a preanalytical factor when these proteins are used as indicators of tubular dysfunction.

Key Words:

• diuresis
• preanalytical
• proteins in urine
• tubular dysfunction