[Renal tubulopathy in newborn infants following perinatal asphyxia. Detection by determining beta-2-microglobulin in the urine].

An increased urinary excretion of the low molecular weight protein Beta-2-Microglobulin (B-MG) is a sensitive indicator of renal tubular dysfunction. The B-MG concentration of the first, spontaneously after birth voided urine was determined by the technique of counterimmunoelectrophoresis (CIE) in 26 asphyxiated newborns (Apgar score less than or equal to 5 after 1 min). In 10 patients (38%) there was a positive reaction, in 45 control children with Apgar scores greater than or equal to 7 after 1 min only one positive reaction occurred. Within the measuring range of CIE, urinary detection of B-MG can be an early indicator of renal tubular dysfunction.