Pathologic versus physiologic cholestasis: elevated serum concentration of a secondary bile acid in the presence of hepatobiliary disease.

Serum levels of the primary bile acids cholic and chenodeoxycholic acid are transiently elevated in normal neonates and infants; this represents a state of "physiologic cholestasis." In this study we determined, using specific radioimmunoassay, the concentration of a secondary bile acid, sulfated lithocholate, in serum obtained from healthy infants and from those with various hepatobiliary diseases. The serum levels of sulfated lithocholate were low in 69 neonates (less than 5 days of age: mean +/- SEM = 0.45 +/- 0.05 mumoles/L) and in 78 normal infants (less than one year of age: 0.49 +/- 0.02); there was no postprandial rise. These values were similar to those seen in 95 older children (0.56 +/- 0.03) and in maternal (0.49 +/- 0.04) and cord blood (0.44 +/- 0.03) of the neonates. In contrast, in patients with neonatal cholestasis of any nature there was a consistent marked rise in serum concentrations of sulfated lithocholate (mean = 4.46 +/- 0.39, P less than 0.001). In infants monitored during the course of parenteral nutrition, elevated values of sulfated lithocholate often occurred in the presence of normal results of other liver function tests. Serum sulfated lithocholate concentration is an accurate index of neonatal hepatobiliary disease; the sensitivity and specificity of this test remain to be further defined.