Sensitivity and specificity of liver function tests in the detection of parenteral nutrition-associated cholestasis.

We carried out a study to determine which of the liver function tests was the most sensitive and/or specific in detecting parenteral nutrition associated cholestasis. The tests utilized were alkaline phosphatase, gamma-glutamyl transpeptidase, cholylglycine, sulfolithocholylglycine, and bilirubin. Fifty-nine patients with no prior evidence of liver dysfunction were studied. We found gamma-glutamyl transpeptidase to be the most sensitive (89.5%) and also the least specific (61.9% specificity). Specificity of gamma-glutamyl transpeptidase was improved when it was combined with alkaline phosphatase. We recommend the combination of these two enzymes as the most cost effective way of detecting parenteral nutrition-associated cholestasis.