The value of combined determination of high molecular mass API and LP-X in the differential diagnosis of intrahepatic and extrahepatic obstruction.

Combined determination of serum lipoprotein-X and electrophoretic separation of high molecular mass (HMr) alkaline phosphatase has been proposed as a marker for the differential diagnosis between intrahepatic cholestasis and extrahepatic obstructive jaundice. Of 32 patients who were known to be lipoprotein-X positive and in whom a definitive diagnosis had been made, 13 had intrahepatic cholestasis and 17 extrahepatic obstruction, and 2 had both intrahepatic and extrahepatic obstruction. The detection of HMr alkaline phosphatase isoenzyme proved to be a sensitive and specific test for detecting liver disease, particularly obstructive liver disease. The diagnostic significance of the combined determination of serum lipoprotein-X to demonstrate or exclude cholestasis and electrophoretic separation of HMr alkaline phosphatase isoenzymes to allow differentiation between intrahepatic cholestasis and extrahepatic obstruction was investigated.