[Rational laboratory diagnosis of cholestasis syndrome]

Laboratory diagnostics efficiently applied is of decisive importance for a great deal of questions in spite of the technical and endoscopic methods which are available today in the field of examinations. By means of a screening programme consisting of ALAT, gamma-GT, ChE at a sensitivity of > 90% alterations in both the hepatobiliary system and cholestasis can be recognized with sufficient reliability. Clinical data and a defined laboratory routine programme as a second step in diagnostics results in reliable indication for distinction between obstructive and non-obstructive cholestasis which can be promoted by computer-aided techniques. On the basis of such pre-selections special laboratory methods (differential diagnosis of consecutive non-obstructive cholestasis in liver diseases) or invasive methods to clarify their reason and localization diagnostics of biliary obstruction can then be applied in a well-directed manner to obtain a definite nosologic diagnosis. Effective diagnostic procedures in this three-step programme are described.