Diagnostic use of serum alkaline phosphatase isoenzymes and 5-nucleotidase

1. 1. Serum 5-nucleotidase and alkaline phosphatase isoenzymes separated on polyacrylamide gel have been examined in 114 patients with raised total alkaline phosphatase. 2. 2. The isoenzymes gave a good indication of clinical diagnosis of liver and bone disease, with 20% showing multiple bands of more than one origin. 3. 3. 5-Nucleotidase was raised in most but not all patients with hepatobiliary disorders. It is therefore a reasonably specific test of liver disease, but as it is not very sensitive, a normal 5-nucleotidase (with raised alkaline phosphatase) does not exclude this diagnosis, and does not necessarily indicate bone as the origin of the raised alkaline phosphatase. 4. 4. Polyacrylamide gel electrophoresis of alkaline phosphatase isoenzymes is of particular value in cases where there is some difficulty in clinical diagnosis, or where the alkaline phosphatase is high with otherwise normal liver function tests and 5-nucleotidase.