Clinical enzymology 2. Test strategies and interpretation of results

The greatest usefulness of enzyme determinations is in diagnosis and management of hepatic, cardiac, pancreatic, and skeletal muscle diseases. They occasionally are useful in patients with malignant or hematologic conditions. As a rule, enzyme determinations are sensitive enough for normal values to exclude disease but are too nonspecific for abnormal values to confirm disease. Exceptions to this rule are determination of the MB isoenzyme of creatine kinase, the flipped lactate dehydrogenase isoenzyme pattern, and calculation of the ratio of amylase clearance to creatinine clearance.