Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (940 page)

   As a screening test for occult alcoholism

   To aid in diagnosis of liver disease in the presence of bone disease, pregnancy, or childhood, which increase serum ALP and LAP but not GGT

   Interpretation

Increased In

   DM, hyperthyroidism, RA, COPD.

   Drugs (phenytoin, carbamazepine, cimetidine, furosemide, heparin, methotrexate, oral contraceptives, and valproic acid).

   Liver disease—generally parallels changes in serum ALP, LAP, and 5′-NT but is more sensitive.

   Acute hepatitis. Elevation is less marked than that of other liver enzymes, but it is the last to return to normal and, therefore, is useful to indicate recovery.

   Chronic active hepatitis; increased (average more than seven times ULN) more than in acute hepatitis; more elevated than AST and ALT. In dormant stage, it may be the only enzyme elevated.

   Alcoholic hepatitis; average increase >3.5 times ULN.

   Alcohol abuse; a GGT/ALP ratio >2.5 is highly suggestive.

   Cirrhosis. In inactive cases, average values are lower (four times ULN) than in chronic hepatitis. Increases of more than 10–20 times normal in cirrhotic patients suggest superimposed primary carcinoma of the liver (average increase >21 times ULN).

   Primary biliary cirrhosis. Elevation is marked: average >13 times ULN.

   Fatty liver; elevation parallels that of AST and ALT but is greater.