Liver function tests
Background
A liver function test is a group of blood tests that, when evaluated as a whole, allow the clinician to determine if there is any damage to the liver, determine if that damage is acute or chronic, and determine if there is hepatobiliary stasis for any reason. The essential components of an LFT includes liver transaminases (AST, ALT), which are surrogates markers of liver health, coagulation studies (PT, PTT, INR), albumin, total protein, lactate dehydrogenase, and liver enzymes GGT and Alkaline Phosphatase which, in conjunction with direct and total bilirubin, are surrogate markers of biliary patency and function.
Normal Values
ALT: 7 - 55 U/L AST: 8 - 48 U/L Alk Phos: 45 - 115 U/L Albumin: 3.5 to 5.0 g/dL Total protein: 6.3 - 7.9 g/dL Bilirubin: 0.1 - 1.2 mg/dL GGT: 9 - 48 U/L LD: 122 - 222 U/L PT: 11 - 14 seconds PTT: 25 - 35 seconds INR: 0.8 - 1.2