Liver Function Tests (LFTs)

These tests show us if anything is happening in the liver, though they do not tell us what the cause is.ย  The following also appear on a general lab test Comprehensive Metabolic Panel (CMP):

**ย  ALT and AST:ย  Liver enzymes, also called transaminases.ย  “Normal” is usually <40 or <60 IU/L, depending on the lab (although liver specialists say it should be <30 in men and <25 in women).ย  The degree of elevation depends on the illness.ย  Some general averages:

  • Acute Hepatitis (A,B,C,D,E):  Usually  >1,000 (I’ve seen 10,000 in Hep A, even though the illness is mild).  See Types of Hepatitis for descriptions of these diseases.
  • Acute Alcoholic Hepatitis (severe damage):  Only 200 – 300, AST higher than ALT
  • Mononucleosis:  Around 100
  • Chronic Liver Diseases (Hepatitis B or C, overload of copper or iron, alcoholism, autoimmune hepatitis, etc:):  Any level, rarely >200, may even be normal
  • NOTE:  To evaluate acute liver failure, must order “Prothrombin Time” separately (requires a different type of test tube to draw the blood)

**  Alkaline Phosphatase:  Elevated in liver disease, but especially in gallbladder disease.  Also can be elevated due to certain bone diseases (e.g. cancer), and pregnancy

**  Bilirubin:  High levels make us jaundiced (eyes & even skin turn yellow).  Can be due to any liver disease, very serious if due to the gallbladder.  Pancreatic cancer.  Also hemolysis (red blood cells break apart for various reasons, nothing to do with the liver).  Some people have genetically high bilirubin, called Gilbert’s Syndrome (pronounced as in French), which is harmless.

**  Albumin:  A protein made by the liver.  If someone with chronic liver disease develops a low albumin, they likely have liver failure (cirrhosis).

**  GGT:  A transaminase like ALT & AST (above).  Not included on the routine CMP.  High levels don’t tell us much, since there are lots of false-positives.  Normal levels reassure us there’s nothing happening in the liver.

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