Liver “function” refers to the liver’s ability to do the tasks stated above. There are several ways in which to measure liver function, the most common is with simple blood tests. These blood tests include liver enzymes that are made by hepatocytes (ALT, AST); an enzyme manufactured by the cells lining the bile ducts (alkaline phophatase); the level of bilirubin in the blood; the level of protein in the blood which is synthesized in the liver (albumin); and a measure of clotting ability (INR). There is a range of normal values for each of the above lab tests and if they are above the normal range, it is referred to as “abnormal liver function tests”. There are an infinite number of reasons why liver function tests may be elevated but the most common are: alcohol, fatty liver (also called “metabolic syndrome”), medications (prescription, illicit and OTC), vitamins/supplements, infection, cholestasis (when bile backs up in the bile ducts).
Since it is not normal to have abnormal liver tests this will prompt further evaluation of the liver with imaging studies such as Abdominal Ultrasound, CT scan or MRI; more detailed bloodwork and possibly a liver biopsy (an outpatient procedure where a small needle is used to take a tiny piece of the liver to view microscopically).