Transaminases AST and ALT are transaminases. They are associated with inflammation and/or injury to liver cells, a condition known as hepatocellular liver injury. Damage to the liver typically results in a leak of AST and ALT into the bloodstream.
AST is found in many other organs besides the liver: kidneys, muscle and the heart, A high level of AST does not always (but often does) indicate that there is a liver problem. E.g. vigorous exercise may elevate AST levels. ALT is found primarily in the liver, high levels of ALT almost always indicate that there’s a problem with the liver. Conversely, a normal ALT level does not necessarily mean that the liver is definitely normal
High levels of transaminases don’t always reveal the level of liver is damage but they are a marker of acute inflammation. These blood tests measure inflammation and damage to the liver at an isolated point in time. Recent inflammation may raise them even if no significant underlying damage conversely even with severe underlying liver damage they may be normal.
The ratio of ALT to AST may also provide useful information - most liver diseases are characterized by greater ALT elevations than AST elevations however there are two main exceptions. Both cirrhosis and/or alcohol abuse are associated with higher AST levels than ALT levels, often in a ratio of approximately 2:1. Elevations of the transaminases occur due to so many causes that they give the only a vague clue of the diagnosis. Additional testing is required in order to determine more precisely what is wrong with the liver.
GGT Gamma Glutamyl Transpeptidease and AP Alkaline Phosphatase High levels of GGT and AP hint at a bile duct problem either blockage or injury or inflammation. This is caused by an impairment, or failure, of bile flow, which is known as cholestasis. This type of liver injury is known as cholestatic and this type of liver disease is known as cholestatic liver disease..
Intrahepatic cholestasis refers to bile duct blockage or injury within the liver. Intrahepatic cholestasis may occur in people with primary biliary cirrhosis, alcoholic damage or liver cancer, for example. Extrahepatic cholestasis refers to bile duct blockage or injury occurring outside the liver. Extrahepatic cholestasis may occur in people with gallstones
When a blockage or inflammation of the bile ducts occurs, the GGT and AP levels increase and raise the blood level. These enzymes typically become markedly elevated— many times the upper limit of normal. GGT is found predominantly in the liver. AP is mainly found in the bones and the liver but can also be found in many other organs,e.g. the intestines, kidneys, and placenta. Elevated levels of AP will usually indicate that something is wrong with the liver only if the amount of GGT is raised as well.
GGT can be elevated without AP being elevated, as GGT is a sensitive marker of alcohol ingestion and certain hepatotoxic drugs.
Normal Values Bilirubin <21 ALT <40 AP female under 60 <104 male and female over 60 <129 Albumin 35-50 GGT female 7-33 male 11-51
30 year old man Complains that after a stag weekend he felt awful and friends said he looked “yellow”
30 year old man Bilirubin 28 ALT 45 GGT42 AP 103 Albumin 42
48 year old woman Separated 6/12 ago Says drinks a bottle wine daily Perhaps more lately Asking for sicknote due to stress Lethargy and retching in morning
48 year old woman Bilirubin 14 ALT 63 AP 189 GGT 385 Albumin 37
61 year old man 20 year history alcohol abuse 3 x alcohol detox in past 10 years Complaining of abdo swelling O/E Distended abdo, no palpable liver Multiple spider naevi
61 year old man Bilirubin 21 ALT 38 AP 120 GGT 43 Albumin 31 What other investigations would be useful?
61 year old man MCV-104 INR 2.3 USS liver- evidence cirrhosis