Abnormal definition, not normal, average, typical, or usual; deviating from a standard: abnormal powers of concentration; an abnormal amount of snow; abnormal behavior.

LFTs are not specific to specific systems or disease processes, yet abnormalities may indicate significant or serious disease. Interpreting abnormal LFTs and trying to diagnose any underlying liver disease is a common scenario in Primary Care. Single abnormalities in LFTs are difficult to localise and diagnose [ 2 ] . However, the pattern of abnormalities tests helps determine origin of the issue. This usually means dividing the clinical picture into non-hepatic, hepatocellular and cholestatic patterns of abnormality. When this is then combined with a clinical history, medication and drug history and the presence of any current or recent symptoms, it is usually possible to develop a differential diagnosis [ 1 , 3 ] .