Diagnostic strategies and test algorithms in liver disease

As clinicians evaluate patients, they first develop problem lists based on the history, physical examination, and basic laboratory studies. Synthesis and analysis result in a differential diagnosis with associated disease probabilities. Experienced clinicians then selectively use diagnostic tests to rule in or rule out these possibilities. For example, in a patient presenting with jaundice, anorexia, fever, and abdominal pain, the relative increases of the serum aminotransferase activity and the serum alkaline phosphatase will help to guide the subsequent evaluation. If the aminotransferase activity is markedly increase, then the subsequent evaluation will be targeted toward identifying an etiology for hepatocellular injury. In contrast, if the alkaline phosphatase is markedly increased, then the evaluation would be targeted toward identifying an etiology for obstructive jaundice. This paper reviews clinical decision making, discusses characteristics of diagnostic tests, and presents examples of how basic clinical information can guide the use of the laboratory in evaluating patients with suspected liver disease.