Diagnosis of Liver Disease
Diagnosis of liver disease usually begins with a medical history and physical examination. The physician often asks questions about the onset and severity of symptoms. During the physical exam, the physician often presses gently on the patient's abdomen to feel for enlargement of the liver and spleen.
If liver disease is suspected, a blood test called a liver panel (also called a liver function test or liver enzyme test) usually is performed. These tests measure levels of certain proteins and enzymes in the blood to determine how well the liver is functioning.
Liver function tests include checking levels of the following substances in the blood:
- ALT (alanine aminotransferase)
- ALP (alkaline phosphatase)
- AST (aspartate aminotranferase)
- Bilirubin (2 different tests: total bilirubin or direct bilirubin)
- GGT (gamma glutamyltranspeptidase)
- LDH (lactic acid dehydrogenase)
- Platelet count
- PT (prothrombin time) or INR (international normalized ratio)
- Serum protein electrophoresis or total protein
In many cases, specific symptoms help determine exactly which tests are performed. For example, if hepatitis A is suspected, the physician may order tests for bilirubin, ALT, and AST.
Diagnosing hepatitis B and C involves additional blood tests for specific antibodies. Other blood tests for hepatitis B can help determine if the patient is contagious and whether the infection is chronic. Additional tests for Hepatitis C can detect which of 6 known strains of the virus are present. This information can help determine the best options for treatment.
Imaging tests (e.g., ultrasound, CT scan, MRI scan, x-rays) may be performed to determine if, and to what extent, the liver has been damaged.
Liver function is affected by the other components of the biliary tract (i.e., the bile duct [small tube that carries bile from the liver to the small intestine], gallbladder, and pancreas). If the physician suspects that a disease of the biliary tract (e.g., gallstones) is causing a liver problem, an examination called an endoscopic retrograde cholangiopancreatography (ERCP) may be performed.
ERCP, which is performed under local anesthesia and sedation, involves passing a special device that contains a tiny light and camera (called an endoscope) through the throat, esophagus, stomach, and into the first part of the small intestine (duodenum). Once the endoscope reaches the biliary tree and pancreas, a contrast dye is injected into the bile ducts and a series of x-rays is taken. The contrast dye allows the bile ducts, gallbladder, pancreas, and liver to show up more clearly in the x-rays.
In some cases, a liver biopsy also may be performed. Liver biopsy involves surgically removing a small sample of liver tissue for microscopic evaluation.
Depending on the symptoms and initial diagnosis, patients who have liver disease often are referred to a medical specialist (e.g., gastroenterologist, hepatologist). In some cases, the patient also may be referred to an infectious disease specialist who has extensive experience with hepatitis B and C patients.