Liver Function Tests Flashcards
ALT / AST
shows injury to hepatocyte
Alkaline Phosphatase
shows injury to cholangiocytes- meaning obstruction to bile flow
Injury to hepatocyte (Hepatocellular)
Viral hepatitis Drugs affecting hepatocytes Alcohol liver disease Non-alcohol liver disease Autoimmune hepatitis Hereditary diseases (hereditary hemochromatosis, Wilson disease)
Obstruction of bile flow
Gallstones in common bile duct
Pancreatic/ hepatic mass
Drugs affecting bile flow
ALT > AST
all hepatocellular conditions
AST > ALT
conditions caused by alcohol
AST > ALT (2:1) with AST in 100-200 u/L
- Alcoholic liver disease
- Review alcohol hx
ALT > AST, with ALT in 1000 u/l
- Acute viral hepatitis (A, B), acute drug induced injury, (acetaminophen >7.5 g/d)
- Hepatitis A, B panel, acetaminophen level
ALT > AST, with ALT in 100s u/l
- Chronic viral hepatitis (B, C), drug-related injury (TB medications, antiepileptic, methotrexate, statins, amiodarone, acetaminophen, amoxicillin-clavulanate), non-alcoholic fatty liver disease, congestive liver disease, autoimmune hepatitis
- Hepatitis B, C panel, autoantibodies (ANA), review medication history (obesity, T2DM, hyperlipidemia)
Alkaline phosphatase (<120 u/L)
Marker of cholestatic injury (intrahepatic and extrahepatic)
Maybe slightly elevated in hepatocellular injury
Requires evaluation of biliary tree ( US-initial test, MRCP is more accurate
Elevated Alkaline Phosphatase - Ductal dilation on imaging - extrahepatic cholestasis
- Choledocholithiasis: sharp pain
2. Pancreatic Cancer: painless/dull pain
Elevated Alkaline Phosphatase - No Ductal dilation on imaging - intrahepatic cholestasis
metastatic disease (colon, prostate)- hepatocellular carcinoma
PT/INR (11-15 sec/1.0)
Most sensitive marker of synthetic function of the liver
Most sensitive marker of acute liver injury
Marker of prognosis
Increase in PT/INR= decrease in the synthetic liver capacity
**ACUTE CHANGES
Albumin (3.5-5.3 g/dl)
**NOT FOR ACUTE CHANGES
Marker of synthetic function of the liver
Decrease in albumin = decrease in the synthetic liver capacity
Albumin is not specific for the liver( decrease in albumin in nephrotic syndrome or malnutrition)
Maybe normal in acute injury
Total bilirubin (0.5 -1.0 mg/dL)
Marker of synthetic function
Indicator of severity of disease
Bilirubin >2mg/dl
Jaundice
Hepatitis A
- Transmission: Fecal oral
- At risk: Traveling to endemic areas (fecal contamination of water, food)
- Only acute form; self-limiting. Fulminant hepatitis is rare
Hepatitis B
- Transmitted by Blood, Unprotected sex, Mother-baby
- At risk: Unprotected sex, IVD users
- Acute and chronic. Chronic in 90% of infected infants and only 5% of infected adults.
Cirrhosis (in 20% of chronically infected 20 years after exposure)
Hepatocellular carcinoma (HCC 2% risk per year)