Alkaline phosphatase
Background
- Enzyme found in liver (biliary), bone, intestine, and placenta
- Elevated in cholestatic/obstructive liver disease and bone disorders
Normal Values
- Normal: 44-147 U/L (varies by age; higher in children and adolescents)
Interpretation
- Elevated with GGT: suggests hepatobiliary source (cholestasis, biliary obstruction, infiltrative liver disease)
- Elevated without GGT: suggests bone source (fractures, Paget disease, bone metastases, growth in children)
- Markedly elevated (>3x): biliary obstruction, primary biliary cholangitis, drug reaction
- Isolated mild elevation in an asymptomatic patient is often benign