Blood Test Guide

Alkaline Phosphatase (ALP) Test

ALP is an enzyme found in the liver, bones, kidneys and intestine. Elevated ALP points to liver or bone disease. Here's how to interpret your result.

ALP reference ranges

GroupNormal Range
Adults44–147 IU/L
Children / adolescentsUp to 500 IU/L (bone growth)
Pregnancy (3rd trimester)Up to 3x normal (placental ALP)

What does high ALP mean?

Liver vs bone origin

ALP comes from both liver and bone. Raised ALP with raised GGT points to a liver or bile duct cause (cholestasis, bile duct obstruction, primary biliary cholangitis). Raised ALP with normal GGT points to a bone cause — Paget's disease, bone metastases, healing fractures, or hyperparathyroidism. In children, ALP is naturally high during growth spurts and is not a cause for concern.

Causes of raised ALP

CauseCategory
Bile duct obstruction (gallstones, cancer)Liver/biliary
Primary biliary cholangitis (PBC)Liver/biliary
Paget's disease of boneBone
Bone metastasesBone
HyperparathyroidismBone
Healing fracturesBone
Pregnancy (3rd trimester)Physiological

Questions to ask your doctor

Medical Disclaimer: For educational purposes only. Always consult a qualified healthcare professional for diagnosis and treatment.