From the Guidelines
Elevated alkaline phosphatase (ALP) levels, also known as hyperphosphatasemia, are primarily caused by liver and bone diseases.
Causes of Hyperphosphatasemia
- Liver diseases:
- Bone diseases:
- Other causes:
- Pregnancy, due to placental production of ALP 1
- Infiltrative liver diseases, such as sarcoidosis, amyloidosis, and hepatic metastases 1
- Ischemic cholangiopathy and choledocholithiasis 1 To determine the origin of elevated ALP levels, gamma-glutamyl transpeptidase (GGT) testing can be used, as GGT is found in the liver and kidneys, but not in bone 1. Fractionating alkaline phosphatase into its liver, bone, and intestinal isoenzyme fractions can also provide additional information on the etiology of ALP elevations 1.
From the Research
Causes of Hyperphosphatasemia
The causes of hyperphosphatasemia, or elevated alkaline phosphatase (ALP) levels, can be varied and include:
- Underlying malignancy, with the most common being infiltrative intrahepatic malignancy, bony metastasis, and both hepatic and bone metastasis 2
- Bone disease, which can account for a significant portion of cases 2, 3, 4
- Unsuspected parenchymal liver disease, which can be a cause of elevated ALP levels, although less common 2
- Non-malignant infiltrative liver disease, which can also contribute to elevated ALP levels 2
- Other disorders, such as benign familial intestinal hyperphosphatasemia (BFIH) and benign transient hyperphosphatasemia, which can cause persistent elevations of ALP without underlying pathology 5, 6
- High bone turnover, particularly in postmenopausal women, which can lead to elevated ALP levels 4
- Certain medications, such as glucocorticoids and anticonvulsants, which can induce increased ALP activity 3
- Physiologic changes, such as those occurring in young animals, pregnant and lactating females, and in association with high fat diets 3