Ostase (Bone-specific alkaline phosphatase)

Ostase is an isoenzyme of alkaline phosphatase (ALP) that is specific to bone-forming cells (osteoblasts). The laboratory value measures the concentration of Ostase in the blood and is used to assess bone metabolism.

A test for bone metabolism is recommended for: • Patients with suspected osteoporosis or other bone metabolism disorders • Monitoring of patients under osteoporosis therapy (e.g. bisphosphonates) • People with symptoms such as bone pain or repeated fractures • Diagnosis of Paget's disease or other bone diseases • Children with suspected growth disorders

The test serves the diagnosis and monitoring of diseases associated with increased or decreased bone formation. It is also used to evaluate the effectiveness of osteoporosis therapies.

An elevated Ostase value indicates: • Osteoporosis with increased bone resorption • Paget's disease or other bone diseases • Increased bone formation after fractures or growth spurts A low value rarely has clinical significance. Symptoms with elevated values can be: • Bone pain or increased fractures • Deformities in bone diseases such as Paget's

The testing can be carried out at any time of the day and is independent of food intake.

• Ostase is more specific for bone metabolism than total ALP and is particularly suitable for monitoring the course of osteoporosis therapies. • Physiologically elevated values occur in children and adolescents during growth. • Chronic diseases such as liver diseases should be excluded in order to better classify the cause of an elevated ALP value.