Bone Alkaline Phosphatase (BAP) - Ostase

The Bone Alkaline Phosphatase (BAP) – Ostase, Serum test measures the level of bone-specific alkaline phosphatase, an enzyme produced by osteoblasts, the cells responsible for building new bone. It is a useful marker of bone formation and bone turnover, helping evaluate conditions that affect bone metabolism. Unlike total alkaline phosphatase, this test specifically reflects bone activity, making it valuable in the assessment and monitoring of metabolic bone disorders alongside other clinical and laboratory findings.

Who should get this test done?

This test may be recommended for individuals who:

●     Have suspected metabolic bone disorders such as osteoporosis, osteomalacia, or Paget’s disease.

●     Are undergoing evaluation for unexplained bone pain or recurrent fractures.

●     Need monitoring of bone formation during treatment for bone-related conditions.

●     Have abnormal calcium, phosphorus, or vitamin D levels requiring further assessment of bone metabolism.

●     Require evaluation of bone health as advised by their healthcare provider.

Why consider this test?

Bones are constantly undergoing a process of breakdown and rebuilding. The Bone Alkaline Phosphatase (BAP) – Ostase test helps assess the bone formation aspect of this process by measuring an enzyme produced by bone-forming cells. It provides valuable information about bone metabolism, supports the evaluation of various bone disorders, and helps healthcare providers monitor changes in bone activity over time. When used with other bone health tests, it contributes to a more comprehensive understanding of skeletal health.

More information

Bone-specific alkaline phosphatase is one of the most widely used biochemical markers of bone formation. Because it originates primarily from osteoblasts, it offers greater specificity for bone metabolism than total alkaline phosphatase. The test is often requested alongside investigations such as calcium, phosphorus, vitamin D, parathyroid hormone (PTH), and other bone turnover markers to provide a more complete assessment of bone health. The findings are interpreted in the context of the individual’s symptoms, medical history, imaging studies, and other laboratory results.

Other names

●     Ostase test
●     BAP, serum
●     Bone-specific alkaline phosphatase
●     BsALP test
●     Osteoblast-specific ALP test