The bone-specific isoform of alkaline phosphatase is known as bone alkaline phosphatase (BAP). BAP, a glycoprotein that is present on the surface of osteoblasts, is a biomarker for the activity of these bone-forming cells during biosynthesis. It is thought that BAP blood levels reflect the metabolic state of osteoblasts. Precise assessment of bone metabolism is crucial for assessing the severity of metabolic bone disease and responses to medication. Patients with Paget's disease, osteomalacia, primary hyperparathyroidism, renal osteodystrophy, osteoporosis, and metastases to the bone have been proven to benefit from having their serum BAP levels measured. In osteomalacia and Paget disease, BAP concentration is elevated.