Bone-Specific Alkaline Phosphatase (BSAP)

Bone-Specific Alkaline Phosphatase (BSAP, or BAP) is a crucial isoenzyme of alkaline phosphatase that is predominantly produced by osteoblasts, the cells responsible for bone formation. It plays an essential role in the process of bone mineralization by hydrolyzing phosphate esters, which increases local phosphate concentration and facilitates the deposition of calcium and phosphate to form hydroxyapatite crystals, the mineral component of bone. Due to its specific cellular origin, BSAP in the bloodstream serves as a direct and highly sensitive biochemical marker of osteoblast activity and the bone formation phase of overall bone turnover. The clinical significance of measuring serum BSAP levels is substantial. It is widely used in the diagnosis and therapeutic monitoring of metabolic bone diseases.