BONE ALKALINE-PHOSPHATASE - METHODS OF QUANTITATION AND CLINICAL UTILITY

Bone and liver alkaline phosphatases are the predominant alkaline phos phatase (ALP) isoenzymes in serum and are the product of a single gene . Methodologies including heat inactivation, chemical inhibition, whea t germ lectin precipitation, and electrophoresis developed over the pa st decades to quantitate bone ALP in serum are thought to exploit the carbohydrate differences between bone and liver ALP, Recent advancemen ts in assay technology for serum bone ALP quantitation have included t he development of monoclonal antibodies with high specificity for bone ALP, These antibodies have been used to develop immunoassays in vario us formats that allow more widespread use in clinical chemistry labora tories, Clinical data demonstrate that bone ALP is a sensitive and rel iable indicator of bone metabolism. Although a direct product of the o steoblast, the cell that forms bone during bone remodeling, bone ALP r eflects overall bone turnover when the bone resorption and formation p rocesses remain coupled. In osteoporosis, measurement of serum bone AL P can be an effective tool in monitoring response to osteoporosis ther apies and may also be useful in assessing a woman's risk of subsequent bone loss and fracture.