This assay is intended for use in monitoring therapy following the diagnosis of osteoporosis in post-menopausal women and in patients diagnosed with Paget’s disease of the bone.
More than 90 % of organic bone matrix consists of type 1 collagen, which is preferentially synthesized in bone. Type 1 collagen is derived from type 1 procollagen which is synthesized by fibroblasts and osteoblasts. Type 1 procollagen contains both N‐(amino) and C‐(carboxy) terminal extensions. These extensions (propeptides) are removed by specific proteases during the conversion of procollagen to collagen and its subsequent incorporation into the bone matrix. The extension measured by this assay is the amino terminal, hence P1NP‐type 1 procollagen amino‐terminal‐propeptide. This marker, P1NP, is therefore a specific indicator of type collagen deposition and thus may be defined as a true bone formation marker. P1NP is released during type 1 collagen formation into the intracellular space and eventually into the blood stream. P1NP appears to be released as a trimeric structure (derived from the trimeric collagen structure) but is rapidly broken down to a monomeric form by thermal degradation effects.