Biological or Clinical Significance:
Collagen type I is present in soft connective tissues and bone, where it constitutes more than 90% of the organic matrix. During bone formation collagen type I is synthesized from pro-collagen type I, which is secreted from fibroblasts and osteoblasts. Pro-collagen type I contains N-and C-terminal extensions, which are removed by specific proteases during the conversion of procollagen to collagen. The extensions are referred to as the C- and N- terminal propeptides of procollagen type I (PICP and PINP). Thus, measurements of PINP can be of value in assessing bone formation.
Principle of Test Method:
The PINP assay is a sandwich immunoassay using electrochemiluminescent detection.