Results of this assay should be used in conjunction with other pertinent clinical information for making diagnostic and therapeutic decisions. Therefore, the UniQ PINP assay is not recommended for use as a screening procedure to detect the presence of osteoporosis in the general population.
When evaluating subsequent samples, collect the samples at the same time of the day, as there is a diurnal variation of PINP with the values being higher at night.
Type I collagen is also synthesised by fibroblasts and therefore can be found in loose connective tissues together with other collagen types. However, since bone is the major collagenous organ and also metabolically active throughout life, the majority of the circulating PINP is of osteoblast origin.(1)
PINP is metabolised in the liver.(2) Severe liver disease may affect clearance from the circulation and give rise to elevated serum PINP levels.(3)
As with most assays utilising secondary antibodies, samples containing antibodies (such as heterophilic antibodies) that react with rabbit/goat IgG may cause erroneous results.
1. Risteli J and Risteli L. Products of bone collagen metabolism. In: Seibel MJ, Robins SP, Bilezikian JP(eds). Dynamics of bone and cartilage metabolism. Academic Press, San Diego, 1999. p 275-287.
2. Melkko J et al. Clearance of the aminoterminal propeptides of types I and III procollagen is a physiologicalfunction of the scavenger receptor in liver endothelial cells. J Exp Med 1994;79:405-412.
3 Naylor KE and Eastell R. Measurement of biochemical markers of bone formation. In: Seibel MJ, RobinsSP, Bilezikian JP (eds). Dynamics of bone and cartilage metabolism. Academic Press, San Diego, 1999. p401-410.