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Total Procollagen 1 N-Terminal Propeptide (Total P1NP)

Category Biochemistry >> Bone Metabolism
Test background

During the renewal of the skeleton, type 1 procollagen's amino- and carboxy-terminal regions are cleaved by specific proteases during its conversion to collagen and subsequent incorporation into bone matrix. The presence of these N-terminal extension propeptides, known as type 1 procollagen amino terminal peptides (P1NP), therefore reflects the deposition of collagen and can be defined as a marker of bone formation. P1NP is released into the blood stream during type 1 collagen formation. Elevated levels are found in patients with increased bone turnover. It is specifically used for monitoring of bone formation during anabolic therapy.

Clinical Indications

Assessing treatment response and compliance to osteoporosis therapy (such as bisphosphonates), but specifically the response to treatment by human PTH (Teriparatide).

Reference range

Pre-menopausal women: 15.1-58.6 ng/mL.
The least significant change for serum P1NP is ±25 %, with a reasonable response to hPTH therapy being an increase of at least ≥40 % (a very good response to therapy being an increase of between 100-200 %). Note that post-menopausal reference ranges are poorly defined. A post-menopausal reference range is available on request and is suitable for research studies only.

Sample & container required SST (gold top). Samples can be stored at 4 ºC for up to 1 week, or at -20 ºC for longer storage (other non-accredited but acceptable sample types include, EDTA (lavender top) or heparin (green top) tubes).
Sample volume 250 µL
Transport storage Stable at 2-8°C for 72 hours. Please freeze pending dispatch for analysis. Sample can be sent by first class post.
Turnaround time 4 weeks

If monitoring the response to treatment, the sample should be collected at the same time of day.
Falsely low results may be obtained for this test due to biotin interference. Samples should not be taken from patients receiving therapy with high biotin doses (>5 mg/day) until at least 8 hours (ideally 2 days) following the last biotin administration.

Grossly haemolysed samples are unsuitable for this assay.