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Test Code P1NP Intact Procollagen I N-Terminal, Serum


Specimen Required


Patient Preparation: For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL Serum

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Secondary ID

624113

Useful For

Aiding in monitoring antiresorptive and anabolic therapy in patients with osteoporosis

 

This test should not be used as a screening test for osteoporosis in the general population.

Method Name

Chemiluminescence

Reporting Name

Intact Procollagen I N-Terminal, S

Specimen Type

Serum

Specimen Minimum Volume

Serum: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 14 days
  Frozen  90 days
  Ambient  7 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Clinical Information

Procollagen type I propeptides are derived from collagen type I, the most common collagen in mineralized bone. In bone, collagen is synthesized by osteoblasts in the form of procollagen, a precursor that contains a short signal sequence and terminal extension peptides: amino-terminal propeptide (PINP) and carboxy-terminal propeptide. These propeptide extensions are removed by specific proteinases before the collagen molecules form. Both propeptides circulate in blood, and their concentrations reflect the rate of collagen type I synthesis. Although collagen type I propeptides may also originate from other tissues, including skin, vessels, fibrocartilage, and tendons, most nonskeletal tissues exhibit a slower turnover than bone and contribute very little to the circulating pool of PINP. PINP is considered the most sensitive marker of bone formation and is particularly useful for monitoring bone formation and antiresorptive therapies. Testing is recommended at baseline before osteoporosis therapy begins and again 3 to 6 months later.

Reference Values

Adult male: 26-108 ng/mL

Adult female premenopausal: 22-103 ng/mL

Adult female postmenopausal: 18-119 ng/mL

 

Reference values have not been established for patients who are younger than 18 years.

Interpretation

This assay is specific for the intact trimeric form of procollagen type I N-terminal propeptide (PINP). When monitoring response to osteoporosis treatment, the reference change value (RCV) has been estimated to be -19.9% for decreases and +24.8% for increases from baseline PINP levels (ie, prior to the start of therapy), 3 to 6 months after initiation of therapy indicates an adequate therapeutic response.

 

The direction of the change in PINP levels (decrease or increase) will depend on the type of osteoporosis treatment. In patients taking bisphosphonates, PINP levels have been shown to decrease up to 70% from baseline after 6 months of therapy. Treatment with hormone replacement therapy also shows a decrease in PINP levels but to a lesser degree than bisphosphonate therapy.

 

In patients treated with teriparatide (recombinant human parathyroid hormone 1-34), PINP levels increase from baseline, reflecting the stimulatory effect of teriparatide on osteoblasts and bone formation. PINP levels have been shown to significantly increase as early as 1 month after teriparatide treatment, peaking at 6 months following treatment. Increases greater than 10 mcg/L have been reported in 77% to 79% of teriparatide-treated patients after 3 months of therapy and are considered a successful response.

CPT Code Information

83520

LOINC Code Information

Test ID Test Order Name Order LOINC Value
P1NP Intact Procollagen I N-Terminal, S 77370-5

 

Result ID Test Result Name Result LOINC Value
P1NP Intact Procollagen I N-Terminal, S 77370-5