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Monitor antiresorptive therapy with estrogen and calcium supplementation as well as drug therapy
Enzyme immunoassay (EIA)
• Male: 5.4−24.2 nM BCE/L
• Female: 6.2−19.0 nM BCE/L
Approximately 90% of the organic matrix of mammalian bone consists of type I collagen that is cross-linked at the N-terminal and C-terminal ends.1 This highly cross-linked structure provides for the basic fabric and tensile strength of bone tissue. The collagen infrastructure of bone undergoes a continuous process of remodeling that involves osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Bone resorption by osteoclasts results in the production of cross-linked N-telopeptides of type I collagen (NTx). NTx is specific to bone and is found in serum and urine as a stable end product of bone degradation. Serum levels of NTx have been shown to correlate well with urine NTx normalized to creatinine.2,3 The NTx test measures the concentration of cross-linked N-telopeptides of type I collagen.1 Levels of NTx correlate with the rate of bone resorption.2,3 Bone resorption rates exceeding bone formation result in a net loss of bone and ultimately osteopenia or osteoporosis.4 Osteoporotic fractures are a major source of morbidity and mortality in older women.5 The level of serum NTx correlates with bone mineral density in elderly women.6 The serum NTx test can be used to monitor the efficacy of antiresorptive therapy with estrogen and calcium supplementation7 as well as drugs such as alendronate.8
0.3 mL (Note: This volume does not allow for repeat testing.)
Red-top tube or gel-barrier tube
Serum must be transferred to a plastic transport tube. Serum must be separated from red cells or gel-barrier immediately after clot formation and centrifugation.
Causes for Rejection
Nonserum specimen; serum specimen received on cells or on gel-barrier
For monitoring therapy, baseline specimens should be collected just prior to or on the day of therapy initiation. Subsequent specimens for comparison should be collected at approximately the same time of day as the baseline specimen.
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|140830||N-Telopeptide, Serum||21215-9||140831||N-Telopeptide, Serum||nmol BCE/L||21215-9|