By Dr. Susan E. Brown, PhD
Bone is living tissue where many minerals are embedded. And as bone breaks down, its by-products appear in the urine and blood. By measuring these bone by-products, the N-telopeptide or NTx test is one new way to evaluate the rate at which your bones are undergoing bone resorption.
This test because it provides a dynamic measurement of what is actually happening inside the bone at any given time. Bone density as measured by DEXA, on the other hand, provides a static, snapshot of your bones, and doesn’t distinguish if bone loss is ongoing or not. While a certain amount of bone breakdown is perfectly normal, a high rate of bone breakdown suggests that there may be long-term bone loss and, in time, a greater risk for fracture.
Tips for NTx testingAt the Center for Better Bones, Dr. Susan Brown uses the Osteomark NTx urine test to determine if her patients are undergoing excessive bone loss. Here are some of her tips:p
- Strive for the average premenopausal value:
36 bone collagen equivalent units/mmol creatinine. (The range is 5–65.) - To check your progress, do follow-up tests every 6–12 months.
- In general, a number somewhere between 30 to the mid-40’s bone collagen equivalent units/mmol creatinine should indicate a safe amount of bone turnover.
One of the most useful medical tests for bone health assesses the rate of bone breakdown, a process known as bone resorption.
The NTx test can measure N-telopeptide levels in the urine or blood. The box at right indicates a healthy range to strive for. NTx tests are also used by healthcare providers to determine whether antiresorptive medications, such as Fosamax, are stopping excessive bone breakdown.
