What are bone markers?
Bone marker tests bone by-products levels in your urine or bloodstream. These tests are essential for baseline measurements prior to treatment with some anti-osteoporosis medication. Besides baseline testing, you can also measure your increases or decreases in bone by-products found in blood or urine, which will tell you if you are losing or making new bone. In turn, this can tell you if your current treatment is working. These tests are not used to diagnose osteoporosis, but they can give important information about the state of your bone remodeling to you and your physician.
According to the Georgia Reproductive Specialists, "bone is an active living tissue made of a protein framework to which various minerals attach. Throughout life, bone is constantly dissolved in a process called bone resorption and reformed in a dynamic process called bone remodeling. This is a function of two types of cells, osteoclasts (bone resorption) and osteoblasts (bone formation). As bone is resorbed by osteoclasts, bone collagen degradation fragments are released into the bloodstream and excreted in the urine."
Bone markers come in resorption and formation tests.
Resorption markers tell you how much bone you are losing.
Formation markers tell you how much new bone is created.
- NTx (N-telopeptide)
- CTx (C-telopeptide)
- P1NP (total pro-collagen type 1 N-terminal pro-peptide) has been reported to be a marker for bone metastases of several types of carcinoma (Canterbury Health Laboratories. 2008). This is the preferred test to measure bone formation.
- OC (osteocalcin)
- BSAP/BAP (bone specific alkaline phosphatase).
The University of Washington's bone physiology course has a full listing of resorption and formation markers.
Some insurance companies don't cover the cost of these tests and some do. Medicare will cover some of these tests if your health care provider is considering a new treatment for you. When starting a new treatment it is important to have a baseline score so your doctor can compare future test results to this baseline score taken before you start a new treatment medication. With the testing done after a new treatment is started you and your doctor will be able to tell how you are doing with the treatment instead of having to wait for your next DXA scan which would provide your bone mineral density (BMD) score. Many of us can't afford to wait for the next DXA scan to determine if we are improving or not. Medicare only covers DXA scans every 2 years, unless there is a medical necessity to have this test performed sooner.
Patients with complex bone loss issues benefit the most from these tests since it provides information that the standard DXA scan does not. If you're taking an anabolic, such as Forteo, it's important to know these resorption and formation levels since Forteo increases the growth of new bone along with slowing down resorption (bone loss). It's best to check both resorption and formation markers since you'll want to know how much bone you are losing and how much you are creating. In addition to establishing how you are doing on your current medication, these tests also provide information to your physician about the best next type of bone loss treatment.
If you feel you may benefit from these types of biochemical markers of bone tests, ask your physician about it and how they might provide more information on your current treatment and future choices of anti-osteoporosis medications.
Osteoporosis and Bone Physiology. (3-22-2012) Biochemical Markers of Bone Cell Activity. Retrieved 12-24-2014 from http://courses.washington.edu/bonephys/opmark.html
Georgia Reproductive Specialist (2007) Bone Loss the Cost to your Health. Retrieved 12-24-2014 from http://www.ivf.com/ostem.html