Osteoporosis is a common bone disorder known to affect people over 50 years old. As people age, their risk of osteoporosis rises along with the risk of bone fractures.
Bone mineral density tests like bone densitometry or bone scans are common methods recommended for the diagnosis of Osteoporosis.
However, there are a few other tests that can help to diagnose. blood tests for osteoporosis are one of them. Let’s have a look at the blood tests that can assess bone density and evaluate the risk of osteoporosis.
What is osteoporosis?
Bone is a living tissue in the body that constantly undergoes breakdown and rebuilding. Bone tissue undergoes wear and tear throughout our life as it is subjected to pressure, strain, and injuries while performing day-to-day activities.
Damaged and lost bone tissues are generally rebuilt at a faster rate in younger people.
As age advances, the balance between rebuilding and breakdown is disrupted due to factors like degeneration, hormonal changes, and dietary changes.
As a result, bones begin to lose some of the minerals and tissues that contribute to their healthy matrix, strength, and density.
When a significant loss occurs in bone density, making the bones markedly weak and porous, the condition is referred to as osteoporosis. 
In short, osteoporosis is a disorder caused by reduced bone mineral density resulting in weak, spongy, porous bones that are prone to fractures.
In addition to bone scans, there are blood tests for osteoporosis that can help in the early diagnosis of osteoporosis.
Blood tests for osteoporosis diagnosis
If you are over 50, your physician may recommend blood and urine tests to assess your bone health and your risk of developing osteoporosis.
If you are already undergoing treatment for osteoporosis, these tests can give clues to whether the condition is progressing or is under control.
The tests include measuring levels of specific proteins, enzymes, hormones, minerals and vitamins in your blood. Typical tests measure:
1. Calcium levels
This test determines blood calcium levels to detect any deficiency of this mineral. Low blood calcium levels indicate a higher risk of osteoporosis. 
2. Vitamin D levels
The measure of vitamin D in the blood helps to determine the risk of osteoporosis. Vitamin D is essential for the absorption of calcium in the body.
Even people who are consuming calcium-rich foods or using calcium supplements may develop osteoporosis if calcium is not being absorbed into the body due to a vitamin D deficiency. 
3. Bone ALP or BALP
Bone ALP or BALP (Bone-specific alkaline phosphatase) test provides an estimate of the rate at which bone formation is occurring in your body. While bone formation sounds like a good or healthy thing, excessive bone formation is not a healthy sign.
Patients with osteoporosis usually have very high BALP levels. In severe cases, the BALP levels may be up to 3 times higher than normal.  An increased BALP level could indicate a higher risk of osteoporosis or a rapid bone loss. 
Osteocalcin is another marker for bone formation. A change in osteocalcin levels in the blood indicates a risk of osteoporosis.
According to a research study published in the International Journal of Advances in Medicine:
“Osteocalcin has a high affinity for calcium. In osteoporotic women, deficiency of calcium may lead to the lowering of the formation of hydroxyapatite crystals. Thus, in the state of hypomineralization, free osteocalcin is available in circulation.
Serum osteocalcin can be considered as a specific marker for osteoblast function as its levels have been shown to correlate with bone formation rates.
Thus, serum osteocalcin can be used for the diagnosis and the monitoring of response to therapy and this may be a better predictor than BMD.” 
These findings suggest a deficiency of calcium can reduce the hydroxyapatite crystals that are formed when osteocalcin binds with calcium. As a result, a higher amount of osteocalcin remains freely available in the blood.
Increased levels of osteocalcin in the blood can indicate a deficiency of calcium and thus, helps in the diagnosis of osteoporosis.
uNTX or Urinary N-telopeptide of type I collagen is a marker for bone resorption. It shows the rate at which bone loss is occurring in your body.
According to a research study published in the Journal of Osteoporosis:
“High uNTX is an indicator of increased bone resorption. Studies have demonstrated that uNTX is a significant predictor of fracture risk in postmenopausal women in addition to other bone resorption markers.” 
This test is specifically recommended for postmenopausal women to assess their bone health. An increased level of uNTX could indicate increased bone resorption and a high risk of developing fractures.
This can allow women to take the necessary amounts of calcium and vitamin D supplements and to take precautions in their everyday activities to reduce their risk of fractures.
Some other bone resorption markers that help detect bone loss include:
- Pyridinium Crosslinks
- Urinary hydroxyproline
- Bone sialoprotein
- Tartrate-resistant acid phosphatase 5b
Other tests recommended for the diagnosis of osteoporosis and the underlying disorders responsible for it include:
- Thyroid tests like T4 and TSH to evaluate the risk of thyroid diseases
- Parathyroid hormone to check for hyperparathyroidism
- Follicle-stimulating hormone to assess hormonal balances in menopausal women
- Protein electrophoresis to detect abnormal proteins produced in patients with blood cancers such as multiple myeloma that may cause faster breakdown of bone tissues
Blood tests are highly sensitive and can help in the early diagnosis of osteoporosis. Blood tests provide an easy alternative for the diagnosis of osteoporosis, especially for people who find it inconvenient to undergo extensive bone densitometry tests and scans.
Blood tests for osteoporosis can be performed during routine visits to the doctor, along with the other blood tests you need, allowing for early diagnosis of osteoporosis.