Osteoporosis is often diagnosed after the weakening of the bones has led to a fracture.
If you at high risk of osteoporosis your GP may refer you for a bone density scan, known as a DEXA scan.
X-rays are not a reliable method of measuring bone density, but are a useful way of identifying fractures.
DEXA scan
A DEXA (dual energy X-ray absorptiometry) scan can help diagnose osteoporosis. It is a painless procedure that takes around 15 minutes to perform.
It measures your bone mineral density (BMD) and compares it to the bone density of a healthy young adult and someone who is of the same age and sex as you.
The difference between your BMD measurement and that of a healthy young adult is calculated as a standard deviation (SD) and called a T score. Standard deviation is a measure of variability based on an average or expected value. A T score of:
- above -1 is normal
- between -1 and -2.5 is classed as osteopenia (where bone density is lower than average but not low enough to be classed as osteoporosis)
- below -2.5 is classed as osteoporosis
A bone density scan can help diagnose osteoporosis, but your BMD result is not the only factor that determines your risk of fracturing a bone.
Your doctor will also consider your age, sex and any previous injuries before deciding whether you need treatment for osteoporosis.
If you do need treatment, your doctor will suggest the safest and most effective treatment plan for you.