Bone Mineral Density Test
What is it?
As we age, our bones become weaker, less dense and more fragile. A condition called osteoporosis may eventually develop. People with osteoporosis are at increased risk of suffering from bone fractures. Their bones have low mass and poor quality and they can easily break, sometimes with only mild impact. Osteoporosis does not cause any symptoms though and many people only find out they have it after they have already had a fracture.
Bone mineral density (BMD) test is a test used to estimate how strong your bones are. It can find out if your bone mass is lower than normal or if you already have osteoporosis. It can calculate your risk of developing a bone fracture and it can also be used to measure how your bone is responding to the treatment.
How is this test done?
There are a variety of tests that can determine your bone mineral density:
Ultrasound testing — Ultrasound can measure the bone density of the heel which correlated to the likelihood of fracture. It does not diagnose osteoporosis though.
Quantitative computerized tomography (CT) — It can measure the bone density in the spine. Because of the amount of radiation involved in this test, it is not routinely used.
Dual-energy x-ray absorptiometry (DXA) — This the most commonly used test to assess the BMD. It uses a special kind of x-rays that expose you to little radiation. It measures the BMD in multiple bones in your body, usually your hip, spine and wrist. It is the test used to diagnose osteoporosis and it can also be used to check how the treatment is working in people with this condition.
Who should be tested?
Because osteoporosis appears more often in postmenopausal women, it is usually recommended that women get tested after age 65 or after menopause if they have risk factors for fractures such as:
- Cigarette smoking
- Low body weight (less than 127 lbs or 58 kg)
- Long-term use of steroid medications
- Rheumatoid arthritis
- History of a non-traumatic or low trauma bone fracture in self or parents (eg, breaking a bone after falling from standing height or less)
- Excessive alcohol consumption (three or more servings a day)
- Diseases that are associated with osteoporosis, such as diabetes, hyperthyroidism, hyperparathyroidism, early menopause (earlier than 40 years of age), chronic malnutrition or malabsorption, or chronic liver disease
How is DXA scan done?
During this test, a scanner will be passed over your body while you are lying on a table. There is no preparation needed for the exam but the x-ray detector will detect any metal on your clothing, so you may be asked to wear a gown for the test. It usually takes less than 10 minutes and you should not feel any pain. The test will result in scores that speak to the strength of your bones.
The BMD measured from your bones will then be compared to the average BMD of young, healthy women and this will result in a “T score”. It will also be compared to BMD of women of your own age, sex and race resulting in a “Z score”. The T score is the one used to diagnose osteoporosis and to calculate your risk of bone fracture:
- T-score of +1 to -1.0 or greater is normal
- T-score of -1.0 to 2.4 is called osteopenia or low bone mass
- T-score of -2.5 or less diagnoses osteoporosis
If your result is normal, you can help keep your bones strong by getting enough calcium and vitamin D daily and by doing weight-bearing exercises.
If you are found to have low bone mass, your doctors will discuss with you options to try to prevent further bone loss. Sometimes that will include medications.
When osteoporosis is diagnosed, you and your doctor will decide what will be the best treatment option for you. You will also receive information on how to avoid fractures.
Who will see patients who are candidates for Bone Mineral Density Tests?
How does a patient schedule a Bone Mineral Density Test?
When a bone mineral density test is recommended, our generalists will place an order in EPIC. A referral is required to schedule this test. Once an order has been placed in EPIC, either the Department of Nuclear Medicine will call the patient to schedule this test or the patient can call 414-805-3771.