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Bone Density Testing

Posted in Patient Services.

Bone Density

What is a bone density test?

A bone density test is called a DXA or DEXA scan. This is not the same as a bone scan. A bone density test uses a small amount of x-ray to measure the amount of mineral in the bones of your lower back, hip or sometimes the forearm.

How is a bone density test done?

You will lie on your back on a padded table wearing your street clothes or a patient gown. The machine does all the work, moving back and forth as it measures your bone density. The machine is very open and does not feel "closed in." You will not be given any injections or medications for this test.

How do I prepare for my test?

    • Prior to Exam
      • Avoid all calcium supplements, including Tums and multivitamins for two days.
      • Take all other medications as prescribed.
      • You may eat foods that contain calcium.
      • If you have had a barium or contrast x-ray in the past ten days, please call to reschedule your bone density test.
    • Day of Exam
      • Bring your insurance card, a photo ID and any written referral forms provided by your health care provider.
      • Remove body piercings located below the neck, if possible.
      • Do not wear clothing with underwire bras, metal buttons, zippers, metallic paint or threads.

May I take my medication before my test?

Yes. You should take your medications as usual.

May I eat before my test?

Yes. You should eat normally before your test. You can eat foods containing calcium before your test.

How much radiation exposure do I get?

The amount of x-ray exposure you get is about the same as one to two days of background radiation from daily life. This is less than the radiation you get from flying from the east coast to the west coast and about 1/10th of the exposure in a chest x-ray exam.

Can I have a bone density test if I am pregnant?

This test should be avoided during pregnancy.

How long does a bone density test take?

A bone density test takes about 15-20 minutes.

What does a bone density test tell my health care provider?

A bone density test tells your health care provider how much mineral you have in your bones. This measurement determines your T-score or Z-score.

    • T-score 
    • -1.0 or above is normal
    • Between -1.0 to -2.5 is considered osteopenia (low bone mass)
    • -2.5 or below is reported as osteoporosis
    • Z-scores are used for children, premenopausal women, and men below the age of 50. A Z-score of -2.0 or lower is considered below the normal range expected for your age group.

When should I get my first bone density test?

When to get your first bone density test should be determined by talking to your health care provider. Certain conditions and medications can influence when you have your first bone density test. If you are a woman age 65 or older, or if you are a man age 70 or older, you should have a bone density test.

Am I too young to get a bone density test?

Osteoporosis can affect anyone at any age. It is important that you discuss your risk factors with your health care provider to determine the age that is right for you to have a bone density test. Some of the risk factors include: being female, Asian or Caucasian ethnicity, using glucocorticoids (steroids), menopausal or postmenopausal, inactivity, small body build, smoking, alcohol use of more than 2 drinks per day, family history of osteoporosis and certain medical conditions. There needs to be a medically necessary reason for doing a bone density test. Talk to your health care provider about your risk factors and when you should have a bone density test. Often, insurance plans will provide guidelines about when and how often a bone density test can be done. Check with your insurance company about your coverage.

How often should a bone density test be done?

Usually a bone density test is done every two years. However, if you have certain medical conditions or take certain medications your health care provider may recommend more frequent testing. Follow up testing should be done at the same facility and on the same machine. You should check with your insurance company for how often this test will be covered.

What happens to my test results?

The bone density test results are read by our physician and then a detailed report is sent to the health care provider that ordered your test.

What is osteoporosis?

Osteoporosis is the most common skeletal disorder. In the United States, it is estimated that 8 million women and 2 million men have osteoporosis; and another 34 million people are at risk.

It is characterized by bone loss that can result in low impact fractures. Nearly 50% of women and 25% of men over the age of 50 years will have an osteoporosis related fracture in their lifetime. Osteoporotic fractures can decrease mobility and result in long term nursing home care.

Signs of osteoporosis include back pain, height loss and curving of the upper back (called a "dowager's hump"). If you have these signs or have had a low impact fracture, you should talk to your health care provider.

A low impact fracture is one that occurs when falling from sitting or standing height and typically involves the hip, spine or forearm.

How do I know if I have osteoporosis?

Osteoporosis does not have early warning signs. Many people are unaware that they have osteoporosis until a fracture has occurred. These fractures typically involve the spine, hip or forearm.

A measurement of your bone density (called a "DXA measurement") can determine if you are at risk for osteoporotic fractures.

 Your T-score will tell you if your bone density falls within the range of normal, osteopenia (low bone mass), or osteoporosis. 

  • T-score
    • -1.0 or above is normal
    • Between -1.0 to -2.5 is considered osteopenia (low bone mass)
    • -2.5 or below is reported as osteoporosis

You also have osteoporosis if you have had a fragility fracture. A fragility fracture is a low impact fracture that occurs when falling from sitting or standing height and typically involves the hip, spine or forearm. 

What is the difference between osteopenia and osteoporosis?

Osteopenia or low bone mass is diagnosed from your T-score. A T-score between -1.0 to -2.5 is considered to be osteopenia. Osteoporosis is defined as a T-score that is -2.5 or lower. Osteoporosis is a more severe disease process often needing medical treatment.

Can osteoporosis be prevented?

Most people can prevent osteoporosis by following the guidelines below:

    • Get the recommended amounts of calcium (1000-1200mg per day) and vitamin D (800-1000 IU per day)
    • Do regular weight bearing and strengthening exercise, such as walking, jogging, dancing, stair climbing and using hand held weights
    • Stop smoking and avoid excessive alcohol
    • Talk to your health care provider about your bone health
    • Have a DXA bone density test
    • Take bone building medication as recommended by your health care provider

Who is at risk for osteoporosis?

    • Women during and after menopause
    • People who exercise excessively resulting in loss of periods or significant weight loss
    • Caucasian and Asian ethnicity
    • Small boned and thin people
    • Elderly people
    • People with a family history of osteoporosis
    • Men with low testosterone levels
    • Smokers
    • Alcohol consumers
    • Inactive people
    • People with a diet low in calcium and vitamin D
    • People using certain medications (steroids, thyroid medication, chemotherapy)
    • People with some medical conditions like hyperparathyroidism and bowel disease

Who should have a bone density test?

    • Anyone who has had a low impact bone fracture. A low impact fracture is one that occurs when falling from sitting or standing height and typically involves a fracture of the hip, spine or forearm.
    • Women age 65 or older
    • Men age 70 or older
    • Menopausal women with risk factors
    • Postmenopausal women under age 65 with risk factors
    • Men age 50-69 with risk factors
    • Anyone with a broken bone after age 50

What exercises are good for healthy bones?

Bone healthy exercises are activities that are weight bearing. Examples of bone healthy exercises are: walking, jogging, dancing, stair climbing, jumping jacks and using hand held weights. You should talk to your health care provider about exercises that are appropriate for you.

Should I take calcium supplements?

If your diet is low in calcium, you may need to take a calcium supplement.

Adults need 1,000-1,200 mg of calcium per day. Dietary sources of calcium are ideal, but calcium supplements can be taken to reach the target amount.

Calcium supplements come in various forms, including chewable, liquid and pill.

Only 500 mg of calcium can be absorbed by the body at one time. Take calcium at different times during the day if you need to take more than 500 mg per day.

Calcium carbonate needs stomach acid to dissolve and is absorbed best when taken with food.

Calcium citrate is best absorbed when taken on an empty stomach with 8 ounces of water. This may be a better choice if you are taking an acid reducer/inhibitor since calcium citrate does not need stomach acid to dissolve.

Calcium supplements should be taken with vitamin D.

Read food labels to see the level of calcium in your food.

Adding fiber and increasing your fluid intake can help reduce constipation when taking calcium supplements.

Discuss your nutritional needs with your health care provider.

Calcium Rich Foods

  • Milk (1 cup) 250 mg
  • Cheddar cheese (1 oz.) 204 mg
  • Swiss cheese (1 oz.) 272 mg
  • Low fat yogurt (8oz.) 415 mg
  • Broccoli (3/4 cup) 175 mg
  • Spinach (1 cup) 291 mg
  • Salmon (3 oz.) 208 mg
  • Sardines (3 oz. with bones) 267 mg

Which calcium supplement is best?

The most common forms of calcium supplements are calcium carbonate and calcium citrate. Calcium carbonate is usually the least expensive and comes in many forms. Calcium carbonate needs to be taken with food in order to dissolve and be absorbed. Calcium citrate can be taken at any time, but is absorbed best taken with water on an empty stomach.

The body can only absorb 500 mg of calcium at a time, so you may need to take your calcium at different times of the day if you need more than 500 mg each day. It is important to take a calcium supplement with vitamin D. Ask your health care provider how much calcium and vitamin D you should be taking.

Should I take vitamin D?

Vitamin D is necessary to help the body absorb calcium and maintain healthy bones.

Your health care provider can determine your vitamin D levels by a blood test. If you do not get the recommended amount of vitamin D from exposure to sunlight or in your diet you may need a supplement.

Adults need 800 to 1,000 IU of Vitamin D per day.

Direct sunlight exposure to the skin for 10-15 minutes a day can provide a good source of Vitamin D.

People with Crohn's disease, celiac disease or kidney disease may be at risk for low Vitamin D levels.

Vitamin D2 or D3 supplements may be recommended by your health care provider.

Vitamin D Rich Foods

  • Fish (salmon) 465 IU
  • Fish (trout) 645 IU
  • Tuna (canned in oil) 229 IU
  • Tuna (canned in water) 154 IU
  • Milk (whole with added Vitamin D) 124 IU
  • Beef liver 42 IU
  • Egg 40 IU
  • Fish (cod) 40 IU

I had a bone density test done on my heel at a health fair. Do I need another bone density test?

Although portable bone density machines are used to do quick screenings at job sites or health fairs, this is not as accurate as doing a central bone density scan (DXA). A central bone density scan measures the bone density at the spine and hip. These bones are the more commonly broken bones. Central bone density (DXA) scans are considered to be the "Gold Standard" for measuring bone density.