This Web site is not providing medical advice. The sole purpose of this section is to provide a general overview of bone densitometry for patients and individuals who wish to improve their understanding of this technology: what it is, how it’s done and what the results mean. You should discuss your individual needs with your doctor or other healthcare provider. All medical decisions should be made by your doctor in consultation with you and any other relevant parties.

Crisis in Osteoporosis Care

Prevention is the cornerstone of our evolving health care system today. Unfortunately, a critical test in the identification of Osteoporosis, DXA, continues to be in jeopardy because of Medicare policy changes.

Join us in our fight to preserve quality osteoporosis testing. Visit our ISCD Advocacy Web site for more information and to sign up to be part of the ISCD advocacy campaign. Click here to go to the ISCD Advocacy Web site now.

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What is the ISCD?

The International Society for Clinical Densitometry® (ISCD) was established in 1993 as a nonprofit professional medical society dedicated to advancing excellence in the assessment of skeletal health by:

  • Promoting education and a broader understanding of the clinical applications of bone mass measurement and other skeletal health assessment technologies
  • Assuring proficiency and quality in the assessment of skeletal health through certification and accreditation
  • Supporting clinical and scientific advances in the diagnosis and treatment of osteoporosis
  • Promote appropriate patient access to bone mass measurement and other skeletal health assessment technologies

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ISCD members include clinicians, technologists and other healthcare professionals from over 50 countries. Clinicians of all medical specialties, densitometry technologists and others involved with bone densitometry may be members. The ISCD publishes the Journal of Clinical Densitometry® and a quarterly e-newsletter called SCAN®. It is governed by an elected President and Board of Directors and managed by full-time staff. ISCD updates its Official Positions following Position Development Conferences.

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What is Osteoporosis?

Note: Links to other sites that cover osteoporosis in more detail are available on the Patient Resources page.

Osteoporosis is a disease of the skeleton whereby the bones become brittle making them prone to break more easily, often with little or no trauma. This means that simple things like coughing, getting out of a chair, or falling from a standing height can result in a broken bone (what doctors call a fracture). Although osteoporosis can occur in both men and women of all ages and ethnicities, it is primarily a disease of older individuals, with women being more likely to develop it than men. Primary osteoporosis is mainly a result of an individual’s genetic background, but there are many other diseases, conditions, genetic disorders, medications, and lifestyle factors that can affect the skeleton and result in secondary osteoporosis.

Osteoporosis is a very big problem today, in part because people are living longer. Current estimates suggest that 200 million people or more worldwide have osteoporosis. In the United States there are greater than 2 million osteoporotic fractures annually, making it one of the most common diseases of the elderly. Unfortunately, despite recent advancements, studies show many people are not evaluated or treated for their disease, in part because they do not know they have it or understand the consequences.

There are no obvious symptoms of osteoporosis until someone has a fracture. A fracture is a medical term for a broken bone. Although any site in the skeleton can fracture, studies show this is more likely to occur at certain places such as the spine (vertebra), hip and forearm. If a fracture does occur, it can cause pain and disability. However not all fractures cause pain and studies show over half the people who suffer spinal (vertebral) fractures experience no pain at the time of their fracture. Other symptoms these people might notice are loss of height (shrinking 1 inch or more), stooping of their posture and shortness of breath. People who suffer osteoporosis related fractures are more likely to have another fracture than people who do not, and they also have a higher risk of dying due to complications from fracture.

In the past, osteoporosis could not be easily diagnosed until a fracture occurred. Today most people who are at risk can be identified before a fracture occurs. This allows them to start appropriate treatment programs, the goal of which is to prevent fractures occurring in the first place. Even if a fracture has already occurred, lifestyle changes and medications today can significantly reduce the risk of further fractures.

Discuss with your doctor or healthcare provider whether you are at risk for developing osteoporosis and if you meet the criteria for a screening for osteoporosis.

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How do I know if I have osteoporosis?

There are two ways of making a diagnosis of osteoporosis:

  1. One way is when a “fragility fracture” has occurred. This is a broken bone that has happened with no trauma or minimal trauma, such as if you were to cough or fall to the floor from a standing position. The diagnosis in this case would be after you have experienced a fracture. Clearly the better choice is to find out if you have osteoporosis by measuring your bone density BEFORE a fracture occurs so that treatment can be started to lower your risk of fracture. But even if you have already had an osteoporotic fracture, treatment can lower your risk of having another. Sometimes other investigations such as blood tests are needed to diagnose other causes of osteoporosis or low bone mass.
  2. Have a bone density test. A bone density test measures your bone density in grams/centimeter squared. The machine that does this then calculates a score based on this reading and other information. In general the lower the bone density, the weaker the bones, and the more likely they are to break. The resulting score is a mathematical method for comparing your bone density to that of a healthy younger person.

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What is bone densitometry?

Bone densitometry is a non- invasive method of measuring bone density. Bone density is a measurement used to estimate bone strength and the likelihood of bones to break (fracture) with little to no trauma. However, it is only part of an overall assessment of fracture risk that your doctor or healthcare provider can perform.

A standard X-ray is not an accurate way to assess bone density.

There are different techniques for measuring bone density. The currently accepted “gold standard” method is called “Dual Energy X-ray Absorptiometry” — abbreviated DXA. (The ISCD Official Position abbreviation is DXA)

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Are there different kinds of bone density tests?

Yes. Bone density testing devices are divided into two types – diagnostic and screening.

Diagnostic Tests
Screening Tests
Central/large table top DXA Peripheral DXA (pDXA)
Quantitative Computerized Tomography (QCT) Quantitative Ultrasound (QUS)
  Peripheral QCT Scanning (pQCT)

Diagnostic Tests

Central/large table top DXA is a non- invasive and painless examination consisting of very low dose X-ray. Very low doses of X-ray (about 1 day of background radiation from natural sources) are used to rapidly scan your bones. A computer converts this information to numbers indicating your bone density. This is a high technology test which involves no injections, medications, or contrast materials. These tests measures bone mineral density (BMD) at the spine, hips and sometimes the radius (forearm) and rarely the whole body. They are generally considered the “gold standard” method of measuring BMD for diagnosing osteoporosis and monitoring the effects of osteoporosis therapy.

Diagnostic can also be performed using quantitative computerized tomography (QCT) scanning. This is a specialized type of computerized tomography (CT scan or CAT scan) that requires use of much larger doses of X-ray radiation. However, this method is currently only used to measure the spine and is not directly comparable to other scanning techniques.

Screening Tests

Screening tests with peripheral devices measure bone mineral density (BMD) at other skeletal sites, such as the heel, or finger. This can be accomplished by several technologies today including peripheral DXA (pDXA), quantitative ultrasound (QUS), and peripheral QCT scanning (pQCT). They may be used to estimate fracture risk or SCREEN individuals for low bone mass, particularly when diagnostic testing is not available.

However, currently the ISCD recommends that they not be used to diagnose osteoporosis or monitor the effects of therapy because they have less reliability and responsiveness. If an individual has low bone mass using peripheral technology, the ISCD currently recommends they have a diagnostic DXA measurement. Link to ISCD Official Positions.

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What should I expect at that time of BMD testing?

This depends on the type of bone density test (diagnostic or screening) you are having done. However, all are non-invasive and do not involve injections or contrast materials. Diagnostic DXA Scanning: You will be asked to fill out a short patient information questionnaire regarding your health history. An accurate height (without shoes) and weight will be taken. The lumbar spine/hips along with sometimes the radius (forearm) are considered routine for a central DXA scan. Each scan site takes less than five minutes to complete.

Some items to consider as you prepare for your test include:

  1. Are you pregnant? If so, tell the technologist so that the scan can be postponed.
  2. Eat a normal diet on the day of the test.
  3. Take your medications as you normally would.
  4. DO NOT take calcium supplements for 24 hours before the test.
  5. On the day of the test, leave valuables at home.
  6. Do not wear jewelry or body piercings to the examination.
  7. The test should be performed prior to oral, rectal or IV contrast studies, or at least 7 days after any of these studies.

Additional information for diagnostic DXA testing. You will need to lie on your back, on a padded table for several minutes while the technologist scans your lower back and hip(s). You will be asked to assist the technologist to rotate each hip that is to be scanned internally. For the lower back (lumbar area) you may be asked to bend and elevate your knees which will rest on a block or you may remain in a flat position. You can breathe normally but should remain as still as possible during the procedure. You can resume your usual activities immediately. Your forearm scan may be performed while sitting in a chair next to the machine.

For screening/peripheral testing of the heel, you may have to remove your shoe and sock and a clear gel may be applied to the area being examined.

VFA (vertebral fracture assessment) is a newer technology used to assess the spine for fractures. VFA is performed for the sole purpose of detecting vertebral fractures in the lumbar and thoracic regions of the spine. It cannot be used in diagnosing or monitoring Bone Mineral Density. The advantages of using VFA instead of conventional x-ray include cost and less radiation to you as a patient.

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Where should I go for a bone density test?

This depends on where you live. For some individuals there may be many options, while for others there may be few or none. Today bone density testing is much more widely available in many countries and performed in many settings including hospitals, other healthcare imaging facilities, doctors’ offices, screening health fairs, pharmacies and sometimes as part of a mobile health unit. Although travel, cost and convenience are important things to consider when making this decision, there are also technical issues to take into account so you get the best available value for your money.

It is important that the DXA facility clinicians and technologists are adequately trained in bone densitometry. One indicator that the technologist and clinician have received appropriate training in bone densitometry is to ask if they are ISCD Certified. You can also search the online ISCD Certification Registry to find a certified technologist (CDT or CBDT) or certified clinician (CCD) in your area. The ISCD Certification Registry lists participating certified individuals — Certified Clinical Densitometrist® (CCD), Certified Densitometry Technologist® (CDT) and in the United States, Certified Bone Densitometry Technologist™ (CBDT). Individuals may choose not to be displayed in this listing. Evaluation of the credentials, qualifications and competence of a physician or technologist is the responsibility of the person referencing the registry.

It is also important that you always attempt to return to the same facility that performed your baseline test to allow for precise comparison of follow-up results.

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Who should have a bone density test?

Consult with your physician if you think you might benefit from knowing your bone density. The test is most often administered to those at highest risk of developing osteoporosis, or to monitor the effectiveness of treatment for osteoporosis. However, because osteoporosis is such a common disorder, many other persons may warrant this evaluation.

Although the testing procedure is generally very safe, because of cost concerns and inappropriate testing that may result in unnecessary treatment and worry, the test is most often administered for those with high risk of developing osteoporosis, or to monitor the effectiveness of treatment for osteoporosis.

Guidelines for who is recommended to undergo BMD testing differ between countries and societies. These guidelines continue to evolve as our technology and knowledge advances.

The ISCD currently recommends that a bone density test be done for:

  • All women aged 65 and older.
  • All men aged 70 and older.
  • Anyone with a fragility fracture.
  • Anyone with a disease, condition or medication associated with osteoporosis.
  • Anyone who is considering therapy for osteoporosis, if bone density testing would facilitate the decision.
  • Women who have been on hormone replacement therapy for prolonged periods.
  • Anyone being treated for osteoporosis, to monitor the effects of therapy.

In areas where DXA is less available, FRAX or other fracture risk assessment tools may be used to identify those patients who should receive a DXA measurement.

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When should a bone density test be repeated?

This depends on why it is being recommended — whether as a follow-up to the results of previous testing, to monitor therapy, as a screening tool, or for some other reason. Guidelines for how often the test should be repeated, or will be covered by your insurance or health system, differ. In some situations, such as starting high dose glucocorticoid therapy, like prednisone or prednisolone, a test may be done as often as every six months. After starting a medication for osteoporosis, it may take one or two years or longer before a significant change in bone density has occurred.

You should discuss your individual needs with your physician.

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Will this test be covered?

Like most medical tests, it is variable. At this time, most insurance companies and governments have a very specific list of diagnoses that will qualify you for coverage to have bone densitometry done. The list is different for each type of payor and sometimes a pre-authorization may be required before the test is scheduled. Your physician’s office, local healthcare authority or insurance company can give you more information on whether or not this test will be covered, and where you should go to have the test done in order to be covered. If you and your physician feel that the test should be performed, even if not covered by insurance, then arrangements may be possible for self-pay.

Out of pocket expenses for BMD differ between geographical areas and depend on a number of factors. You should ask your local bone density center what you can expect to have to pay to get the most accurate information.

In the United States, Medicare (the primary government payor) has the following guidelines for who should have a BMD. They currently will cover a bone density test for the following situations:

  • Estrogen deficient women at risk for Osteoporosis.
  • Those with spinal abnormalities or X-ray evidence of bone loss.
  • Anyone taking long-term corticosteroid treatment (such as prednisone).
  • Primary hyperparathyroidism with no symptoms.
  • Monitoring of therapy for osteoporosis.

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Author Information

John J. Carey, MB, BCh, MS, CCD
Sharon R. Wartenbee, RT(R)(BD), FASRT, CBDT

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Last modified: November 18, 2016