Women 65 and older, and younger postmenopausal women with elevated fracture risk, should get a baseline DXA scan under current USPSTF guidance. Hip and spine DXA remains the diagnostic standard, but how often you repeat it depends on your results and risk factors, not a fixed calendar. Medicare typically covers testing once every 24 months, with earlier coverage when it's medically necessary.
TL;DR:
- People starting or changing osteoporosis medication are often rescanned after about one year, while stable, low risk results may allow three to five years or longer.
- A T score of minus 1.0 or above is normal, while scores of minus 2.5 or lower indicate osteoporosis; diagnosis uses the lowest measured site.
- Skip calcium supplements for 24 hours before scanning, and tell staff about recent contrast imaging or barium studies because they can distort results.
- Repeat scans at the same facility, ideally on the same machine, because equipment differences can complicate comparisons over time.
- Before booking, confirm the clinic offers hip and spine DXA; heel ultrasound alone cannot establish a diagnosis, and equipment weight limits vary.
Table of Contents
- What a bone density (DXA) test measures
- Who should get a bone density test and when
- How the test works and how to prepare
- Reading your results: T-scores, Z-scores, and FRAX
- How often to repeat testing and what Medicare covers
- Limitations and situations that complicate results
- A practical note on getting tested
- Finding and booking a DXA scan near you
- FAQ
- Sources
What a bone density (DXA) test measures
Dual-energy X-ray absorptiometry, usually written as DXA or DEXA, sends two low-dose X-ray beams through bone to calculate mineral density. Central DXA machines, the kind found in hospitals and imaging centers, measure the lumbar spine, total hip, and femoral neck because fractures at these sites carry the greatest health consequences. A one-third radius reading is added when hip or spine results can't be interpreted or when a patient's weight exceeds table limits. Some facilities also perform a vertebral fracture assessment (VFA) during the same visit to check for spine fractures that don't cause obvious symptoms. The scan itself takes just a few minutes of imaging time, and radiation exposure is a small fraction of a standard chest X-ray.
Who should get a bone density test and when
The USPSTF recommends screening for all women aged 65 and older, along with younger postmenopausal women whose fracture risk matches or exceeds that of a 65-year-old woman with no added risk factors. Evidence is currently insufficient for the USPSTF to issue a routine screening recommendation for men, though many clinicians order DXA for older men with risk factors on a case-by-case basis. ACR appropriateness guidance and related practice standards expand the picture further, flagging additional groups who benefit from testing regardless of age.
Bring this checklist to your next appointment if any apply to you:
- You're a postmenopausal woman under 65 with a fracture risk factor such as low body weight or a parent's hip fracture.
- You've had a fragility fracture (a break from a fall at standing height or less) after age 50.
- You've taken glucocorticoid medications like prednisone for three months or longer.
- You have a condition linked to bone loss, such as rheumatoid arthritis, celiac disease, or hyperthyroidism.
- You're a man with risk factors including long-term steroid use, low testosterone, or a previous fragility fracture.
How the test works and how to prepare
A DXA appointment is brief and requires little special preparation, but a few details affect accuracy. Review the steps below before your visit:
- Eat and drink normally; fasting isn't required for this exam.
- Skip calcium supplements for 24 hours before your appointment, since they can interfere with imaging.
- Wear clothing without metal zippers, buttons, or underwire, or expect to change into a gown.
- Tell the technologist if you've had a recent CT scan with contrast or a barium study, since residual contrast can distort results.
- Let staff know if you're pregnant or think you might be, since DXA is generally avoided during pregnancy.
- Bring copies of prior DXA reports if you have them, especially if you're testing at a new facility.
Lie still on a padded table for 10 to 30 minutes while the scanner arm passes over your hip and lower spine. When possible, schedule follow-up scans at the same facility, ideally on the same machine, since different equipment can introduce small discrepancies that complicate tracking change over time.
Reading your results: T-scores, Z-scores, and FRAX
Your report translates bone density into a T-score, which compares your bone mass to that of a healthy young adult. The World Health Organization thresholds, used throughout DXA reporting, classify a T-score of -1.0 or above as normal, between -1.0 and -2.5 as osteopenia (low bone mass), and -2.5 or below as osteoporosis.
A few interpretation details matter:
- Diagnosis is based on the lowest T-score among the measured sites, not an average.
- Z-scores, which compare your density to people your own age and sex, are used instead of T-scores for premenopausal women and men under 50.
- Clinicians often plug your BMD and risk factors into FRAX, a calculator that estimates your 10-year fracture probability and helps decide whether medication is warranted.
- A VFA or spine X-ray may be added when height loss, back pain, or steroid use raises suspicion of a vertebral fracture that BMD numbers alone wouldn't catch.
- For a deeper walkthrough of what each score means for your next steps, see how to read your DEXA results.
A partner resource on what your DEXA results really mean offers another patient-friendly breakdown of T-scores and FRAX if you want a second explanation in plain language.
How often to repeat testing and what Medicare covers
Testing frequency isn't one-size-fits-all. Updated practice guidelines call for individualized intervals based on your baseline score and clinical picture, typically ranging from 1 to 5 years.
- People starting or changing osteoporosis medication are often rescanned in about a year to check whether treatment is working.
- Those with stable, low-risk results may wait 3 to 5 years or longer between scans.
- The Endocrine Society notes that many older women with normal or mildly low bone mass lose density so slowly that frequent rescreening adds little value.
- A new fragility fracture, a high-dose glucocorticoid prescription, or a major health change can justify earlier retesting regardless of the prior interval.
Medicare typically covers bone mass measurement once every 24 months, though it may cover testing sooner, including in some cases after 11 months, when a clinician documents medical necessity, such as monitoring someone on long-term steroid therapy. For a closer look at how these intervals play out by risk category, see this breakdown of DEXA scan frequency.
Limitations and situations that complicate results
DXA is reliable, but a few conditions can skew it. Spine arthritis, compression fractures, or calcified aortic plaque can artificially raise spine BMD readings, while hip implants or prior fracture hardware can make a site unreadable. Patients above a scanner's weight or size limit should call ahead, since some centers can accommodate larger patients while others may need to refer out. Because precision varies by machine, facilities calculate a least significant change value so clinicians can tell real bone loss from normal measurement noise, which is also why repeat scans ideally happen on the same equipment. Peripheral devices and heel ultrasound are useful for initial screening but need confirmation with central DXA before a diagnosis is made.
A practical note on getting tested
If you recognize yourself in the risk factors above, the next move is a conversation with your clinician, not a guess. Bring your checklist and any prior scan reports, and ask directly about the interval that fits your results rather than assuming every two years is right for you. Checking verified scan locations ahead of time makes that first appointment easier to schedule.
— Erik
Finding and booking a DXA scan near you
Comparing clinics before you book saves both time and money. Our platform lists verified DXA locations across the country with transparent cash pricing, so you can see what a scan actually costs before you walk in, no referral required. Before booking, confirm with the clinic that they offer hip and spine DXA (not just a peripheral or body composition scan) and check their equipment's weight limit if that applies to you.
| What to check before booking | Why it matters |
|---|---|
| Scan type offered | Confirm hip and spine DXA, not only body composition |
| Cash price | Compare clinics directly through verified listings |
| Equipment weight limit | Avoid a wasted trip if you're near capacity |
| Referral requirement | Most listed clinics don't require one |
Ready to compare options? Browse bone density test pricing and locations to find a clinic near you.
This article is general information, not a substitute for advice from a qualified doctor. Consult a qualified healthcare professional about your own circumstances before acting on anything here.
FAQ
Can I eat and drink before a bone density test?
Yes, you can eat and drink normally before a DXA scan since fasting isn't required. The only preparation step is avoiding calcium supplements for 24 hours before the exam, since they can interfere with the reading.
What is the average bone density score for a 70 year old woman?
There's no single "average" T-score reported as a standard benchmark, since results vary widely by individual bone health. Population data shows osteoporosis and low bone mass are both common among adults 50 and older, with osteoporosis prevalence higher in women than in men. For context on how density changes across the lifespan, see this guide to bone density by age.
What is the USPSTF's recommendation for bone density screening?
The USPSTF recommends screening all women aged 65 and older, plus younger postmenopausal women whose fracture risk equals or exceeds that of a 65-year-old woman with no other risk factors. Current evidence is insufficient for the USPSTF to issue a routine screening recommendation for men.
What is the recommended frequency for bone density testing?
Testing frequency is individualized, with guideline-based intervals ranging from about 1 year for people starting treatment or at high risk to 3 to 5 years or longer for those with stable, low-risk results. Medicare typically covers testing once every 24 months, with earlier coverage allowed when medically necessary.
Sources
- Medicare
- Radiologyinfo
- Updated practice guideline for dual-energy X-ray absorptiometry (DXA)
- NCHS Data Brief No. 405 — Osteoporosis prevalence (NHANES)