How to Prepare for a Bone Density (DXA) Scan: A UK Checklist

Preparing for a bone density scan is refreshingly simple — there is no special diet, no needle and no lengthy build-up. Most of the "preparation" is really just a short checklist so the images come out clean and the appointment runs on time. This guide walks through what to wear, what to pause, and what to tell the team, drawing on the Royal Osteoporosis Society and NHS trust patient information. At the end, we explain how preparing for a Screen My Bones assessment day differs.

What should I wear for a bone density scan?

Wear loose, comfortable clothing with no metal on it. Metal fastenings sit in the path of the scanner and can distort the X-ray image, so the standard advice is to leave the zips, buckles and buttons at home. The Royal Osteoporosis Society specifically advises avoiding clothes with metal objects such as zips, heavy buttons, fasteners, belts or underwired bras Royal Osteoporosis Society, 2026. UK NHS trusts extend the same list to studs, hooks and jewellery — University Hospitals of Leicester asks patients to remove zips, fasteners, studs, hooks, buttons, girdles and underwired bras University Hospitals of Leicester NHS Trust, 2025, while University Hospital Southampton suggests loose comfortable clothing and avoiding a heavily studded pair of jeans or an underwired bra University Hospital Southampton NHS Foundation Trust, 2022.

The good news is that you usually stay dressed for the whole thing. You are only asked to change into a hospital gown if what you are wearing contains metal that would affect the results — for example jeans with a zip or an underwired bra Royal Osteoporosis Society, 2026. Choosing a soft top and elasticated trousers or leggings usually avoids the gown altogether.

Should I stop taking calcium supplements before a DXA scan?

Only if your clinic asks — some do, many don't. This is the one preparation step that genuinely varies, so it's worth checking your appointment letter rather than assuming. Cleveland Clinic advises not taking calcium supplements or other over-the-counter vitamins in the 24 hours before the test Cleveland Clinic, 2026, and RadiologyInfo similarly recommends not taking calcium supplements for at least 24 hours before the exam RadiologyInfo.org (RSNA and ACR), 2026. The reasoning is that undissolved calcium in the gut can occasionally overlap the spine on the image and nudge the reading.

Notably, the UK patient leaflets we reviewed from the Royal Osteoporosis Society and two NHS trusts did not mention calcium supplements at all — so this is not a universal rule. If in doubt, ask when you book. Pausing a supplement for a day is different from changing your diet, and you can usually still eat calcium-rich foods as normal.

Can I eat, drink and take my medicines before the scan?

Yes — a DXA scan needs no fasting and no changes to your routine medicines. You can eat and drink as usual before you arrive; there is no requirement to turn up on an empty stomach. The Royal Osteoporosis Society confirms you can eat and drink normally and that you do not need to stop taking any of your medicines for the scan Royal Osteoporosis Society, 2026.

The only supplement that sometimes comes with an instruction is calcium, covered above — and that is about the supplement pill, not your prescription medicines.

What should I tell the team before my bone density scan?

Two things: recent contrast or nuclear-medicine scans, and pregnancy. Both are about getting an accurate, safe result, and both usually lead to rescheduling rather than cancelling.

First, flag any recent imaging that used a dye or radioactive tracer. Contrast agents and isotopes can linger in the body and interfere with a bone density reading. RadiologyInfo advises telling your physician about a recent barium exam, or contrast for a CT or radioisotope scan, and notes you may have to wait 10 to 14 days before a DXA RadiologyInfo.org (RSNA and ACR), 2026. The exact window differs by service — University Hospital Southampton asks you to contact them if you have had an isotope scan or barium X-ray in the last two weeks University Hospital Southampton NHS Foundation Trust, 2022, while Leicester references the last three weeks University Hospitals of Leicester NHS Trust, 2025. The practical point is simply to mention it — the team will advise on timing.

Second, tell the team if you are, or might be, pregnant. A DXA scan uses X-rays, and X-rays are not recommended in pregnancy because they can affect an unborn baby, so the scan is rearranged for after your pregnancy NHS, 2026Royal Osteoporosis Society, 2026. This caution is standard across NHS DXA services University Hospital Southampton NHS Foundation Trust, 2022.

Do I need to arrive at a particular time?

Yes — arrive on time, because DXA appointments are booked in short back-to-back slots. These scans move quickly, so departments schedule them tightly. University Hospitals of Leicester books patients roughly every 15 to 20 minutes and warns that if you arrive late you may have to be rebooked for another day University Hospitals of Leicester NHS Trust, 2025. Building in a few minutes' buffer means a small delay doesn't cost you the appointment. If you know you're going to be late, phone ahead.

Is a DXA scan painful, and how long does it take?

No, it isn't painful — and it's quick. There is no injection and no enclosed tunnel. You simply lie on your back on an open scanning table while a mechanical arm passes over your body; you won't feel anything during the scan itself Royal Osteoporosis Society, 2026. The NHS describes the scan as quick and painless NHS, 2026.

The scanning part takes only a few minutes — at University Hospitals of Leicester, each area takes about a minute, with two areas (usually the hip and spine) commonly measured University Hospitals of Leicester NHS Trust, 2025. Including check-in and having your height and weight recorded, the whole appointment is usually completed within about 10 to 30 minutes RadiologyInfo.org (RSNA and ACR), 2026. If you'd like a fuller breakdown, see our guide on how long a bone density scan takes.

The radiation dose is very low: University Hospital Southampton likens it to a few hours of natural background radiation University Hospital Southampton NHS Foundation Trust, 2022, and Leicester to about a day of background radiation University Hospitals of Leicester NHS Trust, 2025 — small, but the reason pregnancy still means rescheduling.

How is preparing for a Screen My Bones assessment day different?

It's simpler, because there are no X-rays to plan around. Screen My Bones assessment days use REMS, a radiation-free ultrasound bone assessment, rather than DXA. That removes the one preparation concern that DXA carries for some people — the X-ray-related pregnancy restriction does not apply to a radiation-free ultrasound in the same way, and there is no dye or tracer involved.

The everyday basics still make your visit smoother: wear loose, comfortable clothing you can move in, and turn up at your booked time. You attend a mobile assessment-day pop-up rather than a hospital imaging department, so there's no lengthy referral pathway to navigate. You can read what a visit involves in our guide to what to expect at a screening day, or see the detail of our bone health assessment.

If you're weighing up your options, the preparation checklist above applies to any DXA scan you book through the NHS or privately; for a radiation-free alternative, you can book a Screen My Bones assessment and we'll confirm everything you need to bring.

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This article is part of our screening technology series. To understand the two main scan types side by side, see our comparison of REMS vs DEXA.