Avoid These Costly Mistakes Before Your DEXA Bone Scan for Accurate Results

A patient lies still on a DXA (DEXA) scanning table during a bone density test. Proper preparation is key to ensuring accurate results from a DEXA scan.
Getting a DEXA bone scan (also known simply as a DXA scan or bone density test) is an important step in assessing your bone health, body composition, or risk of osteoporosis. The good news is that preparing for a DEXA scan is relatively simple – there are just a few key things you should never do before your appointment to ensure the scan is accurate and safe. In this article, we’ll explain what a DEXA scan is, why preparation matters, and break down the top things to avoid before your DEXA scan. These tips will help you get the most accurate results while keeping the process smooth and stress-free.

What Is a DEXA Bone Scan?

A DEXA bone scan (dual-energy X-ray absorptiometry) is a specialized X-ray test that measures your bone mineral density and can also assess body composition. It’s commonly used to diagnose osteoporosis or osteopenia, and to evaluate body fat and muscle mass distribution for fitness or health monitoring. During the scan, you lie on a padded table while a scanning arm passes over your body. The scan is quick (about 10 – 20 minutes) and completely painless, using very low-dose X-rays to capture images of your bones and tissues.
The result is a detailed report on your bone density (often given as a T-score) and potentially your body fat percentage and lean mass, depending on the type of DEXA analysis. In short, a DEXA scan is the gold standard for measuring bone density and is a valuable tool for guiding treatment or tracking progress in bone health and fitness.
Why does proper preparation matter? If you don’t follow certain guidelines before a DEXA scan, you might get skewed results or even need to reschedule the test. Eating or doing certain things can temporarily alter your body’s composition or interfere with the X-ray images, leading to inaccurate readings. By avoiding the “no-nos” listed below, you’ll ensure that your bone density readings are as precise as possible and that the procedure goes off without a hitch. Now, let’s look at what you should never do in the day or two leading up to your DEXA bone scan.

Key Things to Avoid Before a DEXA Scan

Even though a DEXA scan generally requires little special preparation, there are a few important precautions. Here are the top things you should never do before getting a DEXA scan, and why skipping them will help you get accurate results:

1. Don’t Take Calcium Supplements or Antacids Right Before

Avoid taking any calcium supplements, multivitamins, or antacid tablets (like Tums) for at least 24 hours before your DEXA scan. Calcium supplements can linger undissolved in your stomach and may show up on the scan as extra bone density, which can throw off your results. Medical experts universally recommend not taking calcium pills or vitamin tablets the day before and day of your scan. You can still eat your normal diet, including foods that contain calcium – just skip the pills or fortified drinks prior to the exam.
If you’re unsure about a specific supplement or medication, check with your healthcare provider. The bottom line: never pop a calcium pill the night or morning before your DEXA. It’s an easy thing to avoid, and it ensures your bone density measurement will be accurate, not artificially high due to a calcium tablet in your GI tract.

2. Never Schedule Your DEXA Right After a Contrast Imaging Test

If you’ve recently had another medical imaging procedure that involved contrast dye (for example, a CT scan with contrast, a barium swallow, or a nuclear medicine scan), do not rush to get a DEXA scan immediately after. The residue from contrast agents can interfere with DEXA results, so timing is important. Doctors advise that you may need to wait anywhere from 24 hours up to 10 – 14 days after a contrast imaging study before doing your DEXA, depending on the type of contrast used.
For instance, barium from a GI study can remain in your system and affect the X-ray readings of the DEXA. To be safe, never get a DEXA scan within at least a week of any procedure involving contrast dyes. Always inform your doctor or the DEXA technician about recent scans or injections of contrast material. They might simply reschedule your bone density test to a later date to ensure any contrast is out of your body. Being honest about your recent medical tests will help you avoid an unnecessary repeat DEXA or misleading results.

3. Don’t Wear Clothing with Metal (and Remove All Jewelry)

What you wear to your DEXA scan matters. Metal objects can block X-rays or appear on the images, so you should never show up to a DEXA exam wearing clothes with metal fasteners. That means avoid pants or jackets with metal zippers, buttons, buckles, or metallic threads, and skip clothing with underwire bras or metal hooks as well. Opt for loose, comfortable attire like sweatpants, leggings, T-shirts, or activewear without any metal.
You will also be asked to remove all jewelry and metal accessories before the scan. Items such as watches, rings, necklaces, bracelets, body piercings, and even eyeglasses should be taken off so they don’t interfere with the X-ray. It’s best to leave valuables at home to avoid misplacing them. If you have non-removable jewelry or metal (like a medical implant), inform the technician – small pieces of metal usually do not affect a bone density scan significantly. In summary, never wear metal to a DEXA scan. Arrive in metal-free clothing and be prepared to empty your pockets. This way, the scan can clearly detect your bones without anything blocking the view.

4. Never Eat a Huge Meal Right Before the Scan

Unlike some medical tests, you do not need to fast before a DEXA scan – however, it’s wise to avoid eating a heavy meal in the hour or two leading up to your appointment. A large meal (especially one high in salt or carbohydrates) can temporarily increase your weight and water retention, which might slightly skew your body composition readings. For example, a big lunch might leave food and fluid weight in your stomach and intestines that the scan could mistake as lean mass or fat mass, potentially affecting the accuracy.
As one DEXA provider put it, “we want to measure you, not what’s in your gut!”. To play it safe, don’t go for an “all-you-can-eat” feast right before stepping on the DEXA table. If you’re hungry, a light snack or meal is perfectly fine – just avoid overeating immediately before your scan. This is especially relevant if you’re doing a body composition DEXA, where even small changes in hydration or stomach contents can alter the readout slightly. Plan your meals so that you’re comfortable (not starving, but not overly full) at the time of the test.

5. Don’t Overhydrate or Arrive Dehydrated (Stick to Normal Fluids)

Hydration can affect your body composition measurements, so it’s important to maintain your normal fluid intake before a DEXA scan. Never deliberately chug huge amounts of water right before your scan, and conversely, don’t dehydrate yourself either. Overhydrating could make you feel bloated and might increase your lean mass reading slightly due to extra water weight, while being dehydrated could conceivably concentrate your body tissues and alter the readings in the opposite direction.
The best approach is to drink water as you normally would, and simply avoid any extreme intake immediately prior. For instance, don’t down a giant 1-liter bottle of water in the waiting room; but also don’t skip drinking all day. According to experts, you should be “normally hydrated” and just drink enough to stay comfortable – not excessively much and not too little. It’s also a good idea to avoid large amounts of coffee or soda right before the scan, as these might act as diuretics or cause bloating. A sensible tip is to use the restroom to empty your bladder before the scan begins. Overall, keep your fluid intake routine and moderate before your DEXA. This way your results won’t be thrown off by water weight fluctuations.

6. Avoid Strenuous Exercise on the Day of the Scan

While exercise is great for your health and bones, you should not do vigorous workouts in the hours leading up to your DEXA scan. Never hit the gym right before a DEXA appointment, as tempting as it may be to squeeze in a workout. Intense exercise (cardio or weightlifting) can affect your hydration status (through sweat loss and subsequent rehydration) and cause a “pump” in your muscles that alters their fluid content and size temporarily. This can lead to misleading body composition readings – for example, your lean mass might read higher or lower than normal depending on how much you sweated and replenished fluids.
One research study found that exercising shortly before a DEXA scan could skew the results by as much as 10%, which is quite significant. The study suggests it’s more accurate to simply wait until after your scan to exercise, rather than trying to adjust food or water around a workout. To ensure consistency, many professionals recommend avoiding hard exercise for at least 4 hours prior to the scan and to arrive for your DEXA calm and well-rested. Light daily activities are fine, but save the gym session for after your DEXA. This way, your muscles won’t be engorged and your body will be in a normal, rested state for the most accurate measurement.

7. Don’t Get a DEXA Scan If You Might Be Pregnant

DEXA scans use X-rays, and although the radiation dose is extremely low, it’s generally not recommended to undergo a DEXA scan during pregnancy (unless absolutely necessary for a medical reason). If you are pregnant or suspect you might be, never have a DEXA scan without discussing it with your doctor first. In fact, healthcare providers will usually ask women if there’s any chance of pregnancy and cancel or postpone the exam if so. The Cleveland Clinic explicitly advises: “You shouldn’t have a bone density test if you’re pregnant… if you’re pregnant you should avoid all forms of radiation if possible.”. The rationale is that even a tiny radiation exposure that is safe for an adult could be unnecessary for a developing fetus.
Therefore, to be safe, pregnant women should not get a DEXA scan – or at the very least, they should inform the technician so extra precautions can be taken. If you find out you’re pregnant after scheduling a DEXA, simply call to reschedule for after your delivery. Your bone health test can wait, and it’s not worth any potential risk (no matter how small) to a pregnancy. In summary: never undergo a DEXA if pregnant – always inform your healthcare provider and choose an alternative or delay the scan.

8. Never Skip Your Regular Medications (Unless Advised)

Aside from the specific items mentioned above (like calcium supplements), you generally do not need to stop any prescribed medications before a DEXA scan. In fact, it’s important that you do not suddenly skip your routine medications on the day of your scan unless your doctor has told you to. The DEXA test itself isn’t affected by most medicines. Continue taking your usual medications as prescribed – for example, blood pressure pills, insulin, thyroid meds, etc., can all be taken normally on scan day.
The only exceptions would be if your doctor specifically instructs you to hold a medication (which is uncommon for a bone density test, aside from calcium/vitamin supplements discussed earlier). Skipping important meds could be harmful to your health or make you feel unwell during your appointment. So, never withhold your regular medications on your own. When in doubt, ask your physician ahead of time. But by and large, keep your medication schedule unchanged leading up to a DEXA scan. This ensures you remain in your usual state of health, which is exactly what we want to capture during the bone density test.

Making the Most of Your DEXA Scan Experience

By avoiding the pitfalls above, you’ll be set up for a smooth and accurate DEXA scan. In summary, stick to your normal routine (eat normally, take your usual meds) but don’t take calcium supplements, don’t wear metal, don’t overeat or over-drink right beforehand, and hold off on intense workouts for a bit. A DEXA scan is a quick, painless test, and with the proper prep, it provides invaluable information about your bone health and body composition.
What happens when you follow these guidelines? On the day of the scan, you’ll check in and likely be asked to remove any metal items. You’ll then lie on the scanning table, usually fully clothed in your comfy metal-free attire, and remain still while the machine scans your hip, spine, or sometimes your full body. The process only takes about 10 – 20 minutes, after which you can go about your day normally. Your doctor or technician will analyze the results and explain your bone density scores (for example, your T-score, which compares your bone density to that of a young adult). If anything abnormal is found, you can discuss next steps, such as lifestyle changes or treatments to improve your bone strength.

Push Pounds Physiotherapy Perspective (Neutral Overview)

At Push Pounds, we understand the importance of accurate assessments in guiding your health and fitness journey. A DEXA scan’s results can inform your physiotherapy plan, nutrition strategy, or exercise program by revealing key data about your bone density and body composition. Push Pounds offers advanced DEXA body composition testing in a professional setting, ensuring that clients get precise measurements in a comfortable environment.
Our team emphasizes proper preparation – as outlined above – so that each scan reflects your true baseline and progress. While we maintain a neutral, client-centered approach, we integrate tools like DEXA scanning into our wider sports medicine and rehabilitation services to help you make informed decisions about your health. If you have any questions about whether a DEXA scan is right for you, how to prepare, or how to interpret your results, the experts at Push Pounds are here to help. With the right prep and professional guidance, a DEXA bone scan can be a powerful piece of your overall wellness puzzle, from preventing osteoporosis to tracking body composition changes over time.

TL:DR

A DEXA bone scan is one of the best ways to get a snapshot of your bone health, but a few simple precautions will ensure that snapshot is crystal clear. Never do the eight things we discussed before your scan, and you’ll maximize the accuracy and usefulness of your DEXA results. With this knowledge in hand, you can confidently schedule your bone density test, follow the prep tips, and be on your way to gaining valuable insights about your body. Whether you’re a patient checking on osteoporosis risk or an athlete measuring your training progress, following these guidelines will help you get the most out of your DEXA scan – and keep your bones moving strong for years to come!