The bone density test, most commonly performed as a dual-energy X-ray absorptiometry (DEXA or DXA) scan, is a simple, non-invasive imaging procedure. This test accurately measures bone mineral density (BMD), a metric that helps physicians diagnose osteoporosis and assess a person’s risk of future bone fractures. Preparing correctly for the DEXA scan ensures the most accurate reading of your bone strength, which is fundamental for guiding any necessary treatment plan. Understanding the necessary steps beforehand will provide reliable data for your healthcare provider.
Pre-Appointment Dietary and Medication Adjustments
You must make specific adjustments to certain supplements and medications before your scheduled DEXA scan to prevent interference with the results. The most important preparation involves calcium, which the scan is designed to measure within your bones. Therefore, you should avoid taking any calcium supplements for at least 24 hours before your appointment, with some facilities recommending up to 48 hours.
This restriction applies to all calcium-containing products, including over-the-counter antacids like Tums, and any multivitamins that list calcium as an ingredient. Ingesting calcium shortly before the scan could create a falsely high density reading, skewing the overall measurement of bone mineral density. Normal eating and drinking is permitted, and fasting is not necessary before the test. However, if you are taking a prescription osteoporosis medication, consult with your prescribing physician about whether to hold the dose on the morning of the test.
Handling Recent Medical Procedures
Recent medical imaging procedures can interfere with the accuracy of the DEXA scan, requiring a waiting period before your appointment. This is related to the presence of contrast material, which can linger in the body and mimic dense tissue on the X-ray images. Contrast agents are used in procedures such as barium studies, CT scans with contrast dye, or radioisotope scans in nuclear medicine.
You must wait a specific period after these tests—usually between seven and fourteen days—to ensure the contrast material has fully cleared your system. If you have had any such procedure recently, inform the scheduling staff or your doctor, as rescheduling your DEXA scan may be necessary. The presence of these agents can skew the results, making it impossible to accurately measure bone mineral density.
What to Wear and Bring on Test Day
Physical preparation involves choosing the right attire and gathering necessary documentation. Select loose-fitting, comfortable clothing that does not contain any metal components. Avoid items with metal zippers, snaps, buttons, belts, or underwire bras, as metal objects interfere with the X-ray beam and create artifacts on the image.
All personal metallic items must be removed before the scan begins, so leave jewelry, watches, and body piercings at home. Bring a photo identification card, your insurance card, and the doctor’s referral or prescription for the DEXA scan. Having these documents ready will streamline the check-in process.
Understanding the Testing Procedure
The DEXA scan is a straightforward, non-invasive process that is quick and painless. Upon entering the exam room, you will lie down on a padded table, typically on your back. You must remain as still as possible during the scan, as movement can blur the images and compromise the accuracy of the measurement.
The machine’s imaging arm slowly passes over the areas being scanned, most commonly the lower spine and the hips. These sites provide the most relevant data on fracture risk. The entire scanning portion usually takes about 10 to 20 minutes to complete. After the scan is finished, a radiologist interprets the images and generates scores, such as the T-score, which compares your bone density to that of a healthy young adult. These results are sent to your referring physician, who will discuss the findings and any follow-up treatment.