A Dual-Energy X-ray Absorptiometry (DEXA) scan is the standard procedure for evaluating bone mineral density (BMD), a measurement used to assess bone health and diagnose conditions like osteoporosis. This non-invasive test uses low-dose X-rays to generate precise data about the density of your bones, typically in the hip and spine. Accurate results depend on following preparation guidelines. Ignoring these instructions can lead to skewed measurements, potentially resulting in an incorrect diagnosis or treatment plan.
Why Deodorant is Prohibited During the Test
You must refrain from wearing deodorant, antiperspirant, or any product containing metallic compounds on the day of your DEXA scan. The active ingredients in many of these products, particularly antiperspirants, include dense metallic salts like aluminum chlorohydrate or zinc. A DEXA scan measures how well a substance absorbs the X-ray beam. When these metallic particles are present on the skin, they strongly absorb the X-rays, similar to dense bone tissue.
If metallic residue is in the path of the X-ray beam, the scanner registers this high attenuation as artificially elevated bone density. This interference causes the resulting BMD measurement to be inaccurate. Although the procedure focuses on the central bones of the hip and lower spine, avoiding all potential sources of interference ensures the integrity of the measurement. If you forget to skip your deodorant, some facilities may provide a cleansing wipe to remove any residue before the test begins.
Essential Preparation Steps for Your Bone Density Scan
Other steps are necessary to prepare for your DEXA scan besides avoiding deodorant. It is important to wear comfortable, loose-fitting clothing that is completely free of metal components. This means avoiding items with zippers, snaps, metal buttons, grommets, or underwire in a bra. Any metal near the area being scanned will block the X-rays and create artifacts, which are shadows or bright spots that interfere with the density reading.
Jewelry, including necklaces, earrings, and body piercings that may be in the scan field, should be removed before arriving for your appointment. Managing medication and supplements is also important. You must avoid taking any calcium supplements for at least 24 hours prior to the procedure, as undissolved pills in the stomach can mimic bone density in the scan. If you have recently had an imaging study requiring an oral or intravenous contrast agent, you may need to wait at least seven days before your DEXA scan to ensure the material is fully cleared from your system.