What does accuracy in DXA refer to?

• A. How consistently measurements are repeated
• B. How close the measurement is to the true value
• C. The reliability of the equipment
• D. The average value of a set of measurements

Answer: (B)

Accuracy in dual-energy X-ray absorptiometry (DXA) specifically refers to how close a measurement is to the true value. When conducting a DXA scan to measure bone mineral density, the goal is to obtain results that genuinely reflect the patient's bone density without systematic errors. A measurement is considered accurate if it aligns closely with the actual bone density of the individual being assessed.

This concept is fundamental in ensuring that treatment decisions based on DXA results are reliable. If measurements lack accuracy, it may lead to misdiagnosis or inappropriate treatment plans. This distinction between accuracy and other measurement characteristics is crucial; for example, while consistency in measurements (as addressed in some other choices) is important for reliability, it doesn't guarantee that those measurements are correct or true. Accuracy is about truthfulness to actual values, making it the essential aspect of the question.