What does precision in DXA refer to?

• A. The accuracy of a single measurement
• B. The reproducibility of repeated measurements over time
• C. The trend of results over multiple scans
• D. The variability between different machines

Answer: (B)

Precision in Dual-energy X-ray Absorptiometry (DXA) refers to the reproducibility of repeated measurements over time. It measures how consistent the results are when the same test is conducted under the same conditions multiple times. This is crucial in bone densitometry because clinicians rely on consistent measurements to monitor changes in bone density, assess the effectiveness of treatments, and make informed decisions about patient care.

In the context of DXA, high precision ensures that the variations between repeated scans are minimal, indicating that the scanning process and analysis yield stable and reliable results. If precision were low, it could lead to uncertainty about the actual changes in bone density, potentially affecting patient management adversely.

Other aspects like accuracy, trends over multiple scans, and variability between different machines do not encompass the definition of precision, which specifically pertains to the consistency and reliability of measurements rather than their correctness or their comparison across different contexts.