To achieve a statistical confidence in BMD measurements, what is the calculated Precision Error (PE) for a 1% rate of change?

• A. 1.5%
• B. 1.7%
• C. 2.0%
• D. 2.5%

Answer: (B)

In the context of bone densitometry, the Precision Error (PE) represents the reliability and consistency of bone mineral density (BMD) measurements. It is crucial for establishing statistical confidence in the changes detected over time.

For a 1% rate of change, a Precision Error of approximately 1.7% indicates that any observed change must exceed this threshold to be considered statistically significant. This level of precision is appropriate for ensuring that minor fluctuations in BMD measurements are accounted for, allowing for meaningful clinical interpretations of changes within a patient’s bone density from one assessment to another.

The 1.7% figure strikes a balance between sensitivity and specificity in detecting real changes in BMD, thus ensuring that clinicians can make well-informed decisions based on the data collected. Precision is fundamental in bone densitometry because the goal is to identify significant changes that could indicate a progression or improvement in a condition such as osteoporosis rather than random measurement variability.