Variability of Renal Ultrasound Measurements: How Physician Experience and Patient Position Affect Measurement Accuracy?

This study was designed to investigate the variability of renal ultrasound measurements, focusing on the impact of physician experience and patient position. Background: Since decreased kidney length is considered an indicator for chronic renal disease, understanding measurement repeatability and reproducibility is crucial for establishing effective diagnostic guidelines. Methods: Fifty healthy young adults underwent renal ultrasound scans performed by three examiners with varying levels of experience (12 years, 5 years, and 4 weeks). Renal length was measured at the level of the hilum in three patient positions: supine, lateral decubitus, and prone, using a 2–6 MHz convex probe (GE Logiq S8). Results: This study found that examiner experience significantly affected the results of sonographic measurements. However, the Interclass Correlation Coefficient analysis for all examiners demonstrated good reliability in most positions, with the highest values observed for the prone position. Measurements in the lateral decubitus position showed highest values, especially for the most experience examiner. The less experienced sonographers produced more variable results. Conclusions: Standardized patient positioning improves the accuracy and reproducibility of renal ultrasound measurements. The prone position offers a balance of reliability and practicality, especially for less experienced operators.