Table 2. Comparison of independent measurements.

Measurement	Mean difference	Lower limit of agreement (95%CI)	Upper limit of agreement (95%CI)
Base	−1.47	−7.23 (−8.21, −6.24)	4.29 (3.30, 5.27)
2 cm	−1.58	−7.44 (−8.44, −6.43)	4.28 (3.28, 5.29)
4 cm	−0.67	−4.55 (−5.22, −3.89)	3.22 (2.55, 3.88)
6 cm	−0.64	−3.01 (−3.41, −2.60)	1.73 (1.33, 2.14)
8 cm	−0.69	−3.74 (−4.28, −3.20)	2.37 (1.83, 2.91)
10 cm	−0.90	−3.23 (−3.65, −2.82)	1.43 (1.01, 1.85)
15 cm	−0.54	−2.54 (−2.92, −2.16)	1.47 (1.09, 1.85)
Midshaft	−0.79	−3.84 (−4.43, −3.25)	2.26 (1.67, 2.85)

CI, confidence interval.