Assessing Agreement Between Two Methods

Through preliminary experiment, we obtain the mean and standard deviation of the differences between AIA-1800 and I2000 methods of 0.001167 mmol /l and 0.001129 mmol / l. If we define α=0.05, β=0.20, (− δ.δ)=(− 0.004.0.004) mmol/l, we can calculate that a sampling size of 83 would be required to provide 80% power to assess conformity between two measurement methods. The Monte Carlo simulation is used to obtain the corresponding power, which corresponds to 80.51%, close to the predefined power (80%). Table 1 can be a reference for clinical researchers to estimate the sample size in the conformity assessment study between two measurement methods. Sample size(s) for the Bland Altman method with non-centralized t-distribution for different standardised difference limits (μ/σ), different standardised conformity limits (δ/σ) and Type II errors (β). (α=0.05).