Using the correct regression analysis technique in method comparison studies

Regression analysis frequently is used to evaluate a new clinical laboratory method. Results from the new method are compared to results from an existing more established method. If measurement error exists in the established method, then least squares may not be an appropriate statistical method to use for the regression analysis. An errors variable regression analysis model was used to evaluate data from five method comparison studies. Results were compared to least squares analyses performed on the same data. When significant measurement error existed in the "reference" method, the errors variable analysis provided a less biased estimate of the regression statistics, which differed markedly from the least squares results. Inappropriate use of least squares in method comparison studies can lead to erroneous conclusions about the relationship of a new analytical method to an existing method.