BACKGROUND: When assessing the agreement of two methods, the simple correlation coefficient, the most frequently used but easy to cause misleading interpretation of results, is still comprehensively adopted in journals of clinical chemistry or diagnostic laboratory. This study is aimed at comparing the correlation coefficient with the alternative method, which came from FDA recommended guidance for waiver assays--Allowable Total Error (ATE)/Limits for Erroneous Results (LER) zones, and fully addressing the applicable conditions of the later one. METHODS: The data we use were both real and simulated data to calculate correlation coefficient and ATE/LER zones, respectively, when assessing the agreement. And a modified ATE/LER zones method was brought forward to assess the agreement of repeated measurements and the repeatability of each single method. RESULTS: The high correlation can only indicate that the two methods are linearly related rather than in agreement with each other. However, the ATE/LER zones can avoid this shortcoming by using certain statistical strategies considering the clinical judgment. The modified method is suitable to evaluate the repeatability of single method and the agreement of repeated measurement by two measuring methods. CONCLUSION: The ATE/LER zones method is a relatively reasonable and widely considering method for assessing the agreement.
BACKGROUND: When assessing the agreement of two methods, the simple correlation coefficient, the most frequently used but easy to cause misleading interpretation of results, is still comprehensively adopted in journals of clinical chemistry or diagnostic laboratory. This study is aimed at comparing the correlation coefficient with the alternative method, which came from FDA recommended guidance for waiver assays--Allowable Total Error (ATE)/Limits for Erroneous Results (LER) zones, and fully addressing the applicable conditions of the later one. METHODS: The data we use were both real and simulated data to calculate correlation coefficient and ATE/LER zones, respectively, when assessing the agreement. And a modified ATE/LER zones method was brought forward to assess the agreement of repeated measurements and the repeatability of each single method. RESULTS: The high correlation can only indicate that the two methods are linearly related rather than in agreement with each other. However, the ATE/LER zones can avoid this shortcoming by using certain statistical strategies considering the clinical judgment. The modified method is suitable to evaluate the repeatability of single method and the agreement of repeated measurement by two measuring methods. CONCLUSION: The ATE/LER zones method is a relatively reasonable and widely considering method for assessing the agreement.