EQAS Program User Guide - QCNet

Chapter 6: How to Interpret EQAS ReportsReview the Z-score Trend Charts12Use the Levey-Jennings Chart to review your laboratory’s performance over time. In the example below,you can see a downward trend which indicates a negative bias trend.The Yundt Plot indicates the negative trend is across all concentrations because most of thelaboratory’s Z-score values fall below the zero value line.If your results are consistently different than other laboratories, some logical questions are:• Is my method coded correctly?• Is the difference significant?• Do I need to investigate further?12EQAS Program User Guide 79