We are receiving a lot of questions about relevant analyses in the Analyse-it Method Validation edition to help in evaluating new diagnostic tests in the fight against COVID-19. Below are some quick links that will help, but contact us if you have questions - we are working as normal.
Also see our latest blog post: Sensitivity/Specificity and The Importance of Predictive Values for a COVID-19 test
Estimate the precision of the measurement procedure at multiple sites and samples.
The worksheet opens showing 4 columns. The Sample column identifies the levels of the analyte in the sample (6 levels). Laboratory identifies the site (3 laboratories), Run identifies the run (5 runs per site). CA19-9 (kU/L) identifies the measured value for 5 replicates of sample in each run.
The analysis report opens.
The variability plots show a simple visual assessment of the closeness of agreement between the measured quantity values. The purple lines show the mean of each run, the light blue lines show the mean of each laboratory, and the dark blue line the overall grand mean.
You should observe the scatter of the points to ensure there are no obvious problems. No individual measurements stand out as highly aberrant relative to the bulk of the data and none of the plots exhibit any apparent drift capable of distorting the results.
The abbreviated variance components table shows the required precision statistics expressed numerically as the standard deviation (SD) and coefficient of variation (CV).
The detailed variance components table show the precision expressed numerically as the chosen measure of imprecision along with a confidence interval for each component.