AOAC CASP Meeting Book

547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570

a level that yields fractional recovery and one nontarget material is analyzed at the growth level achieved in a nonselective broth or at a high inoculation level.

4.1.4.2 Study Design

Minor, reasonable variations in a method of a magnitude that might well be expected to occur when the method is used are deliberately introduced and tested. Variations in method parameters that can be influenced by the end user should be tested. Use a The method developer is expected to make a good faith effort to choose parameters that are most likely to affect the analytical performance and determine the range of variations that can occur without adversely affecting analytical results. Ten replicates of each material are tested for each treatment combination. screening factorial experimental design.

4.1.4.3 Data Analysis and Reporting

The results are analyzed for variable detection due to changes in parameter settings. Report the appropriate statistical measures of the measured variable(s) (e.g., Ct, absorbance, POD value, etc.) for each set of replicates for each treatment combination. This should include at least means, standard deviations, and confidence

intervals where appropriate.

4.2

Independent Validation Study

4.2.1 Scope 571 572 A validation study to corroborate the analytical results obtained by the method developer and 573 to provide additional single laboratory data. The independent validation study traditionally 574 verifies POD in the hands of an independent trained user and is required for PTM or R 2 575 certification and OMA approval. 578 579 If there is a reference method, then the candidate method is compared to a reference 580 method. The reference method should be the same as that used in the Method Developer 581 Study. 584 585 The independent laboratory must test at least one matrix that was tested in the Method 586 Developer Study. The total number of matrices to be evaluated by the independent 587 laboratory is dependent on the claim of the candidate method. For every PTM or R 2 Validation 588 Study, one Independent Study is made by the appropriate method volunteer(s) in consultation 589 with the Study Director and relevant SMPRs. 590 576 577 4.2.2 Reference Method 582 583 4.2.3 Matrices