The requirements for validation of dilution are not clear. Please clarify: If it is sufficient to simply demonstrate the ability to dilute from a concentration at least as high as the highest analyte concentration found in samples down into the standard curve range, or is it necessary to verify the ability to perform at each dilution factor applied. In order to address these points, consideration should be given to 229-231 aligning the recommendations with those in the EMEA guidance. integrity should be demonstrated by spiking the matrix with Proposed change: “Dilution analyte at a concentration above the ULOQ of the assay that is at least equal to the highest anticipated concentration in study samples and diluting this sample with blank matrix using a dilution factor at least equal to the greatest factor to be applied to study samples. Accuracy and precision, based on n 5 determinations, should be within ±15%. “
229-231 The requirements for validation of dilution are not clear. Please clarify: If it is sufficient to simply demonstrate the ability to dilute from a concentration at least as high as the highest analyte concentration found in samples down into the standard curve range, or is it necessary to verify the ability to perform at each dilution factor applied. In order to address these points, consideration should be given to aligning the recommendations with those in the EMEA guidance. Proposed change: “Dilution integrity should be demonstrated by spiking the matrix with analyte at a concentration above the ULOQ of the assay that is at least equal to the highest anticipated concentration in study samples and diluting this sample with blank matrix using a dilution factor at least equal to the greatest factor to be applied to study samples. Accuracy and precision, based on n 5 determinations, should be within ±15%. “
IQ_Comments_on_the_FDA_Draft_Guidance_for_Industry_Bioanalytical_Method_Validation.docx