This downloadable file contains the proceedings of the AACC webinar “Understanding and Managing Lot-to-Lot Variation in Immunoassays,” held October 26, 2011. What causes the discordance that sometimes occurs between QC results and patient results when validating a new lot of reagents? How much variation should be “allowable” when a new lot is introduced? Learn the answers to these questions and more. During this program, presenters explain why QC alone is inadequate for evaluating the impact of a change in reagent lot; what regulatory agencies and accrediting organizations require labs to do when validating a new reagent lot; and how one lab director determines the “allowable” variation when switching to a new reagent lot. The experts also outline strategies for “troubleshooting” problems when introducing a new reagent lot and describe additional steps for validating new reagent lots in special cases (like troponin) where there are very specific recommendations for measuring an analyte and reporting results.