An Overview and 40 Year Summary of the Monocyte Monolayer Assay at theAmerican Red Cross/Titer Controls

Course overview

The Monocyte Monolayer Assay (MMA) is a key tool for assessing redcell alloantibodies and guiding transfusion decisions. This session reviews its origins, explains principles and methodology, and presents case studies demonstrating clinical impact. We will clarify common misunderstandings, examine recent trends in MMA ordering and utilization, and identify antibodies most often evaluated. Practical guidance for laboratory professionals and physicians will cover when to recommend the MMA, collaboration between hospitals and reference labs, and operational steps to integrate the assay into routine transfusion practice. This presentation provides an overview of CMS regulatory requirements for titer quality control and their application within immunohematology laboratories. It reviews AABB IRL Standards, clarifies expectations for serial and point-dilution titers, and explains appropriate QC materials, methodology alignment, and testing frequency. CMS guidance and real-world scenarios are used to illustrate how laboratories can ensure accuracy, consistency, and compliance in titer testing practices