Continuing Education Episode!
Continuing Education!

Red cell antibodies should be simple, right? Not always, and the Mighty Monocyte Monolayer Assay may show the way!

Sandy Nance Monocyte Monolayer Assay

Sandy Nance MS, MASCP, MT(ASCP)SBB

Usually, when a transfusion service or reference laboratory identifies a red cell antibody like anti-K or anti-Fya or anti-D, we know exactly what to do next: Find blood that is negative for the antigen target, and transfuse. Occasionally, though, we find antibodies in patients that come with two distinct problems: First, the antigen target is present on just about every blood donor, so it is hard to find compatible blood, but second, we don’t even know if we NEED compatible blood! Some people with antibodies like “anti-Yta” or “anti-Vel” will hemolyze transfused blood carrying the antigen, while others just don’t! We call these things “antibodies of variable clinical significance,” and they lead to the very important question, “Do we search the world for rare units of compatible blood, or can we just transfuse ABO-compatible red cells out of our regular inventory?

The Mighty MMA Shows The Way!

Back in the 1980’s, blood bankers were using many different tests to try to answer that question, but many of those tests were complex and logistically challenging. Sandy Nance and a group of other illustrious scientists at the American Red Cross developed the monocyte monolayer assay to try to help us with the choice of whether or not a patient with an antibody against a high-frequency antigen can be safely given antigen-positive blood. The MMA is simple in concept, but labor-intensive, so not very many labs do it, and you may or may not have heard of it. After today, I think you will have a much better understanding of what the test is, and how it can really help in some “no-win” situations.

Sandy Nance Monocyte Monolayer Assay

Sandy Nance MS, MASCP, MT(ASCP)SBB

Usually, when a transfusion service or reference laboratory identifies a red cell antibody like anti-K or anti-Fya or anti-D, we know exactly what to do next: Find blood that is negative for the antigen target, and transfuse. Occasionally, though, we find antibodies in patients that come with two distinct problems: First, the antigen target is present on just about every blood donor, so it is hard to find compatible blood, but second, we don’t even know if we NEED compatible blood! Some people with antibodies like “anti-Yta” or “anti-Vel” will hemolyze transfused blood carrying the antigen, while others just don’t! We call these things “antibodies of variable clinical significance,” and they lead to the very important question, “Do we search the world for rare units of compatible blood, or can we just transfuse ABO-compatible red cells out of our regular inventory?”

The Mighty MMA Shows The Way!

Back in the 1980’s, blood bankers were using many different tests to try to answer that question, but many of those tests were complex and logistically challenging. Sandy Nance and a group of other illustrious scientists at the American Red Cross developed the monocyte monolayer assay to try to help us with the choice of whether or not a patient with an antibody against a high-frequency antigen can be safely given antigen-positive blood. The MMA is simple in concept, but labor-intensive, so not very many labs do it, and you may or may not have heard of it. After today, I think you will have a much better understanding of what the test is, and how it can really help in some “no-win” situations.

093CE monocyte mononuclear assay

About My Guest:

Sandy Nance is the emeritus Senior Director for National Laboratories for the American Red Cross and has provided leadership to multiple programs at the Red Cross and blood bank world in general, including the American Rare Donor Program and the national American Red Cross SBB Program. She is also an emeritus Adjunct Assistant Professor at the University of Pennsylvania, Division of Transfusion Medicine & Therapeutic Pathology Department of Pathology and Laboratory Medicine. She has a master’s degree in Pathology from the University of Maryland and received her SBB from the Johns Hopkins Medical Institutions. Sandy developed of the use of polyethylene glycol or PEG for serologic testing as well as today’s topic, the monocyte monolayer assay (MMA).

Sandy’s list of honors and awards is too long to detail, but they include the John Elliott, President’s, and Sally Frank awards from AABB, the National Blood Foundation Hall of Fame, the ASCP Hall of Fame. She has authored or co-authored over 45 scientific papers and 200 abstracts, and edited 9 books.

Her career positions include Lead Technologist at Johns Hopkins Medical Institutions with Dr. Paul Ness and Immunohematology Research Associate in Dr. George Garratty’s Research Laboratory. Active in education, she has been faculty for University of Maryland, Johns Hopkins Medical Institutions, University of Pennsylvania, NIH and American Red Cross.

FREE Continuing Education!

This podcast episode offers a FREE continuing education activity where you can earn the following types of credit: 1 AMA PRA Category 1 CreditTM, and 1 ASCLS P.A.C.E.® Contact Hour (including Florida Clinical Laboratory Credit). This activity also may be used to fulfill Lifelong Learning Continuing Certification requirements for the American Board of Pathology.

To receive credit and review the accreditation information and related disclosures, please visit Transfusion News Continuing Education on Wiley Health Learning.

DISCLAIMER: The opinions expressed on this episode are those of my guest and I alone, and do not reflect those of the organizations with which either of us is affiliated. Neither Sandy nor I have any relevant financial disclosures.

The images below are generously provided by Sandy Nance.

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Further Reading:

Thanks to:

Music Credit

Music for this episode includes “Cuando te invade el temor” and “Reflejo,” both by Mar Virtual via the Free Music Archive. Click the image below for permissions and license details.
Creative Commons license and link

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