The recently updated product information from OCD indicates that "since the MTS anti-IgG gel card does not contain FDA approved labeling for the detection of IgM antibodies, it is not adequate to demonstrate ABO incompatibility." Somehow the buffered gel card, which contains nothing but buffer, is adequate for the detection of ABO incompatibility. The IgM antibodies in both systems come from patient plasma. I guess the anti-IgG in the anti-IgG card can neutralize or inhibit the IgM antibodies in patient plasma ? OCD reccomends use of their buffered gel card. I'm a bit cinfused.