Case 67

1. Prepared by Jordan Ippolito, MLS(ASCP)CM and reviewed by Lorraine Blagg, MA, MLS(ASCP)CMSBB.

Clinical Vignette:
An elderly patient undergoing treatment for multiple myeloma is scheduled for routine surgery. The patient has never been seen at our facility before and has not medical history of transfusion. The patient types as group A, Rh negative with a positive antibody detection test:

A direct antiglobulin test (DAT) was performed and found to be negative for both IgG and complement reactivity. The blood bank technologist repeats the antibody detection assay using commercial red blood cell reagents that have been treated with Dithiothreitol (DTT) and observes the following reactivity:

What do you suspect is causing the reactivity in this patient's sample?