Bryan Ballif, University of Vermont (image) University of Vermont Caption Blood banks carefully screen patients and donors by their blood type: A, B, AB, O. They also look for rarer blood types that might lead to transfusion problems. But some blood types remain a mystery. Like Vel. Doctors dread the surfacing of a "Vel-negative." For that patient, transfusion can lead to exploding blood cells, liver failure, and death. Now, using a high-resolution mass spectrometer, UVM biologist Bryan Ballif and colleagues have explained the inner workings of Vel, solving a decades-old blood riddle. Credit Joshua Brown, UVM, 2012 Usage Restrictions with associated article Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.