Malcolm, We recently had a patient that had a previous WAA that returned 5 years later. Antibody screen is negative. Would you still give phenotipically matched packed cells? If we have a patient with no history at our facility and a negative screen, how do we know that they didn't have a previous WAA ?? If we get a negative screen, we say hooray and move on. This topic has caused some debate at our facility. Thank you for your input!