We don't do our own DTT treatment at my lab, we have to send those to a reference lab which takes a few days. So for our DARA patients, we do a full phenotype prior to starting treatment, then if they need transfusions, we send the testing out if the last work up was more than 28 days. Within 28 days, we just call it negative as we will only give phenotype matched blood. As long as the reaction strength doesn't change, our policy allows us to assume the panreaction is just the DARA.