I *almost* posted this on the thread of a similar title with the mixed media, but that seemed to address media (gel vs. tubes) and was less about the two tests. The problem we've had in our lab is very occasionally we'll have a positive autocontrol and a negative DAT/AC3. We've a tech who simply does not believe this is possible and has taken to repeating the testing the following day after the specimen has been in the fridge overnight and then changing the results (triggering a corrected report and contacting the doctor). Aside of the obvious issues regarding interpersonal conflict, consistency in reporting and so on... my question is: are the original results possible? She is so insistent that I'm second guessing myself here. That is: can you have a positive autocontrol and a negative DAT? I've been looking through the web and the AABB tech manual and not finding anything really definitive that addresses this directly. Again, all the testing is in tubes, so this isn't an issue of comparing different media types. This came to a head today where I got a 4+ auto for a RT/4C screen and ran a regular DAT and got a negative result. I attributed this to some nonspecific, clinically insignificant CAA. Can someone direct me to a resource that can help provide some guidance on this? Thanks in advance!