An ER trauma patient's plasma showed 1+ reactivity in Gel with Screening cell 1 of Immucor's Trio screen. The other two cells were negative. (We buy 3% Immucor screening cells, then dilute them to 0.8% for gel testing.) Using an Ortho 0.8% panel for antibody identification, we found 7 of the 11 cells reacting 1+ with a negative auto control. The reactions did not fit any pattern what-so-ever. Our workup was stopped at that point because the patient was transferred to a larger facility. On follow-up the next day, we found that the other facility had gotten a negative antibody screen, also using Gel cards. Within three hours of performing the antibody screen on the ER trauma patient, the remaining three wells of the gel card were used to perform an antibody screen on another patient. So, the card with the positive Screening cell 1 was spun for another 10 minutes. After the 2nd spin, the reaction had changed to negative. Later, we spun the two cards containing the antibody id with the seven 1+ positive reactions. After the 2nd spin (for a total of 20 minutes) most of the reactions were now negative with the others only questionable, definately not 1+ as after the orginal spin.
I've checked the rpms and timer on the centrifuge, and they are okay. Has anyone else seen positive reactions change to negative after spinning a second time?