We have had two ABS2000 instruments for many years. Late last year we noticed an increase in invalid results and the number of invalid results has continued to increase to the present time. Immucor service has worked on the instruments several times during this time period, replaced readers, other parts but to no availe. We have been told by Immucor for some time that the control cells are the problem. Regarding shipping, this certainly could be part of the problem but since we have been having the problem for many months, probably not the root cause. Immucor seems unable to correct the problem. At times, the problem has been significant enough for the techs to go on manual solid phase in lieu of utilizing the instruments. David Linnemeyer MT(ASCP)SBB New Orleans