Problem in the use of two- versus four-cell screens in detection of certain antibodies when using the ABS 2000 system
A transfusion medicine pathologist in Missouri reports that his laboratory has recently purchased and is currently validating an Immucor ABS 2000 device for use in blood bank testing (CAP Today, Oct. 2002).
During their validation process they have begun to use a '4-cell screen' in an attempt to maintain a level of sensitivity for antibody detection that they feel is nearly comparable to their previous 'tube' and 'manual solid phase' testing methods. They noticed an improvement in antibody detection sensitivity when they switched from a '2-cell screen' to a '4-cell screen' especially for antibodies like anti-Jka. However, for some reason, they have had some difficulty detecting certain examples of anti-K, even when using a 4-cell screen. The inquiring colleague wonders if other ABS 2000 users have chosen to use a 4-cell screen rather than a 2-cell screen to improve on test sensitivity, and if so, have they had problems detecting some examples of anti-K, or other significant antibodies.
The following responses have been received.
ADDENDA Apr. 29, 2004
- A colleague in Texas reports that at his hospital in Dallas they have three ABS 2000's on which they perform approximately 4300 antibody screens/month. The Texas colleague is of the opinion that they have not lost sensitivity for detecting alloantibodies by using an ABS 2000, based on an inhouse study in which they did parellel tube testing before switching to the ABS 2000 and found that the ABS 2000 was more sensitive in picking up antibodies, especially anti-E. He mentions that they initially used a 4-cell screen with their ABS 2000's, but this gave them many non-specific antibody reactions that caused several unnecessary workups. Consequently, the laboratory has switched from using a 4-cell screen to a 2-cell screen, which was followed by a significant decrease in the number of 'unnecessary' work-ups.
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