Application of the Inverness Blood Grouping System for semiautomated ABO and D testing of patients’ samples

We evaluated the performance of the Inverness Blood Grouping System (IBG Systems, Inc., Laytonsville, MD) for the ABO and D red cell grouping of patients’ samples. The IBG System is a semiautomated microplate device for blood grouping and antibody detection. We tested 2,051 samples using the IBG System and by manual grouping techniques. In no instance did the IBG System give a final ABO interpretation different from the final manual technique. For three samples, the IBG System’s ABO interpretation was different from the manual interpretation. An error in interpretation by the technologist performing the manual testing was responsible for the discrepancies. The IBG System identified one sample as D-positive that was grouped as D-negative by manual testing. The patient’s sample had been previously grouped manually as a weak D. All other D results were in agreement. The IBG System provided ABO interpretations without technologist’s intervention on 1,765 (86.1%) of the samples. In 153 (7.5%) of the samples, a single, equivocal reaction required visual inspection, but no repeat testing was necessary. In 133 (6.5%) of the samples, either repeat testing or reliance on only the manual results was required for final ABO group interpretation. The IBG System is a reliable and efficient alternative to manual techniques for ABO and D grouping of patients’ samples.