Evaluation and calibration of a fluorescence-activated cell sorter for the interpretation of the granulocyte immunofluorescence test (GIFT)

Publisher Website
Google Scholar
Abstract
The increasing availability of fluorescence-activated cell sorters (FACS) and flow cytometers makes it reasonable to consider the routine use of these machines for the evaluation of the granulocyte immunofluorescence test (GIFT). A comparison of microscopic reading and FACS reading of the standard GIFT demonstrated equivalent simplicity, specificity, sensitivity, reproducibility and duration of test procedure. Differentiation of a negative GIFT from a weakly positive GIFT using the FACS reading method was, however, made difficult by considerable variation in background fluorescence for different neutrophil donors. However, we demonstrate that the FACS reading method was superior for the interpretation of immunofluorescence on chloroquine-treated neutrophils used in the differentiation of HLA from neutrophil-specific antibodies. The systematic study highlighted the fact that any laboratory contemplating conversion from microscopic reading of the GIFT should carefully evaluate and standardize their interpretation of FACS results with their manual reference method.