The use of intracellular dyes to create a multiplexed flow cytometry-based red blood cell phenotyping assay.

ABSTRACT

BACKGROUND AND OBJECTIVES: Flow cytometry can be used to phenotype red blood cell antigens, allowing for high-throughput testing while using low reagent volumes. This article utilizes intracellular dyes to pre-label red blood cells to further multiplex flow cytometry-based red blood cell antigen phenotyping. MATERIALS AND METHODS: Red blood cells were pre-labelled using the intracellular dyes V450 and Oregon Green. These dyes are detected fluorescently via flow cytometry. Four combinations of intracellular staining were used to allow four patient or donor red blood cells to be analysed in a single test well. Antigen phenotyping was then performed via flow cytometry using a previously described method. RESULTS: The intracellular dyes showed uniform staining when measured in mean fluorescence intensity and allowed the red blood cells to be clearly distinguished from one another. The presence or absence of red blood cell antigens was determined with 100% accuracy. CONCLUSION: The use of intracellular dyes allowed a fourfold increase in the throughput of our previously described flow cytometry-based red blood cell antigen phenotyping method. The described method allows up to 48 patients to be simultaneously phenotyped using a single 96-well microplate. Furthermore, additional fluorescent dyes could potentially increase the throughput exponentially.