Reagent and method for the permeabilization and identification of rthrocytes

A process for the permeabilization of erythrocytes is new and comprises successively subjecting the erythrocytes to: (a) a fixation agent comprising an aliphatic aldehyde and an oligosaccharide; (b) a permeabilization agent comprising a detergent and an oligosaccharide. Independent claims are also included for the following: (1) a kit (I) for the permeabilization of erythrocytes comprising: (a) an isotonic or hypertonic fixation agent comprising an aliphatic aldehyde and an oligosaccharide; (b) a permeabilization agent comprising a detergent and an oligosaccharide; (2) a kit for immunolabeling fetal erythrocytes comprising a permeabilization kit (I) and two antibodies against two fetal antigens that are independently expressed on the erythrocyte; and (3) a process for identifying fetal erythrocytes by immunolabeling, comprising successively subjecting erythrocytes to: (i) a fixation agent comprising an aliphatic aldehyde and an oligosaccharide in an isotonic or hypertonic medium; (ii) a permeabilization agent comprising a detergent and an oligosaccharide; (iii) a washing agent for eliminating the detergent; and (iv) two antibodies against two fetal antigens that are independently expressed on the erythrocyte followed by the detection of fetal erythrocytes.