Glycated Hb was measured and compared between five healthy donors (AA), seven non-diabetic and non-transfused homozygous SCD patients (SS) and five non-diabetic, transfused SS patients. The single cell glycation was assessed by flow cytometry using mouse anti-human HbA1c antibody. The inventors demonstrated that glycated Hb was significantly lower in SS patients than in healthy donors (glycated HbS =3.7%, glycated HbA =5.3%, p=0.0025 by DCA and HPLC respectively, and by flow cytometry p=0.0061). In transfused SS patients, results showed that glycated Hb was lower in autologous SS-RBCs than in AA-RBCs by a factor of four (P= 0.008), thus confirming the characterized reduced lifespan of SS RBCs. Glycated Hb levels were measured in RBC sub-populations based on their HbF level (high HbF or low HbF subfractions) in non-transfused SS patients. Single cell glycated Hb assessed by flow cytometry allows to simultaneously estimate the relative age of different RBC sub-populations. This new tool is noninvasive and requires only one single time point measurement.
The present invention relates to a method for in vitro determination of the relative age evaluation of subpopulation of red blood cells by using intracellular glycated hemoglobin measurement by flow cytometry.