Criteria of maturity and age of red blood cells.

Any work on red blood cells requires information about the characteristics of a cell population. Using buoyant density separation of red blood cells (RBC) in a dextran medium during a bleeding anemia of rabbits cell-physiological, ribosomal, mitochondrial and cytoplasmic criteria were estimated in order to select parameters useful for the characterization of a given RBC population according to its developmental stages. Useful criteria for an unknown overall RBC population are reticulocyte count and aspartate amino transferase, or glucose-6-phosphate dehydrogenase activity or creatine concentration. Useful additional criteria for reticulocytes are the mean cellular volume and the RNA concentration.