The stages of osmotic haemolysis.

Abstract

The haemolysis of individual human erythrocytes has been observed using an inverted microscope and cine‐camera. 2. With each permeant (glycerol, propylene glycol, ethylene glycol, urea and water) haemolysis is a multistage process. The stages are swelling, popping, reduction in volume possibly accompanied by ion leakage and, finally, haemoglobin leakage. 3. The classical haemolysis time (Th) is made up of a swelling time (Tsw) and a stress time (Tst). Tst is not negligible and with the faster permeants it may occupy more than 75% of the haemolysis time. 4. The stress time can also be divided into two parts: a K+ leak time (TK) during which the cell shrinks and a time (THb) during which haemoglobin is leaving the cell. THb occupies a substantial part of Th, from 25 to 65%, and is relatively longer in fast haemolysis. 5. There is a wide spread in the permeability coefficient to glycerol in a population of erythrocytes. The distribution is compatible with a Gaussian distribution. The mean permeability is 1‐79 X 10(‐6) cm/sec and the S.D. is +/0 0‐45 X 10(‐6) cm/sec. 6. The correlation between haemolysis time and swelling time for individual erythrocytes is poor, especially for fast haemolysis. Consequently, a measure of the distribution of haemolysis time does not give a related distribution of the swelling time or of the calculated permeability for individual erythrocytes. © 1975 The Physiological Society