Potassium efflux: a simple method to determine intactness of erythrocytes

This article describes a simpler approach to checking the integrity of erythrocyte membrane and internal milieu of the human erythrocyte. Potassium (K+) and hemoglobin (Hb) effluxes were studied in erythrocytes incubated with buffer G (pH 7.4) at varying time intervals and temperatures. Potassium in the supernatant was measured by direct ion selective electrode method and Hb by cell counter following incubation for 0 to 3 hours at 4 degrees to 55 degrees C. Basal adenosine triphosphate levels were also determined during varying time intervals at 37 degrees, 50 degrees, and 55 degrees C. At 4 degrees, 25 degrees, and 37 degrees C, insignificant (P greater than .05) amounts of K+ and Hb were released; amounts were significantly higher (P less than .0005) after 2 hours of incubation at 45 degrees for K+ and 50 degrees C for Hb. After 30 minutes at 55 degrees C, maximum K+ and Hb concentrations were found in the supernatant; concentrations remained the same up to 3 hours. Basal levels of adenosine triphosphate in the erythrocytes decreased significantly with time at higher temperatures. We conclude that K+ efflux, being more sensitive than Hb and more erythrocyte concentration-dependent, can be used as an effective method to confirm the intactness or viability of red blood cells.