Elimination of leucocyte artefacts from erythrocyte filtration tests

Abstract

The Imugard IGSOO cotton wool pre-filtration technique, used to remove leucocytes from whole blood prior to study of erythrocyte deformability, has been tested to determine whether it selectively retains less deformable erythrocytes. Leucocyte-free suspensions of erythrocytes prepared in parallel by this technique and by centrifugation in narrow-bore Wintrobe macrohaematocrit tubes gave similar values for filtration through 5 µm pores in the Hemorheometre. Erythrocytes that passed through Imugard IG SOO cotton wool gave similar density profiles to whole blood when fractionated on a Percoll-Stractan continuous density gradient. Erythrocytes retained by, and subsequently eluted from, the cotton wool did not show impaired deformability as measured by the Hemorheometre or Ektacytometer. We have been unable to demonstrate selective retention of less deformable erythrocytes by Imugard IGSOO cotton wool.