Improved method for the concentration and purification of faecal cysts of Entamoeba histolytica for use as antigen.

Human stool samples are the most widely used source of E. histolytica cysts for diagnosis and research. Cysts concentrated from faecal samples are contaminated with faecal debris and bacteria and are unsuitable for use as antigens. Other gradient purification and sedimentation procedures result in considerable cyst losses. We present an effective and simple purification procedure using varying densities of Percoll that yields an adequate cyst concentration from a moderate cyst load in a single stool sample.