Codocytes and Target Cells

Abstract

Codocytes are bell-shaped erythrocytes. The “bells” are always thin-walled and shou Id not be mistaken for th ick-walled cups or stomatocytes. The mean corpuscular hemoglobin volume and mean corpuscu lar hemog lobi n concentration of codocytes are always low. Codocytes can be thought of as cells whose envelope is too large for their hemoglobin content. Accordingly, their resistance to hypotonic saline is increased, lysis resuIting onIy when the cell membrane is maximally stretched. Codocytes might be considered the antithesis of spherocytes, which have too little membrane for their volume and hence increased susceptibiIity to lysis or increased “osmotic fragiIity.”