acanthocyte

thumb|Acanthocytes, from peripheral blood, under light microscopy. Note the irregularly shaped, non-circular cells in the image.

Acanthocyte (from the Greek word ἄκανθα acantha, meaning 'thorn'), in biology and medicine, refers to an abnormal form of red blood cell that has a spiked cell membrane, due to thorny projections. A similar term is spur cells. Often they may be confused with echinocytes or schistocytes.