This schematic depicts a well-made peripheral blood smear. A drop of blood has been placed on the left-hand side of a clean glass slide at point A, and has been pulled towards the right-hand side using another glass slide, stopping at point B. The area near point A is too thick and too darkly stained for interpretation, whereas the area at the very end of the smear, near point B (the "feather edge") is too thin, distorting the morphology of all cells in that area. The optimal area for viewing is just behind point B (shown by the asterisk), in an area where the red blood cells are just touching and demonstrate central pallor.
