Small, densely-staining cells with several irregular projections.

Blister: Cell has vacuole on one side. Caused by removal of inclusions.

Bite: Cell is indented, like someone has taken a bite out of it. Caused by removal of inclusions or bursting of blister cell.

Seen in G-6-PD deficiency and hemoglobinopathies.

Cell has evenly distributed “bumps” along surface. Central pallor is still visible.

Can be artifactual due to slide preparation. Suspect when found in large numbers or only in certain areas of the slide.

Ovalocytes are typically more egg shaped while elliptocytes are skinnier and more pencil shaped. Terms are often used interchangeably.

Thin, crescent-shaped cell with pointed ends, usually lacking central pallor.

Seen in patients with Hgb S (sickle cell)

Small, spherical RBCs that stain densely and lack central pallor.

May appear as artifact in thinner area of the slide where RBCs have cobblestone effect.

Cell looks like target or bullseye. Ring around central area of hemoglobin should be fairly clear. If it looks “blurry,” the target cell may be artifactual due to slow slide drying or excess EDTA.

Teardrop or pear-shaped cell. Tail should be blunt; Sharp projections all going in the same direction are artifactual from slide-making.

Fragmented cells with several different subcategories such as helmet cells (AKA bite cells). Cell lacks central pallor.

Cell has central slit, making it look like a mouth. If slits are all oriented in the same direction, it is likely artifactual from slow slide drying.

RBCs clump together which can hide other RBC morphology.

RBC stains diffusely blue/gray due to residual RNA.

Slightly larger than mature RBC.

RBCs stack together like coins in a linear fashion. Can be seen normally in thicker areas of the slide.

Excess proteins in blood may also cause the slide to stain more blue.