Model of elevated hematocrit in mice. RBCs from “donor” mice were injected into “recipient” mice (RBC^HIGH) via retroorbital plexus. After 24 hours, blood was drawn from RBC^HIGH and control (uninfused) mice. Complete cell counts indicate (A) elevated hematocrit, but normal (B) neutrophil, (C) monocyte, and (D) platelet numbers. In panels A-D, each dot is a separate mouse; lines indicate median values, and boxes represent the normal range. (E) Blood smears (Diff-stain kit [IMEB, San Marcos, CA], imaged on an Olympus BX71 at ×40 and digitally zoomed) of washed RBCs and whole blood from control and RBC^HIGH mice indicate normal RBC morphology. (F) Flow cytometry indicates normal phosphatidylserine exposure on washed RBCs and RBCs isolated from control and RBC^HIGH mice. Bars indicate mean ± SD, N = 3. (G) Viscosity measurements show RBC^HIGH mice (closed circles) have significantly increased viscosity (Pascal-seconds, Pa.s) at low and high shear compared with control mice (open circles). Symbols show mean ± SD, N = 3-5 per group.