The presence of hemolysis is characterized by pink to red plasma of varying intensity readily observed during sample centrifugation in a microhematocrit tube. Hemolysis can occur in vivo or in vitro; when it occurs in vivo, this phenomenon is generally accompanied by hemoglobinuria and linked to hemolytic anemia. Note the normal yellowish plasma in the tube placed on the right; it comes from a healthy animal and has not undergone hemolysis. Compare this tube to that placed to the left that comes from an animal suffering from immune-mediated hemolytic anemia with important intravascular hemolysis.