Changes in Peripheral Blood

With age, average values of hemoglobin and hematocrit decrease slightly but remain within the normal adult range. Mean corpuscular volume increases slightly, but RBC morphologic characteristics do not change significantly. RBC content of 2,3-diphosphoglycerate decreases, and RBC osmotic fragility increases. ESR increases significantly. Levels of fibrinogen and coagulation factors V, VII, and IX increase.

RBC life span, total blood volume, RBC volume, and platelet morphologic characteristics do not change with age. Platelet counts have been reported as either normal or slightly decreased, and platelet function has been reported as normal, decreased, or increased.