Roughly half a human body is red blood cells.

Roughly half a human body is red blood cells.

Approximately 84% of the cells in the human body are 20–30 trillion red blood cells. Nearly half of the blood's volume (40% to 45%) is red blood cells. Packed red blood cells (pRBC) are red blood cells that have been donated, processed, and stored in a blood bank for blood transfusion.

Function: Oxygen transport

Acronym(s): RBC

Red blood cells make up about 45 percent of the blood (the remainder is 55% plasma and less than 1% consists of other cells: thrombocytes and leukocytes).

Red blood cells carry oxygen from your lungs to your tissues. They also bring carbon dioxide back to your lungs. Red blood cells make up almost half of your blood. The lifespan of a red blood cell is around 120 days.