Almost all animal species—including humans—have blood cells, but between different species our blood tells different stories. The lineage and components of blood cells vary widely, and this variety is ...

Blood cells carry a deep evolutionary history. A new analysis suggests their earliest ancestors were macrophage-like cells inherited from single-celled life.

Platelets are small types of blood cells that prevent excessive bleeding. It’s possible to develop low or high platelet counts related to a number of health conditions. Platelets are one of the main ...

Every second of every day, the human body replaces roughly two million red blood cells that have reached the end of their ...

There are different blood types: A, B, AB, and O, with each also being Rh-positive or Rh-negative. Knowing your blood type is ...