Blood donation
A blood donors donates approximately 500 ml of his/her blood directly into a sterile bag system. The blood bag is then centrifuged, and the cell components get separated from the blood plasma. What remains is a bag of erythrocytes and a bag of so-called recovered plasma. In some blood banks the platelets i.e. the buffy coat are collected as well.
Erythrocytes are imminently needed in hospital for surgeries and critical care.
Some specific blood is also necessary for the diagnostic industry.
What is ...
Blood is a body fluid in that delivers necessary substances such as nutrients and oxygen to the cells. Blood is composed of blood cells suspended in blood plasma.
The blood cells are mainly red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). The most abundant cells are red blood cells.
The human body has in average approximately 5 liters of blood.
Every transfusion must be cross-matched in order to see if the receipients blood and the erythrocyte bag selected for the patient are fully compatible.
Diagnostic companies manufacture special test kit for these kinds of test.
This means a blood donation for a diagnostic purpose safes life as much as a blood donation for a human transfusion.
There is no alternative for blood yet, but there are possibility to mitigate the blood loss in planned surgeries. For over a decade transfusional systems worldwide work on the so-called patient blood management in order to minimize the transfusion of erythrocytes.