There is tremendous demand for blood in hospitals. Many patients suffer because they are not able to cope with the loss of blood.
There is tremendous demand for blood in hospitals. Many patients suffer because they are not able to cope with the loss of blood. Blood that is donated is basically used to:
Thus, blood donation is of prime importance, as it can help save the life of a patient.
|Type of Vaccine||The period in which donation should beavoided|
|Hepatitis B||6 months|
|Live vaccines||2 weeks|
|Killed vaccines||48 Hours|
At the time of donation, only 350 ml of blood is taken. An average person has 5-6 litres of blood in the body. In terms of volume the loss is corrected in 24-48 hours by the body. The red cell count is corrected in about 56 days.
The actual bleeding time is about 5-6 minutes. There will be a medical check up before this and the donor is advised some rest (for 5-10 minutes) and given some refreshment after donation. The whole process takes about 30 minutes.
The minimum time advised between two donations is 3 months. This gap helps blood regain the normal haemoglobin count.
The health of the donor will not suffer because of the blood donated. In fact, the bone marrow is stimulated to produce new cells. However if conditions are not hygienic, the donor may be exposed to infection.
It is important to be sure that disposable needles are used for bleeding. An important precaution is from Human Immunodeficiency Virus (HIV), the virus that causes AIDS. The virus can be transmitted through blood transfusion, so all donor programs are required to question donors about possible HIV exposure, and to test donated blood for this virus.
There is a rare form of HIV called Type O that is found in western Africa. The available tests for HIV do not always detect the Type O strain. This means that blood programs must take special precautions to keep this virus out of the blood supply by not taking blood donations from those who have been where the virus is found.
It is possible that the tests used to screen donated blood may someday be improved so that they detect Type O HIV. When that happens, restriction on donations may be removed.
The blood that is donated is screened for the following diseases/infections:
The blood is grouped and stored either as whole blood or as components like Packed red blood cells, plasma or platelets. This is then sent on demand to hospitals.
Blood is composed of cells suspended in a liquid. The liquid
portion is the plasma, from which therapeutic fractions and
derivatives are made.
Suspended in the plasma are three types of cells:
Red cells: These carry Oxygen
White cells: These fight infection
Platelets: These stop wounds bleeding
The most common type of grouping is the ABO grouping. Red Blood Cells have a protein coat on their surface whichdistinguishes them. According to this blood is divided into four groups:
• A (A protein is present),
• B (B protein is present),
• AB (AB protein is present),and
• (No protein is present).
There are subtypes under this grouping (listed as A1, A2, A1B or A2B…), some of which are quite rare. Apart from this there is another protein which plays an important part in the grouping of blood. This is called the Rh factor. If this is present, the particular blood type is called positive. If it is absent, it is called negative. Thus we have the following broad categories:
• A1 Negative
• A1 Positive
• A1B Negative
• A1B Positive
• A2 Negative
• A2 Positive
• A2B Negative
• A2B Positive
• B Negative
• B Positive
• O Negative
• O Positive