Last updated:09-05-2008
Bookmark and Share


Blood is defined as a blodoverførsel from a man (donor) to another person (receiving).

When they have different diseases like. malignant blood disorders or liver disease, can be seen low blood, and there is a need to provide extra blood to the body. Blodmanglen can also be caused bleeding, for example. seen in the context of a bleeding ulcer, operations or in traffic accidents.


In Denmark collected annually around. 370,000 unit of blood, and each blood unit consists of one-half litres. A blood collection is in a vein, is not painful, goods around. 20 min. and involve no risk of becoming infected with HIV. Just after a blood donor can be a good feel a little dizzy, but it is quickly after that, for example. drinking a soda. In a few days, the bone marrow formed new blood again. Most people do not have some genes after a blood donation, and unless you

Before becoming a donor, blodbanken ensure that there is no risk to the donor is infected with various viruses, such as. HIV Or various forms of hepatitis . This is done by the donor to question whether there are some facts that could increase the risk of being infected, for example. former drug abuse, travelling in tropelande, former diseases, unprotected sex, etc. There will be a blood test on the donor, which examined the various viruses. If this does not show signs of virussmitte, accepted the donor, but also screen the donated blood each time to guard against infection.

However, there is still a minimal risk of infection by blood transfusion. In Denmark, which 1 person infected with HIV each. 2 million transfusions and 1 per person with hepatitis. 200,000 transfusions. We should always consider the complications that may arise and the risk of death, if we do not receive a blood transfusion.

A blood donation may be given to blodbanken because we want to help other people who are in danger or serious diseases. If you have to undergo an operation in the near future, you can donate blood to blodbanken, which will keep it in cold storage, then you can have it sprayed into his own blodbane during the operation, if this should be necessary.

Blodets components

The blood consists of:

  • Red cells (the red blood cells). Priority will be given transfusion of red cells in cases of anaemia ( anaemia).

  • Platelets (platelets). In the case of, for example. thrombocytopenia Where there is a bleed, a portion of concentrated platelets.

  • The white blood cells filtered out and are not used for transfusion.

  • Plasma (amber liquid), which contains nutrients, coagulation factors (størkningsproteiner), salts and antibodies. By example. liver disease can be lacking coagulation factors, which may give bleeding And this will transfusion of one unit of plasma reduce the bleeding.

When blodbanken receive a blood donation, separating the main blood to ensure an efficient use of the blood. This will enable more patients to benefit from a donation, and to ensure a high quality, as the other blood components are removed. The components will be stored at different temperatures.


When you give a unit of blood, it is important that the blood has the same blood type as the recipient, otherwise life-threatening complications can occur. So take a blood sample to examine blodtypen in a blood transfusion. There are various methods to determine blodtypen where AB0-type and Rhesustype here be discussed.

By AB0 system looks on some characteristic substances (antigens) on the surface of the red blood cells, A and B, and their corresponding antibodies in the blood plasma, anti-A and anti-B. These overflademarkører can be seen in the following combinations: A = blood types A, B = blood type B, both A and B = blood type AB, either A or B blood type = 0 (zero). Equally matched the blood of antibodies in the plasma: Blood type A has anti-B blood type B have anti-A, blood group AB has no antibodies and blood

Rhesus system is a complex system that is used to classify blodtypen. Here are Rhesus D antigen a significant role, and have this antigen, is Rhesus positive, and the lack of it, is Rhesus negative. Blodtypesystemerne is genetically determined (see genetics) And there are other systems that are not mentioned here.

A BAS (blood antibody-screentest) test is taken before a blood transfusion. This is done to ensure that there is formed irregular antibodies to the above blodtypesystemer. BAS test applies in 5 days, and it is valid, must be given blood in this period.

Is it not time to determine blood type and make a BAS-test by suddenly arose the need for blood transfusion, you can always give blood 0 Rhesus negative, because of the lack of antigen in the blood.


If you give a blood transfusion, which does not match the recipient's blood, antibodies can sit down on the antigens on the surface of the red blood cells. This may start a response from the immune system, resulting in the red blood cells are broken down, which may give hemolytic anemia .

The response from the immune system can run riot and result in a anaphylactic shock . There may also be developed renal failure .

In addition, it must be pointed out Rhesusgrupperne during pregnancy, where the mother is Rhesusnegativ and father Rhesuspositiv (see Rhesus-reaction of the fetus .

Infections with the virus, see the definition above.

Prevention of complications of blood transfusion

By ensuring the correct identity under blodprøvetagning and blood, while making the necessary screening test for blood type and antibodies, reduces the risk of complications significantly.




Related articles:

Blodets constituents
Viral infection and Bacteria in the blood (Sepsis and Bakteriæmi)



Top 5


Information on these pages should not replace professional doctors.
© Copyright 2010 Health & Disease - All rights reserved
Search health and
You are here: