First, anyone who has heard of "transfusion medicine" and wants to know what it is. And then to all medical professionals and also interested non-medical professionals who want to know more about it. Almost all my texts are proofread by my husband. He has nothing to do with medicine, but he has always shown a genuine interest in how things work and why medical professionals do things one way and not another. After more than ten years of marriage, he already has a solid basic vocabulary knowledge. Therefore, a complete layperson may need help understanding the texts - but there is a glossary. And, of course, Google MD 😊.

On the other hand, colleagues in the field might find everything too simplified. But once someone has taken the "bait", they have countless opportunities to explore the matter further.

As a medical doctor trained in the "old school" curriculum, I had no knowledge of transfusion medicine. This subject was not emphasized during my studies, and as a freshly graduated MD, I was unaware that specialist training in this area was available. It was only during my residency in a clinical subject that I realized transfusion medicine was a separate area of specialization. As a result, it is challenging to recruit junior doctors in this field. However, at Innsbruck University Hospital, elective courses in transfusion medicine are available during the KPJ program.

Initially, I knew only that there were four blood groups, and that transfusing them indiscriminately could result in the patient's death. However I was completely unaware of how this knowledge could be used to build an entire discipline. 

So I started researching and was in for a big surprise.

The four blood groups A, B, O and AB - even though they are the most important, they get lost in the mass of the other 300-400 blood groups. It is challenging to give a precise number because new BGs are discovered constantly.

Additionally, antibodies can form against each blood group after a transfusion or pregnancy, making it even more complex.

And that's where it gets exciting.

Suppose a patient needs blood. The blood group is determined, and screening is carried out for these irregular antibodies (this is always an obligatory part of a BG determination). And yes, he has them - not one or two, but three. The challenge now is to determine the specificities of the AK - that is appropriately called antibody identification or antibody differentiation, and it can be an extremely time-consuming and tedious job. And once you have identified the antibodies, the search begins for matching units of blood that do not have the antigens the found antibodies are directed against. With three - or more - antibodies, it is sometimes impossible to find such blood units, especially if they are directed against a common antigen. In such cases, one sometimes must cooperate with other blood banks - and not just the Austrian ones. However, the scenario described here is relatively rare in practice. Most patients with an irregular antibody only have one or two, and it is no problem for a large blood bank to find suitable blood units. Provided, of course, that it is not an emergency with a massive transfusion in which 20 to 30 units of blood have to be supplied. But even this case does not happen often (and everyone who works in a blood bank and immunohaematology lab hopes it stays that way 😉 ).

All right, but a whole discipline just FOR THAT?????

No, of course not.

Transfusion physicians are also responsible for producing and supplying all blood products. In addition to red cell concentrates, these include the following products and procedures:

• Platelet concentrates - like blood units, except they contain only platelets instead of red cells
• Plasma
• Stem cells (which are needed for transplantation to treat e.g. leukaemia)
• Granulocyte concentrates and other fraction aphereses (individual components of the blood)
• Red blood cell concentrates are usually prepared from a whole blood donation. However, they can also be produced by red cell apheresis. This may be necessary if the donor cannot tolerate a regular blood donation, in which 500ml of blood is taken, but his blood is urgently needed.
• Recently we started the production of serum eyedrops
• By using cellular apheresis, pure component concentrates can be produced - like platelet concentrates. Plasma can also be obtained by plasmapheresis.
• However, apheresis can also be used therapeutically - this makes it possible to selectively remove individual components: leukocytes in a blast crisis during leukaemia or for plasma exchange in many autoimmune diseases.

Apheresis has a relatively "new" application (compared to blood donation) in treating various malignant cancers that can be treated with bone marrow transplantation. This can be done in two ways: autologous - the patient gets their own stem cells back. This works in the following way: The patient is given chemotherapy, and when most of the cancer cells have been eliminated, they are given a drug - growth hormone for stem cells - G-CSF, which stimulates the release of healthy stem cells from the bone marrow. After about 7-10 days, the patient is ready to have the stem cells harvested by apheresis. This is called an autologous stem cell transplant. However, the transfusion doctors only supply the collected stem cell concentrate. The treatment of the patients is the responsibility of the haematooncologists.

Or it also works as an allogeneic cell donation:

An allogeneic stem cell donation is a donation from an unrelated donor. Whereas in the past, the donor was drilled several times in the pelvic bone under anaesthesia to extract the bone marrow, a stimulation with G-CSF (granulocyte colony-stimulating factor) for about 7 days and 1 - 2 runs of apheresis is sufficient. So if someone is registered in the stem cell registry and they qualify as a donor after all the preliminary examinations, they can choose between stem cell apheresis or bone marrow donation.

And just as cells can be removed from the body, plasma can also be replaced with new plasma or human albumin (protein solution). Autoantibodies are formed in autoimmune diseases and can be directed against anything. Plasma exchange is mainly used in Myasthenia gravis and Guillain-Barré syndrome. In both conditions, the antibodies are directed against an antigen on the nerve fibres and thus lead to muscle weakness. If you want to know more, click on the names - the links lead to excellent descriptions of the diseases (intended for patients without medical knowledge). Conversely, plasma that lacks a particular substance can also be exchanged for donor plasma. This is mainly used for diseases from the group of thrombotic thrombocytopenic microangiopathies.

A significant chapter of transfusion medicine has nothing to do with the discipline at first glance - immunogenetics. Patients waiting for a transplant are analysed (typed) at our clinic for their tissue characteristics. We also follow up on patients after transplantation in terms of antibody rejection. Since Innsbruck is a large transplant centre that serves the west of Austria and South Tyrol, we have a 24-hour on-call service that can immediately type a potential donor from this region. If organs are sent to our patients, a compatibility test between the donor's cells and the recipient's serum must be carried out before the operation, especially in the case of kidney transplantation. But there is much more in immunogenetics (the HLA lab...) 😊.

And last but not least, if there is a transfusion reaction, the cause must be clarified precisely by immunohaematology. Even in the rare case of disease transmission, it must be determined by tracing back the transfusion chain exactly how this could have happened and whether other recipients are not at risk from further blood products. These incidents must be reported to the BASG, which compiles statistics for Austria at the end of the year to see how safe transfusions are in Austria. This is called haemovigilance and is mandatory by law.

A transfusion physician must know how and for which parameters the donated blood products must be tested. He must understand how the individual tests work to assess ambiguous findings and, if necessary, order further tests to confirm or rule out a particular diagnosis.

Supporting gynaecologists in caring for pregnant women with irregular antibodies directed against antigens found on the foetal erythrocytes completes the field of practice.

Last update on 10.08.2023.