USEFUL KNOWLEDGE ON MOLECULAR GENETIC BLOOD GROUP TYPING
Advantages of the molecular genetic blood group typing?
With the "Guideline for the Collection of Blood and Blood Components and the Use of Blood Products (Guideline Haemotherapy)", revised in 2017, the German Medical Association has set further quality standards for donors and recipients of blood products. Since this time at the latest, molecular genetic methods for blood group typing have found their way into routine patient diagnostics and represent an important supplement to serological diagnostics [1.].
The selection of suitable blood components in transfusion and transplantation is still based on the serological blood group identification of the Viennese pathologist Karl Landsteiner from more than 100 years ago.
For special questions, molecular genetic methods have already been used for many years for blood group diagnostics. The aim of this overview is to present the molecular biological background and the possibilities of using molecular genetic blood group tests.
We have compiled for you the concrete advantages that result from this.
What are the advantages of molecular blood group typing for your laboratory?
Here are the most important potential applications at a glance:
In case of weak or unclear serological results
More safety in transfusions through the molecular genetic second line determination. With this supplement, many questionable diagnostic results can be clarified.
For the initial determination and / or if you want to be independent of rare and expensive blood group reserves.
For some blood group systems, it is possible to perform the initial typing directly on a molecular genetic basis, for example for the rare blood group systems.
The test sera of rare blood group alleles are often difficult to obtain or very expensive. Due to the distribution, very few people carry these blood group alleles, which makes the production or procurement of the starting material complicated or it is simply not available.
If the aim is to use precious rhesus D negative blood sparingly.
The determination of the Weak D types can be helpful in this context. Weak D types 1, 2 and 3 are the most common of the Weak D types and patients with these Weak D types can receive RhD positive blood. All other Weak/Partial D types must receive rhesus D negative blood.
Rhesus prophylaxis - Yes or No
Through targeted typing of mother and father (determination of RhD zygosity), the decision can be made as to whether Rhesus prophylaxis is necessary or whether it can be dispensed with.
For HNA and HPA typing
Very helpful for:
- clarification of suspected TRALI (transfusion-associated acute lung insufficiency),
- clarification of suspected NIN (neonatal immune neutrophenia) and NITP (neonatal immune thrombocytopenia). These are diseases of comparable pathogenesis to Morbus Haemolyticus Neonatorum (MHN). Immune reactions against neutrophil granulocytes or platelets of the child can also occur in the HPA and HNA systems during pregnancy,
- in preparation for granulocyte and platelet transfusions, especially if antibodies against HNA or HPA are already known
To reduce alloimmunisation and haemolytic transfusion reactions.
If both patients and donors are comprehensively typed, the risk of alloimmunisations and thus of haemolytic transfusion reactions is reduced. If even the rare blood group systems are tested and also matched, compatibility is better and alloimmunisations are no longer accepted. The risk of haemolytic transfusion reactions is reduced as well.
For patients who have received several transfusions already or haematological/oncological patients.
For patients with acquired antibodies, especially if these antibodies are directed against common blood group characteristics, it is often difficult to find suitable donors.
Unclear serological results.
Serology reaches its limits in multiple transfused patients or patients with autoimmune haemolytic diseases (AIHA), alloimmune antibodies, hemolytic disease of the newborn (HND) or after bone marrow transplantation. These results are often inconclusive. Molecular genetics provides clear and unambiguous results in these cases.
For patients with
- already acquired antibodies (AB)
- in the presence of multiple antibodies
- in the presence of antibodies against frequently occurring rare blood group characteristics
Here it is often difficult to find suitable preserves.
Your experts in blood group typing
Serological or molecular genetic blood group typing - both methods have their scope of application.
Do you have any questions about the methods, our matching test kits or about blood group typing in general? I will be happy to help you with advice and practical support. Send me an e-mail or contact me by phone.
Bibliography and recommended reading
1 Mullis, K. B. (1990): The unusual origin of the polymerase chain reaction. In: Scientific American 262 (4), 56-61, 64-5. DOI: 10.1038/scientificamerican0490-56.
2 Maheaswari, Rajendran; Kshirsagar, Jaishree Tukaram; Lavanya, Nallasivam (2016): Polymerase chain reaction: A molecular diagnostic tool in periodontology. In: Journal of Indian Society of Periodontology 20 (2), S. 128–135. DOI: 10.4103/0972-124X.176391.
3 Applied Biosystems®, life technologies™: Real-time PCR handbook. Basics of real-time PCR. In:. Online https://www.thermofisher.com/, zuletzt geprüft am 13.05.2020.
4 Joshi, Mohini; Deshpande, J. D. (2011): POLYMERASE CHAIN REACTION: METHODS, PRINCIPLES AND APPLICATION. In: Int Jour of Biomed Res 2 (1). DOI: 10.7439/ijbr.v2i1.83.
5 Calculations for Molecular Biology and Biotechnology (2016): Elsevier.
6 Deepak, S. A.; Kottapalli, K. R.; Rakwal, R.; Oros, G.; Rangappa, K. S.; Iwahashi, H. et al. (2007): Real-Time PCR: Revolutionizing Detection and Expression Analysis of Genes. In: Current Genomics 8 (4), S. 234–251.
7 Holzapfel, Bianca; Wickert, Lucia (2007): Die quantitative Real-Time-PCR (qRT-PCR). Methoden und Anwendungsgebiete. In: Biol. Unserer Zeit 37 (2), S. 120–126. DOI: 10.1002/biuz.200610332.
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