In Focus
The impact of molecular testing
How has the implementation of molecular testing in immunohaematology laboratories influenced clinical outcomes and patient care?
Traditionally the testing carried out in the Immunohaematology Laboratory was based on serological methods and an intimate understanding of the antigen-antibody interaction. However, over the past two decades DNA testing has become fully embedded and considered part of the decision-making process in transfusion medicine.
Molecular testing in immunohematology has been firstly implemented in highly specialized laboratories about two decades ago. Whilst there are some recognised limitations of DNA analysis for predicting blood groups, the benefits outweigh the perceived limitations in most circumstances. Here we explore how the implementation of molecular testing in immunohaematology laboratories has influenced clinical outcomes and patient care.
Enhanced Blood Typing Accuracy
- Precision: Molecular methods provide precise determination of blood group genotypes beyond what traditional serological methods can offer, identifying rare or weak antigens.
- Personalisation: They allow for improved matching of blood donors and recipients, reducing the risk of alloimmunisation, especially in patients requiring chronic transfusions.
Improved Management of Hemolytic Disease of the Fetus and Newborn
Fetal/neonatal alloimmune disorders: Molecular tests can detect feto-maternal incompatibilities early, aiding in the management of conditions like hemolytic disease of the fetus and newborn (HDFN).
Targeted Antibody Identification
Complex cases: Molecular testing helps in identifying antibodies that might be missed or misidentified by serology, particularly in recently transfused patients with multiple or weak antibodies.
Genotype-Based Compatibility
- Genotype match: Molecular tests allow for genotype matching of donor and recipient for non-ABO antigens, and can improve transfusion compatibility and reduce complications.
- Prevention of alloimmunisation: Molecular tests can help in identifying the potential alloantibodies that a patient may develop and that could cause transfusion reactions, and enabling preventative patient management. This is especially beneficial for patients who receive frequent transfusions, such as those with sickle cell disease or thalassemia.
Stock management
Inventory management: Molecular tests can improve inventory management of blood products, ensuring that rare types are available when needed.
Prevention of Adverse Transfusion Reactions
- Safety: By providing more fully typed donors, molecular testing can reduce the risk of adverse transfusion reactions through more extensive matching, enhancing patient safety.
- Improved outcomes: Better matching and early identification of potential issues can lead to improved transfusion outcomes and overall better patient care.
Application in Rare and Complex Cases
- Rare blood types: Molecular testing facilitates the identification and management of rare blood types in both patients and donors, that might not be possible with traditional serological methods.
- Genetic variations: Molecular methods can detect genetic variations responsible for variant or weak blood group antigens.
Challenges and future directions
- The initial setup and ongoing costs of molecular testing, including equipment, reagents, and skilled personnel, can be prohibitive for many laboratories.
- Reimbursement issues: Insurance reimbursement for genotyping tests may not be straightforward, leading to financial challenges for laboratories and patients.
- Workforce regarding expertise in the field of blood group genetics is still challenging and due to the wider implementation of genomics in many other areas of medicine.
- Artificial intelligence (AI) assisted reporting interpretation tools could generate detailed reports with the interpretation of complex genotyping data, making it more accessible to laboratory staff without specialised training in blood group genetics.
