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Extended Blood Typing Needed for Improving Transfusion Safety

Gloved hand of a lab worker holding four test tubes of blood.
Credit: Ahmad Ardity / Pixabay
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Finding a donor blood match can be difficult for rare blood types. While scientists have called for universal red blood cell genotyping, extended blood matching has been historically expensive and time-consuming. High-throughput DNA-based genotyping can offer a cost-effective way to screen extended blood types, and it could drastically reduce the manual, multi-step process of testing blood groups.


Blood typing is an important medical service that is used to ensure that patients who are given a transfusion are matched accurately with their blood type. Today, patients are routinely tested for ABO blood type to determine if their blood is one of four main types – A, B, AB or O – and either RhD positive or negative, and most patients can be accurately matched with one of these common blood types. But because of advances in medical science, we now can recognize at least 43 different blood group systems, and it’s important, especially for high-risk patients, that blood typing provides a more precise match.1


Transfusion complications for the most vulnerable populations


Most patients who undergo major surgery are given blood transfusions during the procedure, but patients with diseases like sickle cell disease or cancer often require routine blood transfusions to improve their quality of life while fighting the disease. When a patient receives a transfusion that doesn’t precisely match their blood type, it can increase the risk of rejecting a future transfusion or related complications. Patients who need weekly or daily transfusions are at a higher risk of future reactions to the transfusions, so it’s imperative that their care teams find them compatible units of blood.


For those with rare blood types, finding a donor blood match can be extremely difficult. When a patient needs a rare blood transfusion, and the hospital doesn’t have a match in its in-house blood bank, a call goes out to their blood supplier. Sometimes, blood suppliers need to screen hundreds of donors to find a compatible unit, or they may turn to programs such as The American Rare Donor Program and the International Rare Blood Panel to fulfill the need.2


The current state of extended blood matching


Historically, extended blood matching for blood groups beyond ABO was expensive and time-consuming. Testing for extended blood types requires multiple serological tests, traditionally considered the gold standard for blood typing. While some have turned to genetic sequencing for advanced blood typing, it is largely cost-prohibitive for many blood testing services to deploy at scale.


For years, research has shown that DNA-based blood typing enables more accurate selection of blood units for at-risk patients,3 and scientists have called for universal red blood cell genotyping for patients and donors and a national database to enable this precise blood matching.4

Today, the onus is often put on the patients. For sickle cell patients, the US Centers for Disease Control and Prevention advises them to ask for an extended red blood cell antigen profile and share the results with their healthcare provider before a transfusion to reduce the risk of adverse effects.5 However, once the patient’s precise blood type is identified, it can still be a challenge to find a suitable blood match.


Many blood services use race to help guide blood matches, as higher rates of certain rare blood types are typically found in specific populations. This approach leaves room for error, and there’s a need for more precise blood typing.

Some blood services have programs to test donations for rare blood groups so that they can identify the donors and encourage them to come back for future donations, like in 2021 when the American Red Cross launched an initiative to reach more Black blood donors to help patients managing sickle cell disease.6 Between the challenges with testing to finding the right unit of blood to match, healthcare providers are often searching for a needle in a haystack for their most at-risk patients.


Innovations powering access to extended blood typing


For blood services to be able to effectively expand testing for more precise blood matching, they need a scalable solution to analyze more blood groups without the need for multiple tests. That’s why groups such as The Blood transfusion Genomics Consortium (BGC) are working to find and validate new molecular genomics solutions to provide a scalable solution for blood centers around the world to perform extended blood typing. According to BGC, “a comprehensive and affordable extended antigen-typing assay is needed, to test large numbers of donors and patients.”7


As an international partnership between blood services, research institutions and industry leaders, BGC aims to improve the safety and efficiency of blood transfusions by introducing cutting-edge genomics technology into clinical practice.8 The group’s initial research shows strong concordance between molecular genotyping and traditional blood typing methods, concluding that genotyping “greatly simplifies the challenge of finding compatible blood for complex patients.”9


High-throughput DNA-based genotyping can offer a cost-effective way to screen extended blood types, and it could drastically reduce the manual, multi-step process of testing blood groups at different labs and on multiple machines. Not only could this help improve blood matching between patients and donors, but it can also make transfusions safer, simplify blood type reporting, and help blood services groups increase rare blood donations. 


About the author:

Deepali Mohindra, MBA, is a seasoned professional in the life sciences industry, with expertise leveraging technology to address challenges in genomics and personalized medicine. She currently serves as the senior manager of global market development for microarrays at Thermo Fisher Scientific, specializing in human genotyping. Previously, she was part of Dionex Corporation, a leader in ion chromatography, which was later acquired by Thermo Fisher Scientific.