Informed consent for blood transfusion should include information that supports the decision to agree or disagree to the transfusion. Adverse reactions, including transfusion-transmitted infections, hemolysis, allergic reactions, fever, and volume overload, are listed in informed consent. Nevertheless, alloantibody formation, platelet refractoriness, and iron overload are not included in the informed consent. Therefore, a consent form that includes these factors should be considered for patients receiving transfusions to support decision-making.

A 91-year-old male patient with chronic obstructive pulmonary disease in the intensive care unit was issued a red blood cell unit. Shortly after issuance, the transfusion failed because of an occlusion in the bedside leukocyte reduction filter. A small clot was observed at the spike portion of the returned filter, but the transfusion failure persisted despite replacement of the filter. On the bedside inspection, a large, irregularly shaped dark clot, approximately 2×2.5 cm in size, was observed within the blood bag, obstructing the filter spike and preventing blood flow. The unit was retrieved and classified as unsuitable for transfusion, and the supplying blood center was notified. A replacement red blood cell unit was then issued. This case highlights the importance of careful visual inspections and prompt management of abnormal blood components to ensure transfusion safety.

Transfusion-associated circulatory overload (TACO) is a largely preventable transfusion reaction through appropriate clinical interventions. TACO is associated with high severity, and numerous fatal cases have been reported. In the UK, analyses of Serious Hazards of Transfusion (SHOT) reports have led to the integration of the National Patient Safety Alert system, strengthening institutional frameworks for TACO prevention from a patient safety perspective. The author presents follow-up actions derived from case analyses in the UK SHOT and proposes measures that can be applied in our setting to prevent TACO and reduce its associated risks.

Thrombocytopenia, a condition involving low platelet counts, is very common in cancer patients. Accordingly, platelet transfusions are performed quite frequently in this population. As a result, studies have been conducted to establish appropriate platelet transfusion practices for these patients, and guidelines have provided recommendations on the thresholds for prophylactic transfusion and appropriate dosing. In real-world clinical practice, however, inappropriate platelet transfusions that deviate from these guidelines remain common. These include transfusions administered despite the platelet counts being above the recommended thresholds, transfusions exceeding the standard recommended dose, and transfusions given to achieve platelet levels required for chemotherapy. Such practices may lead to the inefficient use of limited platelet resources without clear clinical benefit. Therefore, efforts to improve the adherence to established guidelines and optimize platelet utilization are warranted, particularly in cancer patients.

We report the first identification in Korea of the rare ABO*AW31.02-05 allele in a patient with an ABO discrepancy.Forward ABO typing demonstrated a clear B phenotype, whereas reverse typing showed no agglutination. Molecular analysis revealed an ABO*AW31.02-05/B.01 genotype. In silico prediction using PolyPhen-2 and SIFT indicated that both amino acid substitutions (p.Phe216Ile and p.Val277Met) were deleterious, consistent with markedly reduced A-transferase activity. This case highlights the value of genotyping and in silico prediction in identifying the causative allele and clarifying ABO discrepancies.

ABO genotyping was first attempted shortly after the ABO gene was identified in 1990, when PCR-based assays, including PCR-RFLP (restriction fragment length polymorphism), PCR-SSCP (single strand conformation polymorphism), and PCR-SSP (sequence-specific primer), enabled discrimination among the major alleles (A, B, and O).Because various point mutations in exons 6 and 7 underlying subgroup phenotypes were progressively elucidated, these variants also became the targets for genotyping assays. Nevertheless, PCR-based approaches are inherently limited to the detection of predefined variants and require additional allelic separation and direct sequencing to identify alleles corresponding to subgroup phenotypes. Since the 2010s, next-generation sequencing (NGS) has enabled comprehensive analysis of the genetic variation across the entire ABO gene through massively parallel sequencing, helping identify several novel alleles at the population level. On the other hand, its short-read architecture imposes limitations in haplotype phasing. Long-read sequencing technologies have recently been introduced to overcome these limitations and are increasingly being applied, allowing direct analysis of full-length haplotypes and offering advantages in detecting recombination events and characterizing repetitive regions. Although advances in molecular genetics have substantially improved the accuracy and convenience of genotyping methods, their clinical application remains limited.The advantages of serological testing—namely, accessibility, accuracy, and low cost—continue to support its primary role in routine practice. Although ABO genotyping cannot yet replace serological methods, it serves as a valuable complementary tool in resolving discrepant cases and in specialized settings such as organ transplantation. Its clinical utility is expected to expand further as technological advances continue.

ABO/RhD-mismatch transfusions are frequently encountered in clinical practice, so a systematic and thorough understanding of these events is necessary. In the case of ABO minor-incompatible transfusions, it is important to consider the possibility of hemolytic transfusion reactions because of the reaction between the ABO antibodies in the blood product and the patient’s red blood cells. For platelet products, the risk is approximately 1 in 9,000.In ABO major-incompatible transfusions, red blood cell products are contraindicated, but plasma or platelet products may be allowed in situations such as blood product shortages. In RhD major-incompatible transfusions, the use of Rh immunoglobulin to prevent alloimmunization may be considered depending on the patient’s clinical status and the availability of blood products. In the case of RhD major-incompatible red blood cell transfusions, however, such prevention is difficult to apply in Korea. ABO/RhD-mismatch transfusion may also affect the long-term outcomes of patients, in addition to immediate hemolytic transfusion reactions. Therefore, decisions must be made based on the patient’s clinical situation considering the benefits and potential risks.

A 64-year-old male patient diagnosed with B-cell lymphoma required regular platelet transfusions due to persistent thrombocytopenia. Over time, he developed severe transfusion-related allergic reactions, including anaphylaxis, necessitating the use of washed apheresis platelets (W-APLT). However, as the designated blood center was unable to produce W-APLT, the issue was resolved by collaborating with a neighboring blood center to source the product.Key strategies included verifying the patient’s history of transfusion-related anaphylaxis, coordinating the production schedule of blood products, and implementing administrative procedures such as pre-scheduled ambulance transport on the day of transfusion. These measures ensured the timely supply of W-APLT while minimizing the risk of product wastage. As a result, the patient successfully received multiple W-APLT transfusions without further allergic reactions. This case serves as a model for overcoming infrastructure limitations in W-APLT supply through hospital-blood center collaboration, to provide timely and safe blood products to patients at risk of severe transfusion-related allergic reactions and anaphylaxis.

This study reviewed allergic transfusion reactions (ATRs) and the efficacy of pre-transfusion antihistamine (PreTAH) administration. Studies have shown that PreTAH does not prevent all ATRs and provides no significant benefit over non-administration groups. Instead, they may cause sedation, increase the burden on medical staff, and lack cost-effectiveness. Most transfused patients do not experience ATRs; except for anaphylaxis, they pose minimal risk. Thus, the decision to administer PreTAH should carefully weigh the benefits and risks. Routine PreTAH use in all transfusion patients is not recommended. Instead, PreTAH should be reserved for patients with a high risk of allergic reactions based on their medical history and risk factors.

In 2023, blood donations from registered donors at the Korean Red Cross Blood Centers accounted for 72.6% of blood donations from the Korean Red Cross, helping secure blood equivalent to 65.9% of entire blood donations, 87.6% of plasmapheresis, and 95.1% of platelets component donations. The number of newly registered blood donors increased from 94,998 in 2017 to 218,767 in 2023, and 1,928,053 donors were registered as of December 2023. The age distribution of registered blood donors showed that teenagers and people in their 20s accounted for approximately 70% of the total. Nevertheless, additional research on the blood donation status according to the age of new and cumulative registered blood donors is needed to manage blood donation resources.