Discovered by Karl Landsteiner in 1900, the ABO blood type is the most important blood type for transfusions [1]. For safe blood transfusions, cell type and serum type test results of the patient should match. If the results of the tests are inconsistent, we call it ABO discrepancy. It is essential to resolve ABO discrepancies in clinical laboratories for safe blood transfusion [2]. Weak ABO subgroups are the main cause of ABO discrepancy. Various genotyping methods can be used to con rm the ABO blood group. Recently, next-generation sequencing has been used for blood grouping. However, this technique is expensive [3]. Here, we describe a weak B phenotype harboring B101/O04-variant alleles observed in a Korean family, and suggest a practical algorithm to work-up ABO subgroups without using whole-genome sequencing. The

Background: Apolipoprotein E (APOE ) genotyping is an important test for predicting the risk of Alzheimer's and cardiovascular disease. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique for APOE genotyping is not widely used due to the need for special gels. Thus, this study aimed to develop an PCR-RFLP technique to overcome this problem. Methods: For high-resolution agarose gel electrophoresis of PCR-RFLP, a general-purpose agarose gel, lithium borate buffer (LBB), and high voltage were used. After electrophoresis, the change in the temperature of electrophoresis buffer was measured. We performed PCR-direct sequencing to confirm the results of the PCR-RFLP of genomic DNA extracted from 103 K 2 EDTA-treated venous blood samples. Results: When a small gel 6 cm in length was run at 300 V for 50 minutes in an electrophoresis chamber with a distance of 20 cm between electrodes, the target bands could be easily discriminated and only slight deformities of the bands were observed. The change in the temperature of the buffer was 14℃. The results obtained with PCR-RFLP were in complete agreement with those of PCR-direct sequencing. Conclusions: PCR-RFLP with electrophoresis using a general-purpose agarose gel, LBB, and high voltage is an accurate and reliable assay for APOE genotyping. Additionally, general-purpose agarose gel with LBB can be used in place of polyacrylamide or MetaPhor agarose gel for resolving small DNA fragments.

Background: Kidd (SLC14A1 rs1058396) genotyping is an important test to prevent delayed hemolytic transfusion reactions and hemolytic disease of the fetus or newborn. The PCR-restriction fragment length polymorphism (RFLP) technique using the MnlI restriction enzyme is not used widely because of the need for a polyacrylamide gel. PCR-RFLP was performed by electrophoresis with general-purpose agarose gel, and lithium borate buffer (LBB) was developed as a replacement for polyacrylamide gel. Methods: Seventy-two venous blood samples were collected randomly and used in this study. A 3% agarose gel containing 1 µg/mL of ethidium bromide and 1 mM LBB, and a high-voltage (300 V) were used to separate the short-length restriction fragments (72 bp, 51 bp, 36 bp, and 21 bp). The PCR-RFLP results were confirmed by PCR-direct sequencing. Results: Target restriction fragments could be easily discriminated. The results obtained with the PCR-RFLP were completely in agreement with the results of PCR-direct sequencing. Conclusion:The PCR-RFLP using a general-purpose agarose gel and LBB is an accurate and reliable assay for Kidd genotyping.