Serologic profiling of D variants in donor routine: unveiling the impact on false-negative results and alloimmunization.

The high number of D variants can lead to the unnecessary use of Rh immune globulin, overuse of D- RBC units, and anti-D allommunization. D variant prevalence varies among ethnic groups, and knowledge of the main variants present in a specific population, their behavior in serologic tests, and their impact on clinical practice is crucial to define the best serologic tests for routine use. The present study aimed to explore the serologic profile of D variants and to determine which variants are most associated with false-negative D typing results and alloimmunization. Donor samples were selected in two study periods. During the first period, D typing was performed on a semi-automated instrument in microplates, and weak D tests were conducted in tube or gel tests. In the second period, D typing was carried out using an automated instrument with microplates, and weak D tests were performed in solid phase. Samples from patients typed as D+ with anti-D were also selected. All samples were characterized by molecular testing. A total of 37 RHD variants were identified. Discrepancies and atypical reactivity without anti-D formation were observed in 83.4 percent of the samples, discrepant D typing results between donations were seen in 12.3 percent, and D+ patients with anti-D comprised 4.3 percent. DAR1.2 was the most prevalent variant. Weak D type 38 was responsible for 75 percent of discrepant samples, followed by weak D type 11, predominantly detected by solid phase. Among the D variants related to alloimmunization, DIVa was the most prevalent, which was not recognized by serologic testing; the same was true for DIIIc. The results highlight the importance of selecting tests for donor screening capable of detecting weak D types 38 and 11, especially in populations where these variants are more prevalent. In pre-transfusion testing, it is crucial that D typing reagents demonstrate weak reactivity with DAR variants; having a serologic strategy to recognize DIVa and DIIIc is also valuable.

Association of blood group with COVID-19 disease susceptibility and severity in Saudi Arabia.

BACKGROUND: Novel SARS-CoV-2 (COVID-19) virus has rapidly spread worldwide and was declared a pandemic, making identifying and prioritizing individuals most at risk a critical challenge. The literature describes an association between blood groups and the susceptibility to various viral infections and their severity. Knowing if a specific blood group has more susceptibility to COVID-19 may help improve understanding the pathogenesis and severity of the disease. We aimed to assess the association between ABO/RhD and COVID-19 susceptibility and severity, and to compare results with similar studies in Saudi Arabia. STUDY DESIGN AND METHODS: This study was conducted between March and October 2021 on 600 patients confirmed positive for COVID-19 infection. Patients' data were collected and analyzed. As a control, 8423 healthy blood donors were enrolled as a sample representative of the population for blood group distribution. RESULTS: More individuals had blood group B in the COVID-19 group in comparison with the control group (24.2% vs. 18%), The opposite was observed among individuals of group O (39.5% vs. 47.3%). The B blood group was predictive of higher risk of mortality. No significant difference in the distribution of RhD was observed between the COVID-19 and the control groups. Neither ABO nor RhD was significantly associated with the severity of COVID-19. DISCUSSION: Although there was no significant association with the disease severity, the B blood group may be associated with a higher risk for COVID-19 infection. Further studies with a larger sample size are necessary to evaluate this correlation.

Weak D Testing is not Required for D- Patients With C-E- Phenotype.

BACKGROUND: Although testing to detect weak D antigens using the antihuman globulin reagent is not required for D- patients in many countries, it is routinely performed in Korea. However, weak D testing can be omitted in D- patients with a C-E- phenotype as this indicates complete deletion of the RHD gene, except in rare cases. We designed a new algorithm for weak D testing, which consisted of RhCE phenotyping followed by weak D testing in C+ or E+ samples, and compared it with the current algorithm with respect to time and cost-effectiveness. METHODS: In this retrospective study, 74,889 test results from January to July 2017 in a tertiary hospital in Korea were analyzed. Agreement between the current and proposed algorithms was evaluated, and total number of tests, time required for testing, and test costs were compared. With both algorithms, RHD genotyping was conducted for samples that were C+ or E+ and negative for weak D testing. RESULTS: The algorithms showed perfect agreement (agreement=100%; κ=1.00). By applying the proposed algorithm, 29.56% (115/389 tests/yr) of tests could be omitted, time required for testing could be reduced by 36% (8,672/24,084 min/yr), and the test cost could be reduced by 16.53% (536.11/3,241.08 USD/yr). CONCLUSIONS: Our algorithm omitting weak D testing in D- patients with C-E- phenotype may be a cost-effective testing strategy in Korea.

Weak D Testing is not Required for D− Patients With C−E− Phenotype

BACKGROUND: Although testing to detect weak D antigens using the antihuman globulin reagent is not required for D− patients in many countries, it is routinely performed in Korea. However, weak D testing can be omitted in D− patients with a C−E− phenotype as this indicates complete deletion of the RHD gene, except in rare cases. We designed a new algorithm for weak D testing, which consisted of RhCE phenotyping followed by weak D testing in C+ or E+ samples, and compared it with the current algorithm with respect to time and cost-effectiveness. METHODS: In this retrospective study, 74,889 test results from January to July 2017 in a tertiary hospital in Korea were analyzed. Agreement between the current and proposed algorithms was evaluated, and total number of tests, time required for testing, and test costs were compared. With both algorithms, RHD genotyping was conducted for samples that were C+ or E+ and negative for weak D testing. RESULTS: The algorithms showed perfect agreement (agreement=100%; κ=1.00). By applying the proposed algorithm, 29.56% (115/389 tests/yr) of tests could be omitted, time required for testing could be reduced by 36% (8,672/24,084 min/yr), and the test cost could be reduced by 16.53% (536.11/3,241.08 USD/yr). CONCLUSIONS: Our algorithm omitting weak D testing in D− patients with C−E− phenotype may be a cost-effective testing strategy in Korea.

Report on External Proficiency Testing for the ABO and D Blood Group Typing Tests in Blood Centers (2014) / 대한수혈학회지

BACKGROUND: Korean Blood Safety Commission has implemented external proficiency testing (PT) for blood grouping test (BGT) to help improve the quality of blood centers since 2011. We analyzed the results of 2014 PT for BGT to help in planning the future PT for BGT and to improve the quality of blood centers. METHODS: Whole blood survey samples including three panels for ABO grouping and three panels for D typing were sent to 69 institutes. Evaluation criteria for BGT were as follows: 'Good' for answers matched with intended results, 'Acceptable' for correct answers other than that of 'Good', 'Unacceptable' for answers other than those of 'Good+acceptable' as correct answers; and 'Not graded' for answers in case of different answers in the two standard laboratories. RESULTS: All of the answer rates of 'Good' for D typing were 100%. However, the answer rates of 'Good' for cell typing, serum typing and interpretation for 14-ABO-2 samples with discrepant result between cell typing and serum typing were 39.1%, 29%, and 47.8%, respectively. Those of 'Unacceptable' for cell typing and interpretation for 14-ABO-2 samples were 2.8% and 1.4%. CONCLUSION: Because the answer rates of ABO grouping for samples with discrepant result between cell typing and serum typing were not high, education for this case is needed. Diversity of materials for PT would be necessary for more accurate evaluation of the performance of BGT in blood centers.

Report on External Proficiency Testing for the ABO and D Blood Typing in Blood Centers in 2012 and 2013 / 대한수혈학회지

BACKGROUND: It was reported that a continuous education program and external proficiency testing (PT) for blood grouping test (BGT) might be necessary because some blood centers of medical institutions could not correctly examine ABO subtype and D variant, according to the results of the first year project in 2011. Therefore, the results of PT for BGT in blood centers in 2012 and 2013 were compared to those in 2011 in order to assess the impact of projects during a period of three years and to help in planning the future PT for BGT. METHODS: Whole blood survey samples composed of three panels for ABO grouping and three panels for D typing were sent to 74 and 71 institutes in 2012 and 2013, respectively. Evaluation criteria for BGT were as follows: 'Good' for the answers matched with intended results, 'Acceptable' for the correct answers other than that of 'Good', and 'Unacceptable' for the answers other than those of 'Good+acceptable' as correct answers. RESULTS: The answer rates of 'Unacceptable' for ABO subtype were 1.4% in 2012 and 4.2% in 2013. However, the answer rate of 'Good' increased from 44.6% in 2012 to 83.1% in 2013. The answer rate of 'Unacceptable' for D variants showed a marked decrease, from 16.2% in 2012 to 1.4% in 2013. CONCLUSION: Projects for PT for BGT during a period of three years have improved laboratory quality in blood centers. However, the acquisition and change of the materials for PT would be necessary in order to continuously and practically provide help to blood centers.

A Case of Partial-D Category Va / 대한수혈학회지

The patient, a 65-year-old woman, was admitted for chronic subdural hematoma. ABO and Rh blood typing were performed as a pre-operation test. Her red blood cells were not agglutinated with anti-D reagent (Ortho Diagnostic System, USA). But they were positive in subsequently performed weak-D test and also agglutinated with three other anti-D reagents (Baxter Dade, USA; Biotest Diagnostics, Korea; Bioscot Ltd., UK). The patient s Rh phenotype was CcDe. Antibody screening test, direct and indirect antiglobulin tests showed negative results. Different reactivity to various anti-D reagents as shown in this case suggested that her cells have partial-D antigen which lack one or more components of the Rh D antigen. We considered that this case was category Va according to the reactivity patterns of monoclonal anti-D antibodies with various partial- D cells.