Extended Red Blood Cell Genotyping to Investigate Immunohematology Problems

[External Quality Control in Immunohematology of National Medical Center's Blood Bank. History and present]

For the proper functioning of the Immunohematology Area, an External Quality Control was established since 1973 through a program that evaluates the performance of the laboratories of the Blood Bank and transfusion services that carry out immunohematology tests. This program consists of sending panel cells to participating blood banks or services, which are phenotyped erythrocyte samples previously studied as problem cases but whose results are unknown by the participating laboratories. The processes in which the program is of most importance are determination of the ABO group, determination of Rh, performance of the direct and indirect Coombs test, and pre-transfusion compatibility tests. It was carried out an observational and retrospective study of the results obtained in the 2020 period from 104 units participating in the Immunohematology Quality Control Program of the National Medical Center's Blood Bank. A panel of cells was sent for external quality control of immunohematology every 45 days, resulting in 9 panels for each unit in the studied period. Compliance with the program was observed in the general result (79.6%), i.e., there was a decrease in the participation of the registered units. Of a maximum score of 100% to be obtained, it was observed a general result of 95.3% compliance of the participating units. The results obtained confirm the good general training of the immunohematology laboratories of the participating units. Yet, as in any external control program, it becomes clear that obtaining an erroneous result is a risk that can occur in any laboratory.

Frequency of Extended Red Cell Antigen Phenotype Among Patients of Hematological Diseases: A Single Center Study

Background

Alloimmunization of erythrocytes is a major problem in patients with hematological diseases that require frequent blood transfusions. Matching of extended red cell antigens of Kell, MNS, Kidd, and Duffy can decrease the risk of alloimmunization. Hence, in this study, the frequencies of the extended red cell phenotypes were explored.

Objective

To find out the frequency of extended red blood cell antigen phenotypes among patients with hematological diseases.

Methods

This cross-sectional research study was performed on 488 patients diagnosed with hematological diseases who required blood transfusion at the National Institute of Blood Disease and Bone Marrow Transplantation Karachi for a period of 1.42 years from November 2019 to March 2021. The blood of patients was analyzed for antigen phenotypes of different blood group systems including Kell, MNS, Kidd, and Duffy. The data obtained were interpreted.

Results

Among the 488 patients, 284 (58.20%) patients were male, and 204 (41.80%) patients were female with a mean age of 8.1 years. Beta thalassemia was the most common hematological disease reported in 354 (72.5%) of the patients. The most common blood group was O positive reported in 182 (37.3%) of the patients followed by B positive blood group in 124 (25.4%). The frequencies of extended red cell antigen phenotypes in the patients were K antigen 14 (2.9%), Kp^a antigen 26 (5.3%), Kp^b antigen 424 (86.9%), Fy^a antigen 360 (73.8%), Fy^b antigen 260 (53.3%), Jk^a antigen 294 (60.2%), Jk^b antigen 326 (66.8%), M antigen 410 (84.0%) and N antigen 306 (62.7%).

Conclusion

Beta thalassemia was the most common hematological disease followed by iron deficiency anemia, aplastic anemia, and acute leukemia. Patients with hematological diseases had a higher prevalence of Kp^b antigen followed by M, Fy^a, Jk^b, N, Jk^a, Fy^b, Kp^a, and K antigen. O positive was the most frequent blood group followed by B positive, A positive and AB positive blood group.