Immunohematology最新文献

A person who has achieved the Specialist in Blood Banking (SBB) certification is a medical laboratory scientist who receives advanced training in blood banking and transfusion medicine and has passed an examination given by the American Society for Clinical Pathology. There are several pathways or "eligibility routes" to qualify for the examination to obtain SBB certification, with the most common route involving enrollment in a Commission on Accreditation of Allied Health Education Programs-accredited SBB program. The goal of this study was to compile information about the current accredited SBB programs in the United States and SBB exam statistics for purposes of assessing changes in the programs and detecting trends in SBB exam takers and pass rates. SBB program coordinators were surveyed about qualitative and quantitative aspects of their programs. Current data, changes over time, and nationally available data were tabulated for comparison. This information may be helpful for all medical laboratory scientists interested in considering further studies and certification in blood banking and transfusion medicine.

RH allele variability is caused by several types of variants, resulting in altered RhD and RhCE phenotypes. Most of the weak D phenotypes in European-derived populations are weak D types 1, 2, or 3, which are not involved in alloimmunization episodes. However, the Brazilian population is racially diverse, and the accuracy of molecular and serologic tests developed in recent years has allowed for the identification of other RH variants, that are common in the Brazilian population, such as weak D type 38 or weak partial 11, the latter involved in alloimmunization cases. Furthermore, patients with these two weak D variants must be transfused with D- red blood cell units, as do patients with weak D type 4 or DAR, which are also common D variants in Brazil. Weak D type 38 and weak partial 11 can be serologically misclassified as weak D types 1, 2, or 3 in patients, based on European experience, or as D- in donors. Additionally, pregnant women may unnecessarily be identified as requiring Rh immune globulin. RhCE phenotypes are reliable indicators of RhD variants. For individuals with the Dce phenotype, the preferred approach is to specifically search for RHD*DAR. However, when encountering DCe or DcE phenotypes, we currently lack a developed method that assists us in rapidly identifying and determining the appropriate course of action for the patient or pregnant woman. Two multiplex assays were proposed: one for the identification of RHD*weak partial 11, RHD*weak D type 38, and RHD*weak D type 3 and another for RHD*weak D type 2 and RHD*weak D type 5. The multiplex assays were considered valid if the obtained results were equivalent to those obtained from sequencing. Expected results were obtained for all tested samples. The proposed multiplex allele-specific polymerase chain reaction assays can be used in the molecular investigation of women of childbearing age, patients, and blood donors presenting a weak D phenotype with DCe or DcE haplotypes in a mixed-race population, such as Brazil.

Sc1 is a high-prevalence blood group antigen that is part of the Scianna blood group system. The clinical significance of Scianna antibodies is not well understood because of their rarity; there are only a handful of cases in the literature. This scarcity of information can make it difficult to decide on the best course of action when transfusing a patient with alloantibodies to Scianna blood group antigens. We describe a case of an 85-year-old woman presenting with melena and a hemoglobin of 66 g/L. Upon request for crossmatched blood, a panreactive antibody was found, later elucidated to be alloanti-Sc1. Because of the urgent nature of the transfusion, the patient was transfused with 2 incompatible, presumed Sc1+, red blood cell units with no evidence of an acute or delayed transfusion reaction. This case has been shared with the International Society of Blood Transfusion Rare Donor Working Party, via their Outcome of Incompatible Transfusion form, and adds to the body of evidence on clinical significance of antibodies to the antigens of the Scianna blood group system.

It has long been a goal of transfusion medicine scientists to predict which patients will make clinically significant antibodies when transfused with donor red blood cells (RBCs). But this goal has yet to be achieved. Not all patients have an adverse response to an RBC transfusion by making an antibody to an RBC antigen, and for patients who do, in most cases, they form antibodies to common antigens for which provision of antigen-negative RBCs is not difficult. However, for patients who make antibodies to many antigens and for patients who make an antibody requiring rare blood that is negative for a high-prevalence antigen, knowing the clinical significance of that patient's antibody is important for effective and timely transfusion. This review of the literature provides information on the monocyte monolayer assays (MMAs) developed to predict the outcome of incompatible RBC transfusion. One of these assays has been used for almost 40 years in the United States to predict the outcome of RBC transfusion in patients with alloantibodies for whom provision of rare RBCs is very difficult. Because all transfusion medicine facilities and blood centers will not likely implement the MMA, it is important that the selection of the referral laboratory be carefully made. The MMA is a proven test in the prediction of incompatible transfusion outcomes in patients with IgG-only antibodies. It has been helpful in decision-making when rare blood components are not available or not available quickly, although decisions on blood transfusion must be made by the physician attending the patient and blood should not be withheld waiting for the MMA result in an urgent situation.

Blood transfusions are a common medical treatment. Risks arise when compatible blood is not available. This study assesses the correlation between antibody reaction strength at the antihuman globulin (AHG) phase of testing and the antibody clinical significance as predicted using the monocyte monolayer assay (MMA). Multiple examples of anti-K donor plasma samples were selected to sensitize K+k+ red blood cells (RBCs). Reactivity was confirmed by testing the sensitized K+k+ RBCs at saline-AHG. Antibody titers were determined by serial dilution using neat plasma. Sixteen samples were selected for the study based on comparable graded reactions with neat plasma (1+, 2+, 3+, and 4+) and similar titration endpoints. Each sample was used to sensitize the same Kk donor and then tested by monocytes to evaluate the clinical significance using the MMA, an in vitro procedure that mimics in vivo extravascular hemolysis to predict the survivability of incompatible transfused RBCs. The monocyte index (MI), i.e., the percentage of RBCs adhered, ingested, or both versus free monocytes, was calculated for each sample. Regardless of the reaction strength, all examples of anti-K were predicted to be clinically significant. While anti-K is known to be clinically significant, the immunogenicity rate of K ensures ample supply of antibody samples for inclusion in this project. This study demonstrates that in vitro antibody strength is highly subjective and variable. These results show no correlation between graded reaction strength at AHG and the predicted clinical significance of an antibody as assessed using the MMA.

This update of the Landsteiner-Wiener (LW) blood group system (Grandstaff Moulds MK. The LW blood group system: a review. Immunohematology 2011;27:136-42. Storry JR. Review: the LW blood group system. Immunohematology 1992;8:87-93) reports new information on the distribution of genetic variants in ICAM4 and reviews the complex serologic identification of the high-prevalence LWEM antigen. The role of ICAM4 in sickle cell disease and malaria susceptibility is discussed.