Immunohaematological Tests Research Articles

Role of dithiothreitol in the resolution of pretransfusion immunohematology testing in patients receiving the anti-CD38 monoclonal antibody daratumumab for the treatment of multiple myeloma

Abstract: INTRODUCTION: Daratumumab (Darzalex; Janssen-Cilag Pty Ltd), an anti-CD38 monoclonal antibody (MoAb), has demonstrated high efficacy in treating relapsed and refractory multiple myeloma (MM). It stands as the pioneering anti-CD38 MoAb approved by the US FDA (2015) and TGA Australia (2017). While targeting CD38 on myeloma cells, daratumumab poses a challenge in pretransfusion testing by inducing panreactivity in indirect antiglobulin tests (IATs) due to CD38 expression on red cells. This study investigates the role of dithiothreitol (DTT) in resolving pretransfusion immunohematology testing in patients treated with daratumumab for MM. MATERIALS AND METHODS: Pretransfusion samples from three hematological patients diagnosed with MM and receiving anti-CD38 drugs necessitating red cell transfusion were subjected to immunohematology serological testing. Clinicians provided patient information, including gender, age, transfusion history, and time between anti-CD38 MoAb infusion and sample collection. Tests included ABO/RhD typing, IAT, both polyspecific and monospecific direct antiglobulin test (DAT), antibody (Ab) screening, Ab identification, eluate preparation, and red cell crossmatch. Control tests were conducted by incubating patient samples at 37°C for 1 h. RESULTS: ABO/RhD typing remained unaffected, yet all samples exhibited panreactivity in IATs. Two samples showed positive DAT results but negative eluates. Treatment of reagent red blood cells (RBCs) with 0.2 M DTT effectively mitigated interference by anti-CD38 monoclonal antibodies, resulting in compatible red cell crossmatches. Notably, incubation of patient samples at 37°C for 1 h yielded identical results. CONCLUSION: Pretreatment of erythrocytes with DTT deactivated the CD38 antigen, eliminating reactivity with patient serum treated with daratumumab. DTT treatment of reagent RBCs emerges as an efficient and accessible strategy to counteract interference from anti-CD38 drugs in pretransfusion tests.

The effects of drone transportation on routine laboratory, immunohematology, flow cytometry and molecular analyses.

Transportation of medical samples between laboratories or hospital sites is typically performed by motorized ground transport. Due to the increased traffic congestions in urban environments, drone transportation has become an attractive alternative for fast shipping of samples. In accordance with the CLSI guidelines and the ISO 15189 standard, the impact of this transportation type on sample integrity and performance of laboratory tests must be thoroughly validated. Blood samples from 36 healthy volunteers and bacterial spiked urine samples were subjected to a 20-40 min drone flight before they were analyzed and compared with their counterparts that stayed on the ground. Effects on stability of 30 routine biochemical and hematological parameters, immunohematology tests and flow cytometry and molecular tests were evaluated. No clinically relevant effects on blood group typing, flow cytometry lymphocyte subset testing and on the stability of the multicopy opacity-associated proteins (Opa) genes inbacterial DNA nor on the number of Abelson murine leukemia viral oncogene homolog 1 (abl) housekeeping genesin human peripheral blood cells were seen. Forthreeofthe 30 biochemistry and hematology parameters a statistically significant difference was found: gamma-glutamyl transferase (gamma-GT), mean corpuscular hemoglobin (MCH) and thrombocyte count. A clinically relevant effect however was only seen for potassium and lactate dehydrogenase (LDH). Multi-rotor drone transportation can be used for medical sample transportation with no effect on the majority of the tested parameters, including flow cytometry and molecular analyses, with the exception of a limited clinical impact on potassium and LDH.

'Old is gold' does conventional test tube method still reign supreme? An immuno-haematological survey of anti-D detection and titration in ante-natal cases among major hospitals across India.

Anti-D detection and titration plays a major role in RhD negative antenatal cases both, for monitoring maternal as well as fetal status as well as initiation of early therapeutic interventions, such as intra-uterine transfusions (IUT) to improve maternal as well as fetal morbidity and mortality and reduce the adverse effects of haemolytic disease of fetus and newborn (HDFN). We conducted a survey focusing on the policies and procedures of anti-D detection and titration among major tertiary care centres across India. The survey was drafted by a working group of transfusion medicine and immunohematology specialists from six different centres in India. Data were obtained via the use of an online questionnaire. Results were categorised into four categories, Hospital information, immuno-haematological testing methodology, clinical significance of anti-D testing and the role of transfusion medicine specialists. The survey highlighted the modalities as well as the methodologies of anti-D detection and titration in antenatal women across different major tertiary care centres in India. This survey provided a unique snapshot of the prevalent methodologies being employed by major tertiary care centres across the country for detection and titration of anti-D levels as well as the important role it plays in the therapy of affected antenatal women to minimise adverse effects on the fetus.

A national survey of current immunohematologic testing practices for the diagnosis of autoimmune hemolytic anemia in India.

Autoimmune hemolytic anemia (AIHA) is a common term for several disorders that differ from one another in terms of etiology, pathogenesis, clinical features, and treatment. Management of patients with AIHA has become increasingly evidence-based in recent years. While this development has resulted in therapeutic improvements, it also carries increased requirements for optimal diagnosis using more advanced laboratory tests. Unfortunately, limited data are available from developing countries regarding the testing and transfusion management of patients with AIHA. The main objective of this survey was to explore the current immunohematologic testing practices for the diagnosis of AIHA in India. This online survey consisted of 30 questions, covering the place of work, the number of AIHA cases encountered in the 3 preceding years, testing method(s), transfusion management, and so forth. Individuals representing 89 laboratories completed the survey; only 78 of which responded that AIHA testing was performed in their facility's laboratory. The majority of respondents agreed that the most commonly affected age-group comprised individuals of older than 20 years, with a female preponderance. Regarding transfusion management, respondents indicated that transfusion with "best-match" red blood cell units remains the most common practice. Column-agglutination technology is used by 92 percent of respondents as the primary testing method. Although a monospecific direct antiglobulin test is available at 73 percent of the sites, most of them have limited access to other resources that could diagnose cold or mixed AIHA. Merely 49 percent of responding laboratories have the resources to perform adsorption studies for the detection of alloantibodies. Furthermore, three-cell antibody screening reagents are unavailable at 32 percent of laboratories. In 72 percent of centers, clinical hematologists would prefer to consult a transfusion medicine specialist before administering treatment to AIHA patients. There is unanimous agreement regarding the need for a national registry. The survey data indicate wide variability in testing practices for patients with AIHA in India. Future studies are needed to focus on the feasibility and cost-effectiveness of different testing strategies for developing countries.

Case report of anti JMH: A high-titer, low-avidity antibody posing difficulty in immunohematological tests

This report presents a patient with anti-John Milton Hagen (JMH) posing difficulties in the immunohematological test in the Blood Bank Unit of Universiti Kebangsaan Malaysia Medical Center. A 1-year-8-month-old boy was referred to our center to rule out acute leukemia from a private hospital. A crossmatch request was sent to the Blood Bank before the bone marrow biopsy. Our testing revealed his blood grouping as O Rh-D positive. His Direct Antiglobulin Test was positive, and his antibody screening and antibody identification showed weak pan-reactivity. However, reactions were negative with enzyme-treated cells. Red cell elution showed interestingly no reaction in the eluate, suspected to be due to drug-induced autoantibody. Further tests of antibody titration and neutralization test suggest it could be a high-titer low avidity (HTLA) antibody, most likely Anti-JMH. Although HTLA antibodies are clinically insignificant, they can cause confusion and delay in issuance of blood products. There are also cases of clinically significant HTLA antibodies. Determining the type of HTLA antibody may guide the extent of further testing required to utilize resources best and, most importantly, to assure patient safety.

The importance of removing interference caused by Darzalex® (daratumumab) in pre-transfusion testing

Introduction: Multiple myeloma (MM) is a hematologic malignacy characterized by the uncontrolled proliferation of abnormal plasma cells in the bone marrow. Darzalex® (daratumumab) has emerged as a highly effective therapeutic agent for MM, offering an additional treatment option for patients who have developed resistance to other therapies. However, the use of Darzalex® poses challenges in pre-transfusion testing due to its strong binding affinity of the monoclonal anti-CD38 antibody to CD38 protein, resulting in panreactivity with test erythrocytes and complicating the detection of erythrocyte alloantibodies. The objective of this case report is to outline the procedures, significance, and methodologies for mitigating this interference using the DaraEx® reagent. Case Report: We present the cases of three patients diagnosed with MM and treated with Darzalex® at our institution in 2023. Following the administration of Darzalex®, all three patients exhibited positive results on indirect antiglobulin tests (IAT). Cross-matching tests conducted with red blood cell concentrates also yielded positive results, with strengths ranging from 2+ to 3+. To eliminate interference, we used a specific DaraEx® reagent that utilizes Fab fragments of anti-CD38 to mitigate interference by masking CD38 on the cell surface. Subsequent application of this reagent resulted in negative IAT results for all three patients. However, one patient still displayed a weakly positive cross-matching test (<1+), suggesting that complete elimination of interference may not always be achievable with the DaraEx® method. Conclusion: Despite the availability of reliable methods such as dithiothreitol and the DaraEx® reagent for mitigating interference, complete success in eliminating interference remains elusive. This underscores the importance of implementing proactive measures to prevent interference. Patients undergoing Darzalex® therapy should undergo comprehensive immunohematological testing before medication administration. Given the increased need for blood transfusions in MM patients, ensuring the compatibility of blood products is essential for safe transfusion practices.

Pretreatment with Daudi cells eliminates anti-CD47 monoclonal antibody interference in immunohematology testing.

Anti-CD47 monoclonal antibodies have increasing clinical applications in the treatment of cancer. However, anti-CD47 monoclonal antibodies interfere with immunohematology testing in patients who require blood transfusion. As the current approaches to removing any interferences have technical problems, new methods need to be developed to resolve anti-CD47 interference in immunohematology testing. We evaluated the Daudi cell line for the adsorption of free anti-CD47 monoclonal antibodies from patients' plasma to facilitate immunohematology testing in patients treated with anti-CD47 monoclonal antibody. CD47 expression was identified on the Daudi cells using flow cytometry and confocal microscopy. Next, we tested the ability of intact Daudi cells mixed with simulating plasma and clinical samples to achieve efficient removal of interfering anti-CD47 monoclonal antibodies. The indirect antiglobulin test was used to verify whether interference from anti-CD47 monoclonal antibodies in plasma was eliminated and whether the detection of other irregular antibodies was affected. The effect of eliminating interference was also investigated in relation to the time that the Daudi cells were stored after having been fixed with paraformaldehyde. CD47 expression was higher on Daudi cells than on red blood cells. Analysis of the indirect antiglobulin test results revealed that anti-CD47 monoclonal antibody-treated patients' plasma absorbed by Daudi cells for 15 min at 37°C could completely prevent the interference of anti-CD47 monoclonal antibodies in immunohematology testing while the detection of the tested antibodies, including anti-D and anti-K, was unaffected. By decreasing the incubation time, we discovered that interferences in samples with agglutination strengths below 2+ could be eliminated after incubation for 5 min. Of importance, Daudi cells can be preserved with 4% paraformaldehyde for 14 days as short-term storage reagents. This is the first study in which Daudi cells were used to effectively resolve the interference of anti-CD47 monoclonal antibodies in pretransfusion tests.

Prevalence and identification of irregular erythrocyte antibodies in voluntary blood donors in the territory of southeast Serbia

Background/Aim. The purpose of tests for transmittable diseases, as well as determining ABO group, Rh typing, and the presence of clinically significant erythrocyte antibodies, is to enable the appropriate selection of blood/blood components for transfusion, to prevent or minimize adverse effects of transfusion, and to identify donors whose units of blood/components are not suitable for transfusion. The aim of the study was to evaluate the presence of irregular erythrocyte antibodies as well as to determine the specificity and origin of these antibodies in voluntary donors. Methods. This prospective observational study, conducted from January until July 2023, included samples of voluntary blood donors (BDs) for antibody screening in the population of voluntary BDs in the territory of Southeast Serbia. A total of 23,082 samples from healthy BD were examined through this period. Results. The overall prevalence of irregular anti-erythrocyte antibodies was 0.1125%, with anti-K, anti-D, and anti-E being the most frequently identified alloantibodies. Out of a total of 26 donors with positive screening results, 11 (42.32%) had alloantibodies, and 15 (57.68%) had antibodies of undetermined specificity. A positive antibody test was observed more frequently in male donors, and the age range of 51 years and above accounted for the majority of positive cases. Conclusion. Immunohematological testing, including antibody screening in voluntary BDs, is important for safe blood transfusion and is of great clinical importance. Likewise, it reduces the risk of complications due to incompatible transfusions.

A Rare Case of Pregnancy-induced Anti-D, Anti-C, and Anti-G Antibodies

ABSTRACT A 39-year-old female with breast carcinoma presented with complaints of menorrhagia and weakness. At current admission, her hemoglobin was 6.2 g/dL, and a requisition for packed red blood cells (PRBCs) was sent to the blood center. There was no previous history of transfusions, and the last pregnancy was 11 years ago. During the immunohematological (IH) workup, she was typed as O, ccdee, with an extra reaction in reverse grouping. Her antibody screening was positive, followed by the antibody identification, which was suggestive of anti-D and anti-C antibodies. The “Rhesus G” is an immunogenic antigen that is present on red cells that are D- and/or C-positive. Therefore, it is essential to determine the possibility of the presence of an anti-G antibody in the patient since anti-G appears as anti-D + anti-C serologically. In our case, a series of IH tests were performed, which ultimately led to the detection of all three antibodies: anti-D, anti-C, and anti-G. The patient’s husband and both children were typed as A, CcDee. Hence, her alloantibodies were most probably pregnancy induced, and since antibodies to the Rhesus system have a poor evanescence phenomenon, they are persisting to date. She was safely transfused with two units of O, ccdee PRBCs, and a special blood group card was provided to ensure that she always receives transfusions with phenotype-matched red cells in the future to avoid further alloimmunization.

A study on diagnostic performance of different immunohematological diagnostic tests in assessing the prevalence of ABO Hemolytic Disease of Newborn in the antenatal O group mothers and their neonatal outcome in a tertiary care hospital in Northern India

BackgroundHemolytic disease of the newborn (HDN) results in the decreased lifespan of the red cells. HDN related to ABO incompatibility is mostly unnoticed because routine screening is not being done. This study was done to assess the prevalence of ABO-HDN and to compare different immunohematological tests. Methods-In this study 213 O group mothers and the 122 ABO-incompatible newborns born to them were included. Quantifying the maternal IgG anti-A/anti-B antibody titer was done by Conventional Tube Technique (CTT) using Dithiothreitol (DTT) pretreated maternal serum. Hemolysin test was performed on the mothers having titer > 256. These cases were followed up and, after delivery, were monitored for ABO HDN, along with direct antiglobulin testing and elution studies. The prevalence of ABO-HDN was calculated, and the different diagnostic parameters of the tests were calculated. Results- The prevalence of ABO-HDN in our population was estimated to be 1.7%, 6.1% & 10.6% in our population, O group mothers, and O group mothers with ABOincompatible newborns, respectively. Maternal titer≥ 512 strongly correlated with ABOHDN. DAT positivity is a good predictor of ABO-HDN, especially using sensitive techniques. Maternal IgG titers have the highest sensitivity & Negative Predictive Value, while DAT has the highest specificity & Positive Predictive Value. Conclusion – Maternal ABO antibody titration may be advocated in the centers to identify high-risk groups. It can advocate institutional delivery and dedicated follow-up of newborns with ABO-HDN. Blood grouping & DAT may be performed in all newborns born to O blood group to identify high-risk cases.

Cold Agglutinin Disease: Challenges in the Serological Workup and Management

Abstract Cold agglutinin disease (CAD) is a rare autoimmune hemolytic anemia associated with autoantibodies that react mainly in the cold. CAD can interfere with immunohematology tests. We report two cases of CAD presented initially as blood grouping discrepancy leading us to further workup. Case I was a 61-year-old female with symptoms of weakness, bone pain, and difficulty breathing with laboratory findings of high cold agglutinin titers of 1:1024. Bone marrow aspirate revealed a mixture of >30% plasma cell and plasma blast. Bone marrow biopsy revealed an interstitial, focal, and nodular pattern of involvement by plasma cells, leading to the diagnosis of plasma cell dyscrasias. Case II analyzed was benign CAD with cold agglutinin titers of 1:64, with no other abnormality. Both patients were managed successfully. We report serological and clinical findings of two CAD cases with similar serological findings but different clinical outcomes.

Immuno-hematological tests at the blood transfusion Center: Experience of the Avicenne military hospital in Marrakesh

Blood transfusion is a therapeutic act that consists in administering blood or one of its cellular or plasma components, from one or more healthy subjects called "donors" to a sick subject called "recipient”. Blood safety is ensured by controlling all stages of the transfusion chain, from blood collection, preparation and biological qualification to the performance of the transfusion act and even the follow-up of the recipients. The basis of immuno-hematological safety is the compatibility between the erythrocyte characteristics of the donor and those of the recipient. From an immuno-hematological point of view, all the antigens present on the surface of an individual's red blood cells determine the erythrocyte phenotype. Only a limited number of erythrocyte antigens that make up this erythrocyte phenotype are sought in current practice. Only a perfect knowledge of the phenotypic and molecular immune-hematological data of donors and recipients will allow to determine the true perimeter of transfusion safety. On this basis, our work focuses on the feasibility of immune-hematological examinations in blood transfusion.

Significance of immunohematologic testing in mother and newborn ABO incompatibility.

The aim of this study was to define risk factors for jaundice and anemia in newborns with a positive direct antiglobulin test (DAT) and/or with an incompatible crossmatch due to ABO incompatibility between mother and newborn. ABO incompatibility has become a more significant cause of hemolytic disease of the fetus and newborn since the introduction of effective anti-D prophylaxis. The condition is common and, if clinically significant at all, causes only mild jaundice, which can be treated with phototherapy (PT). However, rare and serious presentations, requiring transfusion therapy, have been noted. Clinical, laboratory, and immunohematologic data were collected retrospectively from medical records of ABO-incompatible newborns and their mothers over a 5-year period (2016-2020) from University Hospital Centre Zagreb. Two groups of newborns were compared: those who needed medical intervention because of hyperbilirubinemia or anemia and those who did not. Within the group of newborns requiring intervention, we also compared those with A and B blood groups. Over the 5-year period, 72 of 184 (39%) newborns required treatment. The treatment was PT in 71 (38%) newborns and erythrocyte transfusion in 2 (1%). In 112 (61%) newborns, ABO incompatibility was an accidental finding while performing blood group typing; these newborns did not require any therapy. In conclusion, we found a statistical, but not clinically significant, difference between the groups of treated and untreated newborns, related to the mode of delivery and DAT positivity within hours of delivery. There were no statistically significant differences in characteristics between the groups of treated newborns, except for two newborns with blood group A who received erythrocyte transfusions.

Direct antiglobulin test-negative autoimmune hemolytic anemia associated with erythropoiesis stimulating agent resistance in a CKD patient with IgG4-related disease: A case report

Rationale: Direct antiglobulin test (DAT)-negative autoimmune hemolytic anemia (AIHA) is an important differential diagnosis for erythropoiesis-stimulating agents-resistant renal anemia with hemolysis. Patient concerns: An 82-year-old female with a past medical history of diabetes, end-stage kidney disease (estimated glomerular filtration rate: 6.9 mL/min/1.73 m2), post-transcatheter aortic valve implantation, and IgG4-related retroperitoneal fibrosis on prednisolone therapy was referred to our department for assessment of severe anemia. The patient underwent immunohematological testing for serological evaluation. Diagnoses: DAT-negative AIHA and IgG4-RD was established based on DAT-negative and immunohematological tests. Interventions: Glucocorticoid was administered to the patient. Outcomes: The patient’s condition including hemoglobin level was relieved. Lessons: In chronic kidney disease, AIHA may contribute to the development of severe anemia and erythropoiesis-stimulating agents-resistance, irrespective of the results of Coombs test. Reticulocytosis, undetectable haptoglobin and a fall in hemoglobinA1c despite sustained hyperglycemia may be a clue to the diagnosis of hemolysis.

Role of direct antiglobulin test in assessing the severity of extravascular hemolysis in autoimmune hemolytic anemia – analysis from a cross-sectional study

Background: Autoimmune hemolytic anemia (AIHA) is an immune hemolytic disease characterized by hemolysis and anemia which results from increased red cell destruction due to auto antibodies directed against self-antigens on red cells. Clinical characteristics and potential associated hemolysis in AIHA can greatly depend on the serological characteristics. Aims and Objectives: This study was done to find out the association of Grade of polyspecific Direct Antiglobulin test (DAT), complement involvement and immunoglobulin G (IgG) subclass with severity of hemolysis in an AIHA patients. Materials and Methods: This was a cross-sectional study conducted for a period of 18 months from March 1, 2012, to August 31, 2013. Fifty consecutive AIHA patients diagnosed by a positive DAT in EDTA anticoagulated blood samples using poly specific anti human globulin reagent were followed up and results of various immunohematological tests such as polyspecific and monospecific DAT, IgG subtyping, and thermal amplitude were performed. Hematological and biochemical parameters such as hemoglobin, percentage of reticulocyte, total serum bilirubin, and serum lactate dehydrogenase also were recorded. Data were analyzed using SPSS v17. Results: Majority of patients were belonging to 31–40 year age group and there was a remarkable female predilection. Secondary AIHA was more common (56%) than primary. SLE was identified as the most common underlying disorder in secondary AIHA. Majority (46%) were Grade 4 DAT positive. Predominant autoantibody identified was IgG (52%). Of the total IgG positive cases, IgG1 was the predominant subclass. C3d alone was detected in 18% of cases and C3d and IgG together in 30%. About 48% of our patients were of warm type, 32% mixed type, and 20% cold type. About 80% of the study population were treated with steroids alone. A small percentage of cases (16%) needed immunosuppressant in addition to steroids and still a smaller percentage (4%) needed splenectomy. Higher grades of DAT positivity were associated with more severe degree of anemia and hyperbilirubinemia. The study also demonstrated a positive correlation between DAT grade and severity of hemolysis. Conclusion: AIHA patients in this study were predominantly of Warm AIHA with more of IgG1 involvement. A significant association is found between higher grades of DAT results and severity of anemia and jaundice in this study group. A positive correlation exists between grades of DCT and hemolysis as well.

The clinical value of serum bilirubin, hemoglobin, and reticulocyte combined with immunohematological tests in the diagnosis of ABO neonatal hemolytic disease

The clinical value of serum bilirubin, hemoglobin, and reticulocyte combined with immunohematological tests in the diagnosis of ABO neonatal hemolytic disease

Immunohematology Red Cell Serology Testing Reference Laboratory

Immunohematology reference laboratory (IRL) is defined as a fully equipped advanced laboratory that receives samples from various parts of the country for workup. This is a specialized center, where other centers experiencing difficulty in resolving immunohematological tests, refer samples for further workup and resolution. To complete the workup process, ABO RhD typing, antibody screening, identification (ID), antigen phenotyping, and direct antiglobulin tests are performed. In our retrospective observational study 528 cases, worked up from October 2019 to March 2022 were included. The prevalence of alloimmunization found in this evaluation was 68.1%. Among the different alloantibodies, anti-D was most common followed by anti-E and anti-M. In our study, most of the autoantibodies were of Immunoglobulin G (IgG) class (79.31%). Out of the 528 samples, ABO discrepancy was found in 48 samples (9%). Of these, none belonged to Group I or Group III discrepancy types. Group II discrepancies were noted in 28 cases (58.3%) and Group IV discrepancies were found in 20 cases (41.6%). Our study clearly indicates that there is an important role of IRL which is not only limited to ID of alloantibodies or resolution of ABO discrepancies but also supports all the hospitals and transfusion centers in the region by providing phenotype-matched or compatible units and advice for safe transfusion practices.

Prevalence of Alloimmunizations in Moroccan Pregnant Women

Introduction: Erythrocyte fetomaternal incompatibility is defined by the binding of erythrocyte alloantibodies of a pregnant woman to fetal antigens, inherited from the father. Alloantibodies are produced by the immune system after prior contact with these same antigens during transfusion, transplant or previous pregnancy. In Morocco, data concerning fetomaternal incompatibilities are insufficient despite the severe cases of hemolytic disease in newborns recorded. Our aim is to determine the prevalence of anti-erythrocytes alloimmunizations in Moroccan pregnant women as well as the frequencies of alloantibody specificities. Patients and Methods: A population of parturients with no obstetrical history was randomly recruited to the Blood Bank of Kenitra. A second population was formed by pregnant women referred to the Regional Blood Transfusion Center of Rabat for reasons of obstetrical and/or immunohaematological history. The tests were carried out using the gel cards and 2 panels of 11 red blood cells. Antibody titration was performed by indirect Coombs technique. Results: Immunohematological tests and analysis of clinical-biological data made it possible to detect and confirm alloimmunization in 16 RhD negative and positive women. The prevalence of alloimmunization in RhD negative women is 2.46 % and the prevalence of alloimmunization in both RhD-/+ parturients was 1,06 %. In parturients with an obstetric history, the frequencies of alloantibodies are respectively 35.48% (11/31) and 100% (3/3) directed against 7 antigenic specificities: D, C, E, c, e, Jka and s. None of the parturients had received timely anti-D prophylaxis or prenatal RhD genotyping. Conclusion: The discussion of our results highlights the problem of the management of pregnant women at risk of alloimmunization, putting Morocco in front of a challenge of setting up a health policy, including above all the training of health professionals and the accessibility at the national level to the biological examinations necessary for the follow-up of the pregnant women to reduce the prevalence of the HDFN.

Preservation of red blood cell antigenicity in a new storage solution in vitro

Introduction Red blood cell (RBC) storage solution is used for suspending and preserving RBCs for later use in in vitro immunohematology testing. Proper RBC preservation is crucial for obtaining accurate results in RBC phenotyping and pretransfusion antibody screening tests. Haemolysis or RBC antigen degradation during storage can result in inaccurate RBC phenotyping, thereby decreasing the sensitivity of pretransfusion antibody screening and identification assays. The conventional RBC storage solutions usually contain adenosine, adenine, and antibiotics. We designed an RBC storage solution and determined whether it could preserve RBC integrity for 70 days. Materials and Methods The new storage solution has a different formula from that of the conventional solution—in particular, it is strengthened with polyethylene glycol (PEG). The extent of haemolysis and hemagglutination reactivity of the RBC antigen systems, Rh, Duffy, Kidd, Lewis, MNS, P1, and the rare antigen Mia (which has a low prevalence antigen in most parts of the world but a higher prevalence in Taiwan), in the new RBC storage solution was compared with that of the conventionally preserved RBC storage solution. Results The RBCs preserved in the new solution for 70 days retained a similar haemolysis grade as those preserved in the control solution for 28 days. Although both solutions largely preserved RBC antigenicity, the decline in RBC hemagglutination scores in new solution often occurred later than that in the control solution in most antigen phenotyping assays, especially labile antigens such as D, P1, and M. Conclusion The new solution reduces haemolysis more effectively and preserves antigenicity throughout the 70-day storage period. Moreover, Mia antigen is more stable in the experimental group.

A Retrospective Audit of Red Cell Serology Requisition Forms Received at a Reference Testing Center for Work-Up

Background and Objectives: Audits identify areas of problems in immunohematology workup and transfusion practice which can be corrected by the education of medical staff, formulation of guidelines, and algorithms. An audit is a series of simple, direct questions, which when answered and reviewed, tell us whether the laboratory is performing its procedures, activities, and policies correctly. The aim of this study was to analyze immunohematology request forms sent from red cell serology laboratories to our reference testing center (RTC) to ascertain their completeness. Materials and Methods: This was a retrospective, observational study conducted in the department of transfusion medicine at a tertiary-level health-care center from November 2019 to June 2021. We ascertained whether the immunohematology workup forms details were complete, absent, or incomplete. Results: The study was conducted over a period of 20 months, with 264 forms being audited. In this overall total number, almost one-third of 1894 (34.16%) of the immunohematology workup requisition form details were complete and 716 (12.91%) of these entries were incomplete. However, almost half of the overall number of 2934 (52.92%) of the requisitions were absent. Conclusion: From our study, we concluded that an audit of all the RTC requisitions at the point of receiving can be an important tool to detect requisition errors and results of RTC workup. We received a sample for RTC advanced immunohematological testing from all over India. There is a need for the organization of CME and training of staff to increase compliance regarding sending appropriate RTC advanced immunohematological requisitions and samples.