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.

Neonatal screening of ABO/RhD blood group and direct antiglobulin Coombs test. Experience of a single institution.

BACKGROUND: Evaluating the ABO/RhD blood group and the direct antiglobulin Coombs test (DAT) at birth is recommended good practice, but there is variability in its universal implementation. This study aims to show the comparative results in various variables of clinical impact during the hospital stay of neonates with positive DAT compared with those with negative DAT, based on the systematic detection of the ABO/RhD group and DAT at birth. METHODS: Newborns between 2017 and 2020 in a high-risk pregnancy care hospital were included. The ABO/RhD and DAT group was determined in umbilical cord samples or the first 24 hours of life. Demographic, maternal, and neonatal variables were recorded. The association between the variables was estimated using the odds ratio (OR). RESULTS: 8721 pairs were included. The DAT was positive in 239 newborns (2.7%), with the variables associated with positive PDC being maternal age > 40 years (OR: 1.5; 95% CI: 1.0 to 2.3), birth by cesarean section (1.4; 1.1-2.0), mother group O (6.4; 3.8-11.8), prematurity (3.6; 2.6-5.0), birth weight < 2500 g (2.1; 1.6-2.8), newborn group A (15.7; 10.7-23.1) and group B (17.6; 11.4-27.2), hemoglobin at birth < 13.5 g/dl (4.5; 2.8-7.1) and reticulocytosis > 9% (1.9; 1.2 to 3.1). DISCUSSION: The frequency of neonatal positive PDC was 2.7%, with a significant association with maternal/neonatal incompatibility to the ABO and RhD group, with a substantial impact on various neonatal variables. These results support the policy of universal implementation at the birth of the ABO/RhD and DAT determination.

INTRODUCCIÓN: La determinación del grupo sanguíneo ABO/RhD y la prueba directa de Coombs (PDC) al nacimiento son una práctica recomendada, pero existe variabilidad en su implementación universal. Se presentan los resultados de la determinación al nacimiento del grupo ABO/RhD y la PDC en una cohorte institucional. MÉTODOS: Se incluyeron los recién nacidos entre 2017 y 2020 en un hospital de atención a embarazos de alto riesgo. Se determinó el grupo ABO/RhD y se realizó la PDC en muestras de cordón umbilical o en las primeras 24 horas de vida. Se registraron las variables demográficas, maternas y neonatales. Se estimó la asociación entre las variables mediante la razón de probabilidad (OR). RESULTADOS: Se incluyeron 8721 binomios. La PDC fue positiva en 239 recién nacidos (2.7%), siendo las variables asociadas a la PDC positiva la edad materna > 40 años (OR: 1.5;IC95%: 1.0-2.3), el nacimiento por vía cesárea (1.4; 1.1-2.0), la madre del grupo O (6.4; 3.8-11.8), la prematuridad (3.6; 2.6-5.0); el peso al nacer < 2500 g (2.1; 1.6-2.8); el neonato del grupo A (15.7; 10.7-23.1) o del grupo B (17.6; 11.4-27.2), la hemoglobina al nacer < 13.5 g/dl (4.5; 2.8-7.1) y la reticulocitosis > 9% (1.9; 1.2 a 3.1). DISCUSIÓN: La frecuencia de PDC positiva neonatal es del 2.7%, con asociación significativa la incompatibilidad materna/neonatal al grupo ABO y RhD, con impacto significativo en diversas variables neonatales. Estos resultados apoyan la política de implementación universal al nacimiento de la determinación de ABO/RhD y PDC.

Autoimmune Hemolytic Anemias: Classifications, Pathophysiology, Diagnoses and Management.

Autoimmune hemolytic anemias (AIHAs) are conditions involving the production of antibodies against one's own red blood cells (RBCs). These can be primary with unknown cause or secondary (by association with diseases or infections). There are several different categories of AIHAs recognized according to their features in the direct antiglobulin test (DAT). (1) Warm-antibody AIHA (wAIHA) exhibits a pan-reactive IgG autoantibody recognizing a portion of band 3 (wherein the DAT may be positive with IgG, C3d or both). Treatment involves glucocorticoids and steroid-sparing agents and may consider IVIG or monoclonal antibodies to CD20, CD38 or C1q. (2) Cold-antibody AIHA due to IgMs range from cold agglutinin syndrome (CAS) to cold agglutin disease (CAD). These are typically specific to the Ii blood group system, with the former (CAS) being polyclonal and the latter (CAD) being a more severe and monoclonal entity. The DAT in either case is positive only with C3d. Foundationally, the patient is kept warm, though treatment for significant complement-related outcomes may, therefore, capitalize on monoclonal options against C1q or C5. (3) Mixed AIHA, also called combined cold and warm AIHA, has a DAT positive for both IgG and C3d, with treatment approaches inclusive of those appropriate for wAIHA and cold AIHA. (4) Paroxysmal cold hemoglobinuria (PCH), also termed Donath-Landsteiner test-positive AIHA, has a DAT positive only for C3d, driven upstream by a biphasic cold-reactive IgG antibody recruiting complement. Although usually self-remitting, management may consider monoclonal antibodies to C1q or C5. (5) Direct antiglobulin test-negative AIHA (DAT-neg AIHA), due to IgG antibody below detection thresholds in the DAT, or by non-detected IgM or IgA antibodies, is managed as wAIHA. (6) Drug-induced immune hemolytic anemia (DIIHA) appears as wAIHA with DAT IgG and/or C3d. Some cases may resolve after ceasing the instigating drug. (7) Passenger lymphocyte syndrome, found after transplantation, is caused by B-cells transferred from an antigen-negative donor whose antibodies react with a recipient who produces antigen-positive RBCs. This comprehensive review will discuss in detail each of these AIHAs and provide information on diagnosis, pathophysiology and treatment modalities.

Clinical profile and serological correlation with haemolysis in DAT-positive autoimmune haemolytic anaemia patients in Bangladesh.

Discerning the type of autoimmune haemolytic anaemia (AIHA) is crucial for transfusion support and initiation of treatment. This study aimed to establish the clinical profile and serological character of red cell autoantibodies and to investigate the relationship with haemolysis in AIHA patients who were direct antiglobulin test (DAT)-positive. A total of 59 DAT-positive AIHA patients were included in this study. Clinical, laboratory and serological findings were evaluated to find the gradation of haemolysis and to investigate its correlation with age, sex, type of autoantibody and level of autoantibody. Study findings revealed that most patients (89.8%) had haemolysis, wherein moderate haemolysis (67.8%) was predominant. Weakness, palpitations, fever, pallor, tachycardia and splenomegaly were common among patients with severe and moderate haemolysis. The majority (66.1%) had an associated disorder. Warm autoantibody was the most common, followed by cold and mixed cases. The severity of haemolysis correlated strongly with the strength of the DAT reaction (Cramer V 0.636, p<0.001). These findings may be useful to clinicians while determining a treatment plan. The direct relationship between severity of haemolysis and strength of DAT needs further exploration in a large population to establish whether it can be used as a tool to formulate a treatment plan when assessing AIHA patients in low resourced countries.

Challenging the dogma: Red blood cell-directed autoimmunity as risk factor for red blood cell alloimmunisation after blood transfusion.

Red blood cell autoimmunity and alloimmunity are potentially linked. Quantification of this association can tailor extensively matched red blood cell transfusions in patients with autoimmunity. Using an incident new-user cohort comprising 47 285 previously non-transfused, non-alloimmunised patients, we compared transfusion-induced red blood cell alloimmunisation incidences in direct antiglobulin test (DAT)-positive and control patients. Additionally, we performed case-control analyses to handle potential confounding by clinical immunomodulators. Among (IgG and/or C3d) DAT-positive patients (N = 380), cumulative red blood cell alloimmunisation incidences after 10 units transfused reached 4.5% (95% confidence interval [CI] 2.5-8.2) versus 4.2% (CI 3.9-4.5, p = 0.88) in controls. In case-control analyses, alloimmunisation relative risks among DAT-positive patients increased to 1.7 (CI 1.1-2.8). Additional adjustments for pre-DAT transfusion exposure or the extent of Rh/K mismatching did not impact results. In conclusion, while patients with DAT positivity show an intrinsically increased alloimmune red blood cell response, their absolute risk is comparable to control patients due to counteracting co-existing immunosuppressive conditions. Consequently, isolated DAT positivity in patients lacking overt haemolysis or complicated alloantibody testing does not seem to warrant extended matching strategies.

Alectinib-induced Hemolytic Anemia with Positive Direct Antiglobulin Test in a Patient with Lung Adenocarcinoma: A Possible Drug-drug Interaction Effect.

Recent studies have reported that direct antiglobulin test (DAT) results were negative in cases of alectinib-induced hemolytic anemia with abnormal red blood cell (RBC) morphology. We herein report the case of a 72-year-old female patient who was diagnosed with alectinib-induced hemolytic anemia who - in contrast to previous reports - showed a positive DAT result. After discontinuing famotidine and alectinib, the DAT results turned negative; however, when alectinib was resumed, hemolysis recurred. Although alectinib-induced hemolytic anemia has been previously thought to be associated with abnormal morphological changes of the RBCs, we suggest that alectinib-induced anemia may manifest as DAT-positive immune hemolytic anemia because of a complementary effect with other drugs.

Neonatal hemolytic disease: How should we use indirect and direct antiglobulin tests?

BACKGROUND: In newborns with hemolysis, the direct antiglobulin test (DAT) and indirect antiglobulin test (IAT) play a key role in demonstrating the presence of an immune cause. We aimed to emphasize the importance of IAT in mothers of DAT-positive babies. METHODS: DAT was performed with forward blood grouping on cord blood in term babies who were born between September 2020 and September 2022. IAT was performed in the mothers of the babies who were found to have a positive DAT and antibody identification was performed in the mothers who were found to have a positive IAT. Specific antibodies detected and identified were associated with the clinical course. RESULTS: The study included 2769 babies and their mothers. The prevalence of DAT positivity was found to be 3.3% (87 of 2661). In DAT-positive babies, the rate of ABO incompatibility was 45.9%, the rate of RhD incompatibility was 5.7% and the rate of RhD and ABO incompatibility in association was 10.3%. The rate of subgroup incompatibility and other red blood cell antibodies was 18.3%. Phototherapy was applied because of indirect hyperbilirubinemia in 16.6% of the DAT-negative babies and in 51.5% of the DAT-positive babies. The need for phototherapy was significantly higher in DAT-positive infants (p < 0.01). Severe hemolytic disease of the newborn, bilirubin level, duration of phototherapy and use of intravenous immunoglobulin were found to be significantly higher in the babies whose mothers were IAT positive compared with the babies whose mothers were IAT negative (p < 0.01). CONCLUSIONS: IAT should be performed on all pregnant women. When screening with IAT is not performed during pregnancy, performing DAT in the baby plays a key role. We showed that the clinical course was more severe when mothers of DAT-positive babies were IAT positive.

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.

BACKGROUND: Hemolytic 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.

Does strengths of a positive direct antiglobulin test predicts the need for phototherapy and duration of phototherapy? - a single center, retrospective study.

BACKGROUND: Use of Direct Antiglobulin test (DAT) in management of neonatal hyperbilirubinemia is conflicting. OBJECTIVE: whether strength of positive DAT predicts the need for phototherapy, duration of phototherapy and need for major interventions. METHODS: We retrospectively collected data on all DAT positive neonates with birth gestational age ≥32 weeks over six years (2014-2019). Data regarding blood group, DAT and clinical details were obtained from a hospital database. We also collected data on serial hemoglobin and other relevant laboratory parameters. We also collected data on infants receiving major interventions such as exchange transfusion, in-utero transfusion, immunoglobulins, and postnatal transfusion for the duration of the study period. All of these infants were electronically followed up for a period of 6 weeks. This study was approved by institutional audit authority. All the statistics were performed using SPSS software. RESULTS: Out of 1285 DAT tests performed, only 91 infants were positive (7%), and 78 DAT positive infants were available for analysis. There were 54 infants with DAT (1+), 15 infants with DAT (2+), 7 infants with DAT (3+) and 2 infants with DAT (4+). There was no significant statistical difference in terms of need for phototherapy, duration of phototherapy, need for major interventions and hemoglobin levels at different time points between the groups (DAT 1+ Vs DAT ≥2+; DAT ≤2+ Vs DAT >2). A Total of 10 infants received major intervention, with one infant receiving all three interventions (DAT 3+ with significant maternal antibodies), 2 additional infants (both DAT1+) received exchange transfusion, 6 additional infants received immunoglobulin (2 infants: DAT 2+; 4 infants: DAT 1+) and one additional infant (DAT 1+) with significant maternal antibodies received a postnatal transfusion. CONCLUSION: Strength of a DAT did not predict the need for phototherapy, duration of phototherapy, and the need for major hemolysis related intervention in the first 6 weeks of life.

Comparison of automated solid phase versus manual saline indirect antiglobulin test methodology for non-ABO antibody titration: Implications for perinatal antibody monitoring.

BACKGROUND: Accurate antibody titration is crucial in prenatal evaluations to identify patients who need clinical monitoring for hemolytic disease of the fetus and newborn (HDFN) causing fetal anemia. This study compares the established gold standard method of manual tube saline indirect antiglobulin testing (SIAT) with the newer automated solid phase (ASP) method of antibody titration and aims to establish the critical titer threshold for ASP that corresponds to the previously established SIAT critical threshold of ≥16 used in our laboratory. STUDY DESIGN AND METHODS: One hundred fifty-seven prenatal and donor plasma samples with known antibodies were tested using both SIAT and ASP methodologies and results were compared. RESULTS: The study found that ASP titers were, on average, 1.33 dilutions higher than SIAT titers. The critical titer cutoff for ASP was determined to be ≥32, which is one tube higher than the SIAT cutoff of ≥16. DISCUSSION: The ASP method for antibody titration offers greater reproducibility and efficiency compared with manual SIAT titration. This study suggests that a titer cutoff of ≥32 is appropriate for most clinically significant antibodies using ASP. However, further research is needed to determine the comparability of ASP with SIAT in samples with multiple antibodies, anti-M antibodies, and other less common antibodies. Validation of the ASP titer cutoff against HDFN clinical outcomes is required before implementing this test for routine use in perinatal antibody titration.

Favorable outcome without corticosteroids during post-artesunate delayed hemolysis with positive direct antiglobulin test in severe imported Plasmodium falciparum malaria, France.

OBJECTIVES: Positive direct antiglobulin tests (DATs) have been reported in cases of post-artesunate delayed hemolysis (PADH), but the causal role of auto-immune hemolysis remains unclear. We aimed to analyze a cohort of patients with PADH and DAT during severe malaria. METHODS: We describe PADH and DAT results in a 7-year multi-center retrospective cohort of patients receiving artesunate for severe imported malaria. RESULTS: Of 337 patients treated with artesunate, 46 (13.6%) had at least one DAT result within 30 days of treatment initiation, and 25/46 (54.3%) had at least one positive DAT. Among 40 patients with available data, 17 (42.5%) experienced PADH. Patient characteristics were similar for patients with a positive or negative DAT, and DAT positivity was not associated with PADH occurrence (P = 0.36). Among patients, 5/13 (38.5%) with a positive DAT after day 7 experienced PADH, compared to 10/13 (76.9%) of those with a negative DAT after day 7 (P = 0.11). Overall, 41% of patients required blood transfusions, and outcome was favorable without corticosteroids, even in cases of PADH. CONCLUSIONS: DAT does not appear to be a marker of PADH, but rather an indirect marker of an immune-mediated mechanism. DAT positivity should not lead to the administration of systemic corticosteroids during PADH.

Hematologic Abnormalities After COVID-19 Infection: A Case of Coombs-Negative Hemolytic Anemia and Thrombocytopenia.

The occurrence of hemolytic anemia in patients with active SARS-CoV-2 infection has been documented in medical literature. While relatively uncommon, there have been instances where this condition presents as a Coombs-negative hemolytic anemia. In this research study, we report a distinctive case of Coombs-negative hemolytic anemia and thrombocytopenia in a patient with a known history of COVID-19 infection. The patient demonstrated a favorable response to treatment involving the administration of steroids and intravenous immunoglobulin (IVIG) therapy. This case adds to the existing body of evidence regarding the hematological manifestations of SARS-CoV-2 infection, highlighting the importance of considering and managing hematological complications in patients with COVID-19.

Erythrophagocytosis in autoimmune immunoglobulin A-mediated hemolysis.

INTRODUCTION: Warm antibody-mediated autoimmune hemolysis (WAIHA) is most often due to immunoglobulin G (IgG) antibodies and is detected by direct antiglobulin test (DAT). However, about 10% cases of hemolytic anemia are DAT negative. Herein, we describe a patient with DAT-negative hemolytic anemia due to an anti-IgA antibody. We investigate if isolated IgA can promote erythrophagocytosis. METHODS: We isolated patient and control IgA on Jacalin agarose. Isolated IgA was used to sensitize healthy ABO/Rh-matched donor red blood cells (RBC). Antibody binding was examined by flowcytometry. The effect of IgA on erythrophagocytosis was evaluated using Macrophage colony stimulating factor 1 (M-CSF)-differentiated autologous macrophages by Giemsa staining and immunofluorescence microscopy. RESULTS: We show that isolated IgA from the serum can bind to red cells. In addition, RBCs were phagocytosed efficiently by autologous macrophages in the presence of patient IgA. CONCLUSION: Our results show that IgA antibodies are capable of inducing erythrophagocytosis like IgG antibodies in the absence of complement fixation.

The enhanced direct antiglobulin test in current practice has a limited impact on management of adult patients.

INTRODUCTION: The direct antiglobulin test (DAT) identifies immunoglobulin IgG and/or complement onthe red blood cell surface, allowing discrimination between immune and non-immunehemolysis. When the DAT is negative but there is clinical suspicion for immunehemolysis, an enhanced DAT can be sent to an immunohematology referencelaboratory (IRL). METHODOLOGY: This retrospective study assessed the volume of enhanced DATs at a large tertiarycare center and evaluated their impact on patient care. Enhanced DATs were sent on21 adult patients (January 2019 - January 2021) at the University of Pittsburgh MedicalCenter and Allegheny Health Network. Laboratory and clinical data were collected andanalyzed. RESULTS: Four out of 21 patients had positive tests (DAT and other serologic tests) at the localIRL. Enhanced DAT testing yielded positive results in an additional 5 patients butnegative or invalid results for 2 patients. High-dose steroid therapy was started in 12patients prior to receipt of enhanced DAT results. Enhanced DAT testing was sent amedian of 5 days after initiation of steroid therapy. For the patients trialed on steroids,the enhanced DAT results impacted medical decision-making in only 3 patients, and inonly one of those patients was the enhanced DAT positive despite a negative DAT at alocal IRL. In the non-steroid treated patients, enhanced DAT results did not contributeto clinical decision-making. CONCLUSION: Enhanced DATs generally did not impact medical decision-making in adults withhemolytic anemia.

Polyagglutinability phenomenon: a case report and review of the literature.

BACKGROUND: Polyagglutinability of red blood cells is a rare immunological phenomenon, it is due to a cryptic antigen that is abnormally present on the surface of red blood cells. The aim of our work is to shed light on polyagglutinability, which is still poorly understood cause of discordance between the cell and serum tests and can sometimes have harmful transfusion consequences. CASE PRESENTATION: We report the case of a 70-year-old African patient admitted for management of hemolytic anemia. RESULTS: During the erythrocyte grouping, a discordance between the cell and serum tests was observed, with polyagglutinability for the RH phenotype, a positive AB control, and even a positive control. The direct antiglobulin test and the Coombs test were also positive. The same results were obtained even after washing the red blood cells and incubating them at 37 °C for 30 min. For transfusion purposes, erythrocyte genotyping was performed, and the patient was transfused with an A+ red blood cell unit with an RH Kell-compatible phenotype. CONCLUSION: Polyagglutinability should always be taken into account when grouping anomalies are encountered. Although it may not show any symptoms, hemolysis is frequently observed during transfusions.

[In macrohematuria, medication history also needs to be considered : Penicillin-induced immune hemolysis: a case report and review of literature]. / Bei Makrohämaturie auch an Medikamentenanamnese denken : Penicillininduzierte Immunhämolyse: ein Fallbericht mit Literaturreview.

BACKGROUND: Drug-mediated immune hemolysis is a rare but potentially life-threatening condition. Based on a case of penicillin-induced immune hemolysis, a structured literature review of case reports and studies on penicillin-mediated Drug-Induced Immune Hemolytic Anemia (DIIHA) was carried out. CASE REPORT: A 28-year-old male patient presented to the emergency department with gross hematuria and non-specific abdominal complaints. The patient had a 10-day history of respiratory infection with bacterial tonsillitis, treated orally with penicillin V on an outpatient basis. Laboratory diagnostics detected pathologically altered direct and indirect hemolysis parameters. After stopping the medication, the patient's condition could be stabilized. CONCLUSION: Diagnosis of penicillin-mediated immune hemolysis requires structured cooperation between clinic and laboratory, as clinical and serological findings may be highly variable with the risk of misdiagnosis. Due to the rarity of the disease, this case report is intended to raise awareness with respect to the triad of abrupt drop in hemoglobin levels in connection with drug therapy and in combination with a strongly positive direct Coombs test.

Immunohematological challenges in COVID infected patients.

BACKGROUND: Several autoimmune disorders have been reported to be related with COVID infection. In continuation to these autoimmune phenomenon, autoimmune hemolytic anaemia (AIHA) also has been noted in COVID infected patients. The aim of the study was to find out the prevalence of red cell alloimmunization, ABO discrepancy and positive direct antiglobulin test (DAT) results in COVID infected patients hospitalised in a tertiary care centre in North India. METHODOLOGY: This was a retrospective observational study done from July 2020 to June 2021. All symptomatic patients admitted to ICU tested positive for SARS CoV-2 whose blood samples were received in the immunohematology laboratory of department of Transfusion Medicine for determination of blood group and issue of packed red cells, and found to have positive antibody screen, blood group discrepancy and positive DAT results, were included in the study. RESULTS: A total of 10,568 tests were run, out of which 4437 were for determination of blood group, 5842 were for antibody screen and 289 were for direct antiglobulin test. Included in this study were 146 patients who either had blood group discrepancy, or had a positive antibody screen or had a positive DAT. Out of 115 positive antibody screen, 66 patients had only alloantibodies, 44 patients had only autoantibodies while only 5 patients had both auto as well as alloantibodies. Total number of positive DAT cases was 50 (50/289 = 17.3 %). There were 26 ABO discrepancies (26/4437 =0.58 %) found. CONCLUSION: Our results also indicate that there is rise in rate of alloimmunization and DAT positivity among COVID patients.