# I. Material & Methods total of 378 patients and 2050 donors were included in this study period of two years (July 2016 to June 2018) in the Department of Pathology, St. Stephens Hospital, New Delhi, India. All the hospital population (patients as well as donors) blood samples were included in the study. The antibody screening tests performed were Indirect Coomb's tests, Direct Coomb's tests and Auto control. The method of screening used was gel card technology. # II. Statistical Analysis Qualitative variables are expressed as frequencies / percentages and compared between groups using Chi-square / Fisher's Exact Test. Quantitative variables are written regarding mean ± sd and compared using Unpaired t-test / Mann-Whitney Test. A p-value < 0.05 is considered statistically significant. The data is tabulated in MS Excel and analysis performed using Statistical Package for Social Sciences (SPSS) version 16.0 software. # a) Study Design # Cross-sectional study b) Sample Size Determination The formula used for sample size estimation was d 2 n=Z? 2 P(1-P) # III. Result and Discussion Our study included 378 patients and 2050 donors. The age of patients ranged from new born to 80 years with a mean age of 28.64 years. The maximum Author ? ? ? ? ¥: DNB, Junior Resident and Department of Pathology, St. Stephen's Hospital, Delhi. e-mails: jagritiyadav91@gmail.com, richa_jindal2003@yahoo.com, hemagoyal88@gmail.com, kuldeep_0787@yahoo.com, mollymaria54@yahoo.co.in number of cases were in the age group of 21-30 years (58.20 %), followed by 31-40 years (19.84 %) and two cases were in the age group of 71-80 years (0.53 %). Female predominance was seen with a male to female ratio of 1:5.6. The most common causative factors in our study were the previous history of transfusion, females presented with pregnancy either primigravida or multigravida and Rh-negative blood group. Blood group B was the most frequent blood group followed by blood group O. The present study has an alloimmunization rate of 3.44% which is comparable to all the other studies mentioned above. A study by Nikam et al. 7 had least alloimmunization rate of 0.74 %. Choudhary et al. had the highest alloimmunization rate of 9.8%. 3 The percentage of alloimmunization in all the abovementioned studies fall somewhere between <1% to 10%. According to published data rates of alloimmunization in random patients vary from 0 to 3 observational studies in random patients, who most often receive an incidental transfusion, and pregnant women estimated the prevalence between <1-3%. 12 This incidence increases in multi-transfused patients and transfusion-dependent patients. The reported prevalence of alloimmunization in multi-transfused patients in India is comparatively low varying from approximately 3% to 10%. 3,9,13 # a) Analysis of Autocontrol in Patients Out of 378 cases, two patients showed auto control positivity. Out of 378 patients, AC was positive only in two patients, and those were females (0.53%). Among those two patients, one was Rh-positive and the another one was Rh-negative. History of previous transfusion (1.7%) is the most common cause of auto antibodies followed by pregnancy (0.43%). Similarly, in our study, one patient had history of transfusion and other was a pregnant female had auto control positive rate. It was observed in our study that antibodies are more commonly found in the age group between 20-40 years. There is a paucity of literature on the detection of antibodies by auto control. In our study, only ten donors had antibodies in their blood (0.49%). Makroo RN et al. drawn similar results in his study in which out of 82153 donors 227(0.27%) had antibodies in their blood. 17 The study by Pahuja S et al. had a total of 7756 donors out of which 4(0.05%) donors had antibodies in their blood. 16 Garg N et al. had a similar result of 0.09% antibodies in 47450 donors. 18 The blood with antibodies were discarded and not transfused to patients. # IV. Conclusion Clinically significant antibodies were frequently detected in our patients and donors population. Alloimmunization in Rh D positive women was low as compared to Rh D negative women. The previous history of transfusion was an important cause for the development of antibodies. Males were more than females in donor population showed that males are more active in donating the blood. We recommended that ? Antibody screening must be done both in patients and donors to find the irregular antibodies. ? Antibody screening should be done in pregnant females to prevent Rh incompatibility or HDFN. ? Antibody screening should be done in donors to detect the presence of alloantibodies and is an important to provide compatible blood products and to avoid transfusion reactions. ? Multi-transfused patients have a high probability of developing alloantibodies, so extended screening is recommended in the patients to prevent hemolytic transfusion reactions. 1Year 20183Total Patients n = 378 Gender Distribution Gender n Male 57 Female 321 Total 378 Age Group (Years) Age (Years) n% 15.08% 84.92% 100% %Volume XVIII Issue II Version I? 10 11 -2029 167.67% 4.23%( D D D D )21 -30 31 -40 41 -50 51 -60 61 -70 71 -80 Total220 75 14 13 9 2 37858.20% 19.84% 3.70% 3.44% 2.38% 0.53% 100%Medical ResearchMean ± sd ABO Blood Group 28.64 Blood Group n A 88 B 138 AB 42±12.13 % 23.28% 36.51% 11.11%Global Journal ofO11029.10%Total378100%Rh D DistributionRh D Positive35293.12%Rh D Negative266.88%In our study ICT was positive in patients with mean age of 30.24 years, whereas DCT was positive in patients with mean age of 37.04 years and AC was positive with a mean age of 30.59 years.A 2AuthorYearTotal PatientsAll Immunised Patients (ICT Positive Cases)The Rate of Alloimmunization (%)Sirchia et al. 119851432745.2Chow et al. 21994436266Choudhary et al. 319998189.8Ansari et al. 420078033.75Roopam et al. 520099655.21Pahuja et al. 6201021183.79Nikam et al. 720117410.74Usman et al. 82011800303.75Sood et al. 92013306134.24Makroo RN et al. 10201449,0774030.82Present study2018378133.44 3AuthorYearTotal PatientsAll Immunised Patients (DCT Positive Cases)The Rate of Alloimmunization (%)Nakamura Y et al. 141984421143.3Pahuja S et al. 62010211-0.47Valsami S et al. 1520152695702.59Present study2018378154.23DCT is the cornerstone of the diagnosis ofhemolytic disease of the newborn (HDN). In our study,out of 378 patients, DCT was positive in 16 patients. Thepositivity rate of DCT in our study was 4.23%. Pahuja Set al. drawn similar results by DCT and had a 0.47% rateof immunization. 6 4StudyYearTotal DonersAll Immunised Doners (ICT Positive)The Rate of Alloimmunization (%)Pahuja S et al. 162013775640.05Garg N et al. 18201447450460.09Makroo RN et al. 172018821532270.27Present study20182050100.49 Analysis of RBC Antibody Screening in a Hospital Population Over a Two Years Period * Red cell alloantibodies in thalassemia major GSirchia AZanella AParravicini PRebulla FMorelati GMasera Transfusion 25 2 1985 Mar 4 * Red cells, HLA and platelet antibody formation in patients with multiple transfusions MPChow HYHu JYLyou JSLin CHYung ALee TDLee Actahaematologica 92 2 1994 * Red cell alloimmunization in multi-transfused chronic renal failure patients undergoing hemodialysis JSShukla RKChaudhary Indian J Pathol Microbiol 42 1999 * Assessment of frequency of alloimmunization and erythrocyte autoimmunization in transfusion dependent thalassemia patients SAnsari PVMoshtaghian Acta MedicaIranica 46 2 2008 * A prospective study for detection and identification of red cell alloantibodies in multiply transfused thalassemia major patients: 34 th National Congress of Indian Society of Blood Transfusion and Immune Haematol JRoopam JPerkins JTSusan NAChoudhury 2009 * Alloimmunization and red cell autoimmunization in multi-transfused thalassemics of Indian origin SPahuja MPujani SKGupta JChandra MJain Hematology 3 2010 Jun 1 * Prevalence of red cell allo-immunization in repeatedly transfused patients with B-thalassemia in SANikam SBDama SASaraf CJJawale RVKirdak RPChondekar Organized by Department of Zoology, D.B.F. 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