Column Agglutination Technique Research Articles

Frequency of Rh and Kell antigens among blood donors: A retrospective analysis from a tertiary care center in Eastern India

Objectives: The phenotyping of Rh and Kell antigens plays a major role in preventing alloimmunization and adverse events in multi-transfused patients. This study tries to highlight the frequency of Rh and Kell antigens among the blood donors who donated blood at a tertiary care center located in Eastern India. Material and Methods: The study was conducted in the Department of Transfusion Medicine and Blood Bank of All India Institute of Medical Sciences, Patna, from January 2021 to March 2023 on 10,032 whole blood donors of blood groups A, B, O, and AB by column agglutination technique using gel cards for blood grouping and phenotyping. Results: A total of 10,032 whole blood donors of groups A, B, O, and AB were included in the study. The frequency of “D” antigen was 95.77% (n = 9,608), “C” was 90.47% (n = 9,076), “c” was 50.47% (n = 5,063), “E” was 15.9% (n = 1,595), “e” was 99% (n = 9,932), and “K” was 2.67% (n = 268). “c” antigen frequency was 45.81–49.48% in RhD positive blood groups and 100% in all the RhD negative blood groups while “C” antigen frequency was 92.04–94.68% in RhD positive blood groups, and 4–24.13% in RhD negative blood groups. Conclusion: Since pre-transfusion phenotyping in multi-transfusion patients is not routinely practiced, transfusion of at least Rh and Kell phenotyped donor red cells can lead to a great decrease in the risk of alloimmunization and adverse events related to transfusion.

Comparison of Column Agglutination Technique and Tube Test for ABO Antibody Titration and Crossmatching

Comparison of Column Agglutination Technique and Tube Test for ABO Antibody Titration and Crossmatching

I-JAMM-(I): A survey providing an insight into the practices of isoagglutinin titration in ABO incompatible kidney and liver transplantation

Background and objectivesABO-incompatible transplantations allow patients to receive timely transplants. Isoagglutinin titration to ascertain levels of incompatible antibodies in the recipient is important in determining patient selection and transplant survivability. To find out the prevalent trends in India, the largest, first of its kind survey was carried out among the transplant centers regarding their practices in isoagglutinin titration. MethodsThe survey was drafted by a working group of Transfusion and Transplant Immunology specialists from six different centers. Data was obtained via the use of an online questionnaire. ResultsResults were categorized into four categories, Hospital information, Titration methodology, Role of transfusion specialists and cut-off titers. Most centers had a well-established solid-organ transplant program with considerable number of ABO-incompatible transplantations. Most centers performed isoagglutinin titration in Transfusion Medicine department. Column Agglutination Technique (CAT) was the most common method, using EDTA blood samples and freshly-prepared in-house pooled cells. Most centers had a turn-around time of less than 12 h. While the policy for ascertaining baseline and threshold titers is well-defined in ABO-incompatible renal transplants, variations from center to center still exist for ABO-incompatible liver transplants. Most centers required a Transfusion Medicine consultation for the patients before such transplants. ConclusionWith increasing ABO-incompatible kidney and liver transplants across the country, the role of Transfusion medicine specialists has become vital in pre-conditioning regimes enabling the viability and success of such transplants. This was a unique survey that provided a snapshot of current trends and practices of isoagglutinin titration for ABO-incompatible transplants in India.

Molecular analysis and transfusion management in a rare case of cis-AB blood group: A report from India

Molecular characterization of a rare cis-AB blood group has not been done in the Indian subcontinent. Herein, we report a case of A2B3 blood group in an Indian patient which was subsequently confirmed to be a case of cis-AB phenotype. Blood grouping was performed by the column agglutination technique (CAT), conventional tube technique (CTT) and subsequently, whole exome sequencing for molecular analysis. The patient was initially typed as AB, RhD positive in forward grouping. However, serum grouping showed agglutination (2+) with the B red cells in CAT. In CTT, an extra reaction was observed with A1 red cells and a strong agglutination was seen with Anti-H lectin. Thus, the blood group was identified serologically as A2B3. During the next-generation sequencing, a total of 10 exonic variants in the ABO gene were filtered, of which 2 (rs8176747 and rs7853989) were found to be non-synonymous and occurring on the same allele. The other allele was found to be ABO*A1.01. The sample analyzed in the study was found to carry two previously reported nucleotide changes of cis-AB (c.803G > C and c.526C > G) on the same allele which had not been reported before. Transfusion requirement was managed with type O red cells and type AB plasma.

Clinically significant minor blood group antigens amongst South Indian donor population

Background and objectives: Distribution of blood group antigen varies among different races. It is important to know the distribution of these antigens so as to provide a donor database that aid in providing compatible blood units for patients with multiple alloantibodies. The present study was conducted to determine the distribution of clinically significant minor blood group antigens amongst the South Indian blood donors. Materials and methods: Blood samples were collected from healthy regular repeat voluntary blood donors of same ethnicity attending a tertiary care hospital in South Kerala. Clinically significant blood antigens of the ABO, Rh (D, C, c, E, and e), Kell, Duffy and Kidd blood group systems were determined. The ABO and Rh(D) grouping were performed by tube technique using monoclonal antisera. Column agglutination technique was used to phenotype Rh, Kell, Duffy and Kidd antigens. Results: Total 200 healthy repeat voluntary blood donors were enrolled in the study. Out of 200 donors, 92% were RhD positive. Among the Rh antigens, the e antigen was positive in 97.8 % and 100% among the Rh(D) positive and Rh(D) negative donors respectively. No E antigen was detected in RhD negative donors. Total 6 and 2 Rh phenotypes were observed among the Rh(D) positive and negative donors respectively. R1R1 and Rr were the most frequent phenotypes among the RhD positive and negative donors (47.28% and 93.75%) respectively. Among the Kell blood group antigens, K and Kpb antigens were present in 100% of our donors while in Duffy and Kidd system Fya and Jka were most predominant (89% and 87%) respectively. Conclusions: The findings of the present study would be helpful in developing in-house panel cells. Moreover, a rare donor registry of donors typed negative for a high-frequency antigen can be formulated. IMC J Med Sci. 2024; 18(1):004. DOI: https://doi.org/10.55010/imcjms.18.004 *Correspondence: Soonam John, Department of Transfusion Medicine, Government Medical College, Parippally, Kollam, Kerala,India. Email: johnsoonam@gmail.com

Association of HLA-DRB1 alleles with anti-D alloimmunization in RhD negative pregnant women in India

BackgroundHuman leukocyte antigen (HLA) restriction plays an important role in the susceptibility to alloimmunization against red blood cell (RBC) antigens. The prevalence of anti-D alloimmunization in RhD negative pregnancy is still quite high in our population. Thus, we planned this study to determine the association of HLA-DRB1 alleles with anti-D alloimmunization in RhD negative pregnant women. Material and methodsRBC antibody screen (ABS) was performed for RhD negative pregnant women attending the antenatal clinic our institute. Those with a negative result were included in the ‘non-alloimmunized’ (NAL) group (‘Control’ group), while those with anti-D alloantibody on performing antibody identification were included in the alloimmunized (AL) group of the study (n = 50 each). ABS and identification were done using column agglutination technique. The HLA-DRB1 typing was done by Luminex based reverse sequence specific oligonucleotide probing (SSOP) using commercial kits. The HLA-DRB1 allele frequency was compared in both the groups. ResultsThere was a significant difference between the two groups in terms of gravida (p < 0.001) and history of anti-D immunoprophylaxis (p < 0.001). The frequency of HLA-DRB1*03 and HLA-DRB1*04 alleles was significantly higher in the AL group than the NAL group: 40 % versus 18 % [Odds Ratio (OR): 3.04, 95 % CI: 1.21–7.6; p = 0.015] for HLA-DRB1*03 alleles and 18 % versus 4 % (OR: 5.27, 95 % CI: 1.08–25.78, p = 0.025) for HLA-DRB1*04 alleles. ConclusionThe frequency of HLADRB1*03 and HLADRB1*04 alleles was significantly higher in RhD negative pregnant women alloimmunized with anti-D alloantibody.

Extended blood group phenotyping of donors from the lower and middle Himalayan region of Uttarakhand India: A pilot study.

The state of Uttarakhand, bordering countries such as Tibet and Nepal, is a multi-ethnic region. Further, erythrocyte alloimmunization may arise from the incompatibility of major and/or minor blood groups between ethnically diverse donors and recipients. We aimed to screen Uttarakhand blood donors (UBDs) for extended phenotyping of their erythrocytes serologically. This prospective cross-sectional analysis involved all UBD samples collected at the blood centre of our tertiary-care hospital. Samples were obtained over 9months (Mar'22 to Nov'22). Donors who were O-typed, DAT-negative and non-reactive for TTI markers were processed further for serological testing using the column agglutination technique utilizing 21 different monoclonal antisera (Ortho diagnostics Pvt ltd, Mumbai India). The research was financially aided by UCOST, Uttarakhand, Government of India. Of the 5,407 blood samples collected, the total number of O-typed samples collected was 1622. Of these 1622, 329 (20.2%) O-typed samples were selected based on our inclusion criteria and hence further phenotyped. Amongst these 329 UBDs, the average age was 32.7±9.32 (18-52) years and the male-to-female ratio was (M: F=12:1). The prevalence of high- and low-frequency blood antigens in our study was Rh (D 96.6%, C 84.8%, c 63.5%, E 27.9% and e 92%), Lewis (Lea 6.3%, Leb 31.9%), Kidd (Jka 87.8%, Jkb 63.2%), Kell (K 1.8%, k 96.3%) and Duffy (Fya 63.5%, Fyb 10.6%). And in the MNS system we received 21.2% as M, 10.9% N, 37% S and 51.3% as s respectively. We also identified some very rare minor antigens such as Dia 1.8%, Ina 1.8%, Cw 0.6% and, 1.2% Mur positive donors, which are not common in our population, as per the published literature. Moreover, we also identified one Bombay blood phenotype (Oh) in one of our UBD recruits. To sum up, practically with the outcome of this research, we were also able to identify rare phenotypes among the local people and a rare blood donor registry was created. This repository shall also come in use for our multi-transfused patients having different oncological and haematological ailments.

Prevalence and specificity of red blood cell antibodies in patients transfused in tertiary hospitals in Burkina Faso.

Sub-Saharan African countries face the challenge of immunological transfusion safety that puts many patients at risk of post-transfusion hemolytic reactions. This is because pre-transfusion testing for irregular/unexpected antibodies that helps to prevent these risks are neither universally available nor accessible. The aim of our study was to determine the prevalence of red blood cell alloantibodies and their specificity in patients transfused in Burkina Faso. This was a cross-sectional study including patients who had received at least one blood transfusion. Indirect antiglobulin testing using LISS-enhanced medium gel column agglutination technique was used for antibodies screening and identification. Enzymatic technique with papain-treated red cell reagent was performed in attempt to solve some difficulties if necessary as well as auto-control test and RH-KEL phenotyping when possible to help antibodies identification. A total of 832 patients were included, 51.6% of whom were female, and the median (IQR) age was 34 (20-49) years. Of these, 43.7% had chronic kidney disease and 20.4% were sickle cell patients. The median (IQR) number of immunisation episodes (blood transfusion and pregnancies) was 3 (2-6) with the median (IQR) number of blood units received per patient of 2 (1-5). The proportion of patients with RBCs antibodies was 6.4% (53/832), with mainly anti-Rh antibodies. A combination of 2 antibodies was found in 7 patients and a combination of 3 antibodies in one patient. Antibodies of unknown specificity (AUS) were encountered in 29%. Independent factors associated with antibody positivity were age (OR=1.02; p=0.026), sickle cell disease (OR=3.23; p=0.017) and receiving more than 10 blood units (OR=7.33; p=0.01). In this study, the proportion of patients with RBC antibodies was quite similar to that observed in Sub-Saharan African countries. However, the availability and accessibility of pre-transfusion compatibility tests as well as the quality of methods used should be improved to ensure the safety of blood transfusions.

A prospective observational study to evaluate effect of heat inactivation on ABO titers performed by column agglutination technology and conventional tube technique.

When determining ABO antibody titers, immunoglobulin G (IgG) antibodies can be masked by immunoglobulin M (IgM) antibodies. Hence, the measurement of actual concentration of IgG requires methods like heat inactivation (HI) of plasma. This study was aimed at determining the effects of HI on IgM and IgG titers performed by conventional tube technique (CTT) and column agglutination technique (CAT). This was a prospective, observational study conducted from October 2019 to March 2020. All consecutive A, B, and O group donors who gave consent for participation were included. All samples were consecutively tested by CTT and CAT, before and after HI (pCTT, pCAT). A total of 300 donors were included. IgG titers were found to be more than IgM titers. For group O, IgG titer results were higher for both anti-A and anti-B compared to group A and B. For group A, B, and O, pretreatment results were higher than posttreatment IgG titer results. Median anti-A titers were similar to median anti-B titers across all categories. Median IgM and IgG titers were higher for group O individuals than nongroup O individuals. There was reduction in IgG and IgM titers after HI of plasma. One log reduction in median titers was observed when ABO titers were performed by CAT and CTT. There is one log difference between median antibody titers estimated using heat inactivated and nonheat inactivated plasma. The use of HI for ABO isoagglutinin titer estimation can be considered in low resource settings.

Comparative evaluation of titer estimation of ABO isoagglutinins using three different methods

Background and Aims: While automation has the advantage of objectivity, ease of use, and reproducibility with well-defined end points of agglutination reaction, standardization of these methods has still not been possible. The aim of the present study was to compare results obtained by manual conventional test tube technique (CTT) with semi-automated, column agglutination technique (CAT), and fully automated hemagglutination/solid-phase red cell adherence (HA/SPRCA) by calculating and comparing correlation and median immunoglobulin M (IgM) and immunoglobulin G (IgG) titer. Materials and Methods: This was a prospective, observational study conducted from October 2019 to March 2020. All consecutive A, B, and O group donors who consented to participate were included in the study. All samples were consecutively tested by CTT, CAT, and HA/SPRCA. Results: A total of 300 (100 each from A, B, and O blood groups) donors were included. IgG titers were higher than IgM titers in most group O individuals. This difference was more evident with the use of CAT. The correlation between CTT and CAT was found to be strong, whereas the correlation between CTT and HA/SPRCA was found to be variable for anti-A and anti-B IgG and IgM titers. When measured by CTT and CAT, median anti-A and anti-B titer results for group O individuals were similar. Anti-A and anti-B median titer results obtained by CTT and CAT for group A and B individuals were also similar. Conclusion: Semi-automated method (CAT) shows higher ability in detecting ABO isoagglutinins than the manual method (CTT) and automated method (HA/SPRCA). These methods cannot be used interchangeably.

A prospective observational study to compare abo isoagglutinin titer by conventional test tube and column agglutination technique after heat inactivation of plasma in O blood group individuals

Background and Aims: When determining ABO antibody titers, IgG antibodies can be masked by immunoglobulin M (IgM) antibodies. Hence, the measurement of actual concentration of IgG requires methods such as heat inactivation (HI) of plasma. This study was aimed at determining the effects of HI on IgM and IgG titers performed by conventional test tube (CTT) technique and column agglutination technique (CAT). Materials and Methods: This was a prospective, observational study conducted from October 2018 to March 2020. All consecutive O group donors who gave consent for participation were included in the study. All samples were consecutively tested by CTT and CAT, before and after HI (pCTT and pCAT). Results: A total of 2005 donors were included. IgG titers were found to be more than IgM titers. pCTT IgG results are similar or lower when compared to results obtained by solid-phase red cell adherence (SPRCA), whereas pCAT IgG titers were higher with pCAT when compared to hemagglutination (HA)/SPRCA. The results of titers obtained by pCTT were lower as compared to pCAT and HA/SPRCA, with majority giving results <64. The median IgG and IgM titers for both anti-A and anti-B were highest in pCAT, whereas the median IgG and IgM anti-A and anti-B titers were similar to HA and pCTT. Conclusion: Results obtained by HA/SPRCA were closer to results obtained by pCTT, with the advantage of less time consumption, automation requiring less expertise, and no interobserver variation. Titers obtained by pCAT were higher in comparison to HA/SPRCA and pCTT results, due to high sensitivity.

ANTIGEN FREQUENCY OF KELL, DUFFY, KIDD, MNS AND LUTHERAN BLOOD GROUP SYSTEM IN POPULATION OF NORTH MACEDONIA – TOWARDS RARE BLOOD GROUP REGISTRY

The aim of this study is to perform RBC antigen typing of: Kell, Duffy, Kidd, MNS and Lutheran systems and to calculate antigen and phenotype frequency In 920 blood donors, RBC typing of K, k, Kpa, Kpb, Fya, Fyb, Jka, Jkb, S, s, Lua and Lub antigens was performed using specific monoclonal antisera, antihuman globulin and column agglutination technique with gel cards (BioRad). Antigen and phenotype frequencies were calculated from the statistics module of the donor information system (database for blood donors). The prevalence of Kell antigens is 7.5% for K and 99.94% for k. The phenotype (K+k-) is present in 21 (0.06%) blood donors. The frequency of other clinically significant antigens is as follows: 1.1% (Kpa), 100.0% (Kpb), 60.3% (Jka), 76.2% (Jkb), 65.5% (Fya), 79.5% (Fyb), 59.8% (S), 86.5 (s), 7.2% (Lua) and 92.8% (Lub). The most frequent phenotypes are Jk(a+b+) with 41.5%, Fy(a+b+) with 48.5%, (S+ s+) with 46.3% and Lu(a-b+) with 92.8%. Fy(a-b-) phenotype was detected in 0.21% of blood donors. The estimated RBC antigen frequency in our blood donor population differs from the antigen frequency in different populations. Because of that extended RBC typing is necessary for identifying rare blood group donors within the local population. This strategy enables to meet the needs for RBC transfusion in patients with rare phenotypes and with antibodies against high frequency antigens or multiple antibodies, as well as to prevent RBC alloimmunization in polytransfused patients providing antigen matched RBC.

A Prospective Observational Study to Compare Heat Inactivated ABO Isoagglutinin Titres Performed by CTT and CAT with Solid Phase Red Cell Adhesion (SPRCA) in O Blood Group Individuals

Measurement of actual concentration of IgG requires methods like heat inactivation (HI) of plasma. This study was aimed at comparing of heat treated ABO titers performed by conventional test tube technique (CTT) and column agglutination technique (CAT) with HA/SPRCA.

Production and characterization of a murine anti-dal monoclonal antibody for blood typing in dogs

Considering the strong immunogenicity of the Dal antigen, and that > 98% of dogs, including blood donors, are Dal-positive, finding compatible blood for a previously transfused Dal-negative patient may be challenging. This is exacerbated by limited access to typing reagents, which currently rely on polyclonal antibodies (PAb) produced following sensitization of dogs. Therefore, the objective of this study was to produce and characterize an anti-Dal murine monoclonal antibody (MAb). Conventional hybridoma technology was used to produce MAb directed against canine red blood cells (cRBC). Briefly, female BALB/c mice were immunized via repeated intraperitoneal injections of washed Dal-positive cRBC (DEA 1,3,7 negative; DEA 4,5 positive) until serologic titers were sufficient (>1:1000). Following fusion with myeloma cells, 573 hybridoma cell culture supernatants were obtained and screened for MAb of interest using a gel column agglutination technique and known Dal-negative and Dal-positive cRBC. Fifteen supernatants led to cRBC agglutination, but only one had the desired pattern (i.e. anti-Dal). To assess its specificity and sensitivity, Dal blood typing of 62 canine EDTA-blood samples was performed using the anti-Dal MAb and two canine PAb: 45 Dal-positive and 17 Dal-negative were identified with 100% agreement between reagents (kappa =1). The anti-Dal MAb produced was further determined to be an IgG1. Conventional hybridoma technology, aided by a gel column technique, has enabled the production of a murine MAb specific against the canine Dal antigen. This will ensure long-term perennity of Dal blood typing, facilitate clinical management and research, as well as avoid resorting to repeat dog sensitization.

High Titer Antibodies Demonstrating Prozone in Two Repeat Blood Donors.

- Prozone phenomenon due to excess unbound antibodies may sometimes lead to failure of detection of ABO incompatibility.. The case series describes immunohematology work up of blood group discrepancies of two blood donors. - Blood grouping was performed by a fully automated immune hematology analyzer (FAIHA Diagast, Qwalys 3, France) based on the principle of erythrocyte magnetized technology. Further immunohematology workup was done by tube technique (at different temperatures and phases) and column agglutination technique (CAT). Antibody titration was done by tube technique at saline and AHG (anti human globulin) phase. - Type I blood group discrepancy was detected on initial blood grouping done by an automated analyzer. The discrepancy was resolved by repeat blood grouping by tube technique with a remarkable finding of hemolysis in reverse grouping. The lysis was attributed to high titer antibodies (anti-B titer of 512) with demonstration of prozone phenomenon. However, there was no discrepancy between cell and serum grouping by column agglutination technique (CAT). - Tube technique is the gold standard method for blood grouping and detects blood group discrepancies optimally. Hemolysis which is taken as a positive result, can be best appreciated by tube technique.

Rare Blood Groups in ABO, Rh, Kell Systems - Biological and Clinical Significance.

Background: The frequency of ABO, Rh and Kell blood group antigens differs among populations of different ethnic ancestry. There are low-frequency antigens (<1%) and high-frequency antigens (>90%). A rare blood group is defined as the absence of a high-frequency antigen in the general population, as well as absence of multiple frequent antigens within a single or multiple blood group systems. Aim: To perform red blood cell typing and to calculate the antigen and phenotype frequencies, in order to identify rare blood group donors within the clinically most important АВО, Rh and Kell systems. Material and Methods: АВО, Rh (D, C, E, c, e) and Kell (K) antigen typing was performed using specific monoclonal sera and microplate technique, while Cellano (k) typing was performed with a monoclonal anti-k, antihuman globulin and column agglutination technique. Weak ABO subgroups were determined using the absorption elution method or molecular genotyping (PCR-SSP). Results: ABO antigen frequency is: A (40.89%), O (34.22%), B (16.97%), AB (7.92%) and weak ABO subgroups (0, 009 %). The established genotypes were AxO1 (0, 0026%) and AxB (0, 001%). Rh antigen frequency is: D (85.79%), C (71.7%), c (76.0%), E (26.0%) and е (97.95%). The most common Rh pheno-type is the DCcee (32.7%) while the rarest phenotype is the DCCEE phenotype (0. 003%). The prevalence of K and k antigen is 7.5% and 99.94%, respectively. The frequency of the rare phenotype K+k- is 0.06%. Conclusion: Large scale phenotyping of blood group antigens enables the identification of blood donors with rare blood groups for patients with rare phenotypes or with antibodies to high-frequency antigens and to frequent antigens within one or more blood group systems.

Rh Alloantibodies in Rh D Negative Blood Group Pregnant Women - A Regional Transfusion Centre Study

Objective: To determine the frequency of Rh alloantibodies in pregnant women of the Rh-D negative blood group.&#x0D; Study Design: Cross-sectional study.&#x0D; Place and Duration of Study: Armed Forces Institute of Transfusion (AFIT) Rawalpindi, from Jan to Dec 2017.&#x0D; Methodology: The blood samples of pregnant women received for blood grouping, cross matching and antibodies screening were included in the study. The blood was typed for Rh-D along with ABO blood groups by Column Agglutination Technique (CAT), commonly known as the gel card method. Then, the samples included in the study were subjected to antibody screening by three cell antibody screening panel (Dia Cell, a product of Bio-Rad) by Column Agglutination Technique. The samples with positive antibody screening were further processed by 11 cell antibody screening panel (Dia Cell, BioRad) for Rh antibody identification by Column Agglutination Technique, the same as the indirect antiglobulin test (IAT).&#x0D; Results: 453 Rh-D negative pregnant women were screened for alloantibodies during the study period. Rh alloantibodies were present in 55 (12.08%) cases. The most common alloantibody identified was anti-D in 48 (87.3%) samples, followed by anti-C in 6 (10.9%) and anti-E in 1 (1.8%) case.&#x0D; Conclusion: The most prevalent Rh alloantibody identified in Rh-D negative pregnant women was anti-D, while the anti-C and anti-E were less prevalent. However, no case of anti-c and anti-e alloantibody was identified.

The spectrum of ABO haemolytic disease of the fetus and newborn in neonates born to group O mothers.

ABO haemolytic disease of the fetus and newborn (HDFN) is a lesser recognized entity; however, the severity may vary in neonates. This prospective observational study was performed to determine the severity and risk of ABO-HDFN in neonates born to O group mothers. A total of 260 neonates born to non-alloimmunized blood group O mothers were recruited. Blood group O neonates were excluded from the study. Neonatal direct antiglobulin test (DAT) was performed using the column agglutination technique. They were monitored for clinical and laboratory parameters and followed up at 6-8 weeks. The maternal anti-A and anti-B titres (IgM and IgG) were also done. A total of 176 neonates with blood group A (77/260; 29.6%) and B (99/260; 38.1%) were finally included in the study, and 15 (8.5%) of them were DAT positive. Overall, 26.7% (47/176) neonates received phototherapy, 172 (97.7%) survived and none required readmission. The median (inter-quartile range [IQR]) maternal IgG anti-B titre (32 [32-64]) was significantly higher (p < 0.001) than the IgG anti-A titre (16 [8-64]). The maximum total serum bilirubin in neonates had a significant positive association with neonatal birth weight (p=0.045), positive DAT (p=0.006) and requirement of phototherapy (p < 0.001). The relative risk (95% CI) of a DAT-positive neonate requiring phototherapy was 4.55 (3.12-6.33). The frequency of ABO incompatibility in neonates born to group O mothers was 67.69% (176/260). The maternal IgG titre of ≥64 could be a good predictor for identifying the neonates at risk of developing hyperbilirubinaemia requiring phototherapy.

Red Cell Antibodies Against High Frequency Antigens, A Two Year Experience At A Regional Transfusion Institute

Objective: To assess the clinicohaematological presentation and outcome of patients with antibodies to high frequency antigen(HFA) in our setup.Study Design: Cross sectional study.&#x0D; Place and Duration of Study: Armed Forces Institute of Transfusion, Rawalpindi, from Jan 2016 to Jan 2018.&#x0D; Methodology: We diagnosed 29 cases of uncommon red cell antibodies including antibodies to HFA, in a span of two years (2016-2018). Information regarding patient’s age, diagnosis, transfusion history, incompatible cross match and history of pregnancy was obtained. Venous blood sample of 3ml was taken in EDTA for grouping, red cell phenotyping and Direct AntiGlobulin Test (DAT) and 5 ml venous blood was taken for Indirect Antiglobulin Test (IAT), antibody screening and identification. Tube method was used for forward and reverse blood grouping, DAT and IAT. Column Agglutination Technique (CAT) was used for antibody screening, identification and red cell phenotyping.&#x0D; Results: Out of a total of 29 cases, 24 (83%) were of anti H antibody (Bombay blood group). Rest of 5 (17%) included one each of anti Rh 17, anti Rh 29 (Rh null), anti P1Pk, anti-ENA/WRB and anti P antibodies. Anti H Lectin (Ulexeuropaeus) was used for confirmation of H antigen absence, while rest of antibodies were confirmed by IBGRL Bristol, UK.&#x0D; Conclusion: The sources of antigen negative blood are family members, rare donor registry, autologous donations and frozen blood banks. Finding compatible blood for patients with an antibody to HFA may be a challenge.

Comparative Evaluation of heat-inactivated ABO isoagglutinin titers with solid-phase red cell adhesion titers

Background and Objectives: Measurement of actual concentration of IgG requires methods like heat inactivation (HI) of serum. This study was aimed at comparing of heat-treated ABO titers performed by conventional test tube technique (CTT) and column agglutination technique (CAT) with hemagglutination (HA)/solid-phase red cell adherence (SPRCA). Methods: This was a prospective, observational study conducted between October 2019 and March 2020. All consecutive A, B, and O group donors who gave consent for participation in the project were included. All samples were tested by CTT and CAT before and after HI (post DTT treatment performed by CTT [pCTT] and post DTT treatment performed by CAT [pCAT]) and with HA/SPRCA. Results: A total of 300 donors were included: 100 each with A, B, and O blood groups. For group O, IgG titers were higher than IgM titers among group O, whereas that among group A and group B, IgM titer was found to be higher than IgG titer by both HA/SPRCA and pCTT. The titer values among all the three blood groups were highest when the test was performed by pCAT, though the results of pCTT and SPRCA, pCTT, and pCAT were significant in group O donors. For groups A and B, results of pCTT and pCAT, pCAT, and HA/SPRCA were found to be statistically significant. Conclusion: Results obtained by HA/SPRCA were closer to pCTT, with respect to time consumption, expertise required, and lack of inter-observer variation. Titers obtained by pCAT were higher in comparison to pCTT obviously due to its relative higher sensitivity. Hence, these methods cannot be used interchangeably.