Conventional Tube Technique Research Articles

Hattrick of H-deficient phenotypes at a tertiary care health center in India

Abstract: H-deficient phenotypes, commonly known as Bombay blood type, have more inclination to be found in the Indian subcontinent, and conventional gold standard tube techniques are still the recommended method to identify them, provided a strict adherence to testing protocol. There is more to these phenotypes than just the bombay blood type. This brief communication highlights the identification of three H-deficient phenotypes from a single center that adhered to standard operating procedures and basic testing methodologies. It emphasizes the requirement of indirect Coombs test with pooled “O” cells with blood grouping of every sample irrespective of the testing platform and also the H antigen typing on encountering any suspicion. These H-deficient individuals may not be as rare as we assume them to be provided there are reframed testing policies. Although international collaborations and databases like the International Society of Blood Transfusion database have made it easier to record and share knowledge on blood types, a National network and registries of these rare phenotypes are essential to make them available to the general population who actually benefit from them.

A rare case of ABO grouping discrepancy due to probable blood group switching which presented as lost antigens detectable only with indigenous reagents in less sensitive platforms compared to highly sensitive automated platforms using non indigenous reagents

Abstract: Blood group switching in the form of loss or diminished expression of RBC antigens has been reported in malignancies and infections. Blood group antigens are present on the red cell surface. ABO blood group system is the most clinically significant system. Some cases can present as grouping discrepancy. Here we present a rare case of ABO grouping discrepancy due to probable blood group switching which presented as lost antigens detectable only with indigenous reagents in less sensitive platforms compared to highly sensitive automated platforms using non indigenous reagents. 66 year old female whose historic blood group was A Rh D positive with history of uneventful transfusion of 2 units of A Rh D positive packed red cell one and half years back now presented with mycoplasma pneumonia and acute pulmonary edema. On routine complete blood count testing her hemoglobin was 3.6 gm%, request send to blood bank for pretransfusion testing. Testing performed via conventional tube technique and ABO blood group discrepancy was noted with forward grouping turned to be A Rh D positive (positive reaction with anti A1 lectin) and on reverse grouping 3+ reactions was observed in both A and B cell giving a picture of O blood group. Blood grouping was performed in different platforms including fully automated, semi automated and manual using commercially available antisera and human plasma as a source of anti A, anti B antibodies for forward grouping. The antisera used in automated platforms are non indigenous and that for manual are indigenous. Discrepancy was noted (Forward A and Reverse O) in CTT with commercially available antisera and human plasma as reagents for forward grouping .The same discrepancy was noted with CAT in neutral card with commercially available antisera for manual grouping. But when grouping performed with Column Agglutination Technology using matrix grouping gel card the discrepancy was resolved reporting the blood group as O. For further confirmation we repeated the blood grouping in another fully automated platform, SPRCA Technology (Immucore NEOIRIS) and in that also no discrepancy noted giving a picture of O group. This patient probably had undergone a blood group switching from A to O by losing some but not all A epitopes and started anti A antibody production. Some A epitopes which were not lost had been picked up by the commercially available antisera intended for manual grouping. These antisera are indigenous in origin. Also when human plasma was used as source of antibodies the A epitopes which were not lost were detected. But when grouping was done with non-indigenous antisera in both manual and automatic platform the A epitopes were not detected. This case points towards the relevance of incorporating indigenous antisera in automated platforms.

Harnessing the potential of blood donors negative for high prevalence Rh antigens: A database initiative for thalassaemia care

Background and objectivesWith increasing life expectancy and prevalence of thalassaemia, it has led to a greater need for safe blood, yet the current supply from voluntary donors is insufficient to meet this demand. Thalassaemia recipients face a significant risk of alloimmunization because of repeated exposure to foreign red cell antigens. Study aims to determine high prevalent Rh antigen negative donors in western India donor population along with what percentage of these donors are willing to become dedicated voluntary donors for thalassaemia patients. Study also aims to examine factors influencing their willingness and challenges faced in mobilizing dedicated donors. Method700 whole blood donors from western India, following screening for inclusion & exclusion criteria as per Drugs and Cosmetic Act (DCA) 2020 amendment guidelines & were sero-negative for transfusion transmitted infections were enrolled for the study. Red cell phenotyping was performed using Conventional Tube Technique (CTT) for “D”, “C”, “E”, “c”, “e” and “K” antigen using known antisera. Donors that were “C” AND/OR “e” antigen negative were contacted telephonically and were counseled and motivated for becoming voluntary blood donors. Statistical analysis assessed correlation between donation frequency, donor’s occupation and education. ResultAmong 700 donors, 96.6% (n = 676) were males and 3.4% (n = 24) were females. The most predominant blood group was B > O > A > AB. Rh(D) antigen was present in 91.44% (n = 640) and absent in 8.6% (n = 60). Prevalence of other Rh antigens is as follows: “e” (99%) > “C” (85.4%) > “c” (59.1%) > “E” (18.0%). Only 1.15% had “K” antigen positive. The commonest Rh phenotype R1R1 (DCe/DCe) was expressed by 40.57% (n = 283), and the least common r″r (cE/ce), r″r″ (cE/cE) and r′r′ (Ce/Ce) was found in 0.14% (n = 1), respectively. ‘C’ negative, ‘e’ negative, ‘C’ and ‘e’ antigen negative donors constituted 14.8% (n = 104) with 93.2% (n = 97) C-antigen negative, 1.92% (n = 2) e-antigen negative and 4.8% (n = 5) both “C” and “e” antigen negative donors. The commonest phenotypes among C-antigen and e-antigen negative donors were rr (50%) and RzR2 (1.94%) respectively. Likewise, the most common phenotype amongst both C- and e-antigens negative donors was R2R2 (3.84%). 61.5% of the donors agreed to enroll for voluntary blood donation following telephonic invitation, while 6.8% of them refused permanently. Approximately, 3.9% of the blood donors were willing to donate blood only when needed and 27.8% of them could not be contacted. ConclusionCreating a database of voluntary donors with known phenotype, especially who lack very common antigens like “C” and “e” and are willing to become dedicated, regular voluntary donors for thalassemic patients can ensure timely administration of safe blood. One of the major challenges for this noble initiative was lack of awareness which can be circumvent effectively with proper counseling efforts.

Blood cross-matching using gel card technique compared to conventional tube technique: A diagnostic evaluation study

Abstract Background: Conventional tube technique (CTT) is the most commonly used method for blood cross-matching in India. The gel card technique is the latest technique emerged and due to its accurate results, it is considered a method of choice for cross-matching. Objective: The objective of the study was to compare blood cross-matching using the gel card technique compared to CTT with and without anti-human globulin (AHG). Materials and Methods: A diagnostic evaluation study was conducted on 1500 blood samples. Patients’ blood samples were sent to the blood bank for routine cross-matching procedures. Both tube and gel techniques were used for Coombs cross-matching and their results were compared and analyzed. Results: In our study, males were slightly more than females. The most common indication for blood transfusion was associated with medical conditions (28.4%). The gel card technique was as accurate as CTT with AHG. It was 100% sensitive and specific. At the same, the positive predictive value (PPV) and negative predictive value (NPV) are also 100%. The CTT sensitivity was 98.99% and it was 100% specific. The PPV was also 100% but the NPV was only 37.5% which means that the false-positive rate was very high with CTT compared to CTT with AHG. Because CTT without AHG in present study showed more false positive results as compared to gel matrix. The average time required for a single compatibility test by gel card method was 25 ± 3.5 min, while that for CTT with AHG was 90 ± 4.9 min (indirect antiglobulin test [IAT]) and 30 ± 3.8 min if IAT was not done. Thus, even though CTT with AHG was equally effective as that of the gel card method, but time taken was significantly more (P < 0.05). Conclusion: The gel technique has definite advantages over the tube technique because of being able to give more accurate results, less chances of false-positive and false-negative results, interpretation of results more objective consistent and reproducible, and its shorter duration for cross-matching. However, in developing countries like India, the gel technique if applied widely, costs factor would come down and could be considered a better alternative to CTT to ensure successful transfusion.

Anti-A and anti-B titers in A, B and O whole blood donors: Beyond “dangerous O”

Background and ObjectivesHemolytic transfusion reactions (HTRs) pose significant risks in transfused patients, with anti-A and anti-B antibodies in donor plasma being potential contributing factors. Despite advancements in component preparation, HTRs remain a concern, particularly with apheresis-derived platelets. This study aimed to determine the prevalence of high anti-A and anti-B titers among A, B, and O blood group donors and to explore factors associated with high titers. Materials and MethodsA cross-sectional observational study was conducted over 18 months, enrolling 978 participants from a tertiary care teaching hospital in Western India. Anti-A and anti-B titers were determined using the Conventional Tube Technique (CTT). Statistical analysis assessed correlations between high titers and demographic factors. ResultsThe majority of participants were young males (98.8%). Prevalence of high titers for IgM anti-A was 12.2% and IgG anti-A was 2.5%. For anti-B, IgM titers were 2.3% and IgG titers were 0.2%. The prevalence of dangerous O was found to be 14.1%, while 3.52% and 10.5% of A and B blood group donors were found to have high titers, respectively. Factors associated with high titers included female gender, vegetarian diet, age <30 years, and O blood group. ConclusionThe study sheds additional light and provides supplementary information regarding the prevalence and correlation of high anti-A and anti-B titers among O, A and B blood donors. Understanding these factors is crucial for optimizing transfusion safety protocols, including selective screening of platelet units and tailored transfusion strategies based on donor characteristics.

Characterization of GYP(B-A-B) hybrid glycophorins among Thai blood donors with Mia-positive phenotypes.

GYPA and GYPB genes encode the antigens of the MNS blood group system carried on glycophorin A (GPA) and glycophorin B (GPB), or on a hybrid molecule of GPA and GPB. GP hybrid variants are created through unequal crossing over and gene conversion, typically from the parent genes GYPA and GYPB. In the present study, we characterized the GYP(B-A-B) hybrid variants among Thai blood donors with Mia-positive phenotypes using PCR-based coupled to DNA sequencing techniques. Altogether, 1,020 samples from Thai blood donors were tested with anti-Mia by conventional tube technique (CTT). Polymerase chain reaction with sequence-specific primer (PCR-SSP) was initially used to differentiate normal GYPB, GYP*Vw and groups of GYP*Hut, GYP*Mur, GYP*Hop, GYP*Bun and GYP*HF alleles. Subsequently, GYP(B-A-B) hybrid variants were investigated using DNA sequencing. Among 1,020 blood donors, 127 (12.45%) were Mi(a+) phenotypes. The comparison Mia typing results between CTT and PCR-SSP were concordant. All Mi(a+) samples were positive with only group of GYP*Hut, GYP*Mur, GYP*Hop, GYP*Bun and GYP*HF alleles by PCR-SSP. Regarding the sequencing results, 115/1,020 (11.27%) donors carried the GYP*Mur, of which 111/1,020 (10.88%) were GYP*Mur/GYPB heterozygotes and the other 4/1,020 (0.39%) donors were GYP*Mur/GYP*Mur homozygotes. The remaining 12 donors included different GYP*Bun-like alleles; 11 of them (1.08%) were GYP*Thai/GYPB heterozygotes, and one (0.10%) was GYP*Thai II/GYPB heterozygotes. With 5.83% (119/2,040) of the total hybrid alleles, GYP*Mur was the predominant allele. The GYP*HF, GYP*Bun, GYP*Hop and GYP*Kip alleles were not observed in this study. Regarding the hybrid GP variants, a consensus of observed prevalent GYP*Mur and GYP*Bun-like alleles, respectively, was identified in the Thai population. The introduction of our strategy has allowed us to identify the zygosity for GYP hybrid variants, particularly GYP(B-A-B) hybrid genes, when antisera are unavailable and lacking adequate phenotypic features to determine GP variants.

A comparative study to assess diagnostic efficacy of micro typing gel technique versus conventional tube technique in blood cross-match in blood bank at a tertiary care hospital

Abstract: BACKGROUND: In transfusion medicine, cross-matching and compatibility are determined using the conventional tube approach. The goal of the current study is to compare the microtyping gel approach to the conventional tube method for studying blood cross-match. OBJECTIVES: The objective of the study was to assess the compatibility of donor’s blood with recipient blood by microtyping gel technique and conventional tube technique and comparison of advantages and disadvantages of the two techniques. MATERIALS AND METHODS: This observational, cross-sectional study investigation was carried out in a tertiary care facility’s blood bank for 1½ years. It was decided to compare the effectiveness of the traditional tube and gel techniques. RESULTS: In the current investigation, we evaluated the age of the study participants and found that the majority of the study participants were male (63.17%) and most of them were between the ages of 21 and 40 years. The men-to-women ratio in this study was 1.71:1. About 2300 blood samples were subjected to compatibility testing using both the traditional test tube technology and the microtyping gel technology. The conventional method and the gel card approach are equivalent in terms of sensitivity and specificity. However, the gel card approach is simple to use, quick, reliable, and allows for the recording of data. The spin saline tube approach, in comparison, takes longer and produces unreliable results. This makes the gel card approach preferable to the conventional method. The findings were examined. CONCLUSIONS: Although the conventional tube technology is still regarded as the gold standard for pretransfusion analysis, it nevertheless has several drawbacks and relies on the precise hand–eye coordination of the laboratory staff. We advise using the microtyping gel approach due to its ease of use, stability of outcomes, dispensing of controls and absence of washing process, and equivalent specificity and sensitivity.

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.

Application of a simplified PCR-SSP method to detect A4GALT*01 and A4GALT*02 typing among Thai blood donors.

An intronic A4GALT single nucleotide variant, rs5751348:G>T, P2 or A4GALT*02 allele has a lower level of the enzyme-encoding A4GALT transcripts than the P1 individuals. Here, we first develop and validate a simple inhouse PCR-SSP method to detect A4GALT*01 and A4GALT*02 alleles, and second, apply this method to compare the allele frequencies between Thai and other populations. The conventional test tube technique was used to detect the P1 antigen in 222 blood samples from Thai blood donors at Thammasat University Hospital. A PCR-SSP method was optimized and validated for reproducibility and specificity to identify these alleles and was subsequently tested on 1,840 DNA samples of unknown phenotypes obtained from central, northern and southern Thais. In addition, allele frequencies of central Thais were compared with those of other populations. In the tested cohort (n=222), P1 and P2 phenotypes were typed in 26.13 and 73.87% of donors, respectively. The developed PCR-SSP was successfully optimized, and the outcomes were consistent with those of serological phenotyping and DNA sequencing results, demonstrating its validity for predicting P1/P2 phenotype. For central, northern and southern Thais, the A4GALT*01 frequency was 0.1579 (430/2,724), 0.1183 (71/600), and 0.2575 (206/800), whereas the A4GALT*02 frequency was 0.8421 (2,294/2,724), 0.8817 (529/600), and 0.7425 (594/800), respectively. Their observed frequencies among central Thais significantly differed from those in other populations (p<0.05). Our study has successfully developed a simple, precise, and reliable method to genotype A4GALT*01 and A4GALT*02 using inhouse developed PCR-SSP for predicting P1/P2 status.

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.

Role of antibody screening in high titre group O donors

Red Cells, Fresh Frozen Plasma (FFP) and Platelets (RDP/SDP) prepared from donors with group O may have high titers of anti-A, anti-B and/or anti-A,B antibodies. When such components given to non-group O patients, this high titre can result in haemolytic transfusion reactions (HTRs). Such group O donors are generally termed ‘high-titer group O donors. Significant amounts of ABO antigen being present on the platelet surface and anti-ABO iso-agglutinins being present in the donor’s plasma, Platelet transfusions need to take into account the issues. Although relatively rare, but acute intravascular haemolytic transfusion reaction has been caused by passive transfer of anti-A and anti-B antibodies, present in group O donors. This study aimed to identify the prevalence of high titre antibodies in group O donors. Thus, titre are performed in randomly selected group O donors from different gender and age group to identify best available source of products for Platelet and follow up transfusions.: Randomly selected 100 O blood group donors were included in the study. Samples from these donors were tested for ABO antibody (both IgM and IgG) titres using conventional tube technique at RT and 37°C at Indirect Antiglobulin phase. Statistical analysis was performed using two sample t-test and anova test.Donors included in the present study were mainly male (85%) donors. ABO antibody titres ranged from 0 to 2048. In the present study, Anti-B (IgG) titer is significantly higher than other antibodies in both genders.There are a large proportion of group O donors having high titres of antibodies and hence a routine pretransfusion screening for such antibodies can prevent the development of hemolytic transfusion reaction by issuing only low titre components for out of group transfusions.Each Blood Transfusion Service should establish a policy for testing and issue of group O platelets to non-O group recipient to avoid chances of development of adverse transfusion reaction.

Direct antiglobulin test positivity in Serbian blood donors in the era of gel card technology.

In the era of gel cards, we aimed to determine the incidence of a positive direct antiglobulin test (DAT) in a population of blood donors in Serbia and to compare results with the period when a conventional tube technique was used. A retrospective study was conducted on 184,171 blood donors over 10 years (2012-2021). Positive DAT results initially were detected after positive result of the compatibility test. After a DAT had been initially performed on fresh blood samples, a control DAT was performed 6 months later. Using gel cards, we found a low incidence (0.09%) of DAT positivity among 55,254 female and 128,917 male blood donors, with no difference found in the occurrence of a positive DAT between them. Positive DAT moderately positively correlated with increasing age of blood donors, but without statistical significance. The vast majority of blood donors (98.86%) were IgG positive. All donors were in good health, did not take medication or had anaemia or haemolysis. During the period 1980-1989, when the test tube technique was used, we found 0.05% DAT-positive blood donors. The incidence of positive DAT results in Serbian blood donors is higher compared with that found using the previous test tube technique, but the incidence is consistent with the findings of other studies.

Phenotypic and Allelic Frequency of ABO and Rh (D) Blood Group among Whole Blood Donors in a Teaching Hospital of Chhattisgarh

Background: ABO and Rh (D) blood groups are the most important in blood transfusion and are determined genetically. Although these blood groups are common to all humans, there is variation in their allelic frequency based on region and population. This study was performed to determine the allelic frequency of ABO &amp; Rh (D) in the donor population in the Blood Center of Chhattisgarh located in Central India.&#x0D; Place and Duration of Study: It is a cross-sectional study performed in the Department of Transfusion Medicine &amp; Blood Bank of a teaching hospital from July 2021-February 2022.&#x0D; Methodology: Only the accepted whole blood donors were included. ABO &amp; Rh (D) blood grouping was performed by conventional tube technique and their allelic frequency was determined. We studied 4078 whole blood donors out of which 4055 were males and 23 were females.&#x0D; Results: Phenotypic frequency of ABO blood group system was O&gt;B&gt;A&gt;AB. Rh (D) positive was more prevalent than Rh (D) negative. Allele frequency of ABO system was 0.1545 for IA, 0.2351 for IB, and 0.6105 for IO. In Rh system, allele frequency of ID was 0.8441 and Id was 0.1559.&#x0D; Conclusion: Phenotypic &amp; allelic frequency of ABO &amp; Rh (D) shows heterogeneous distribution in different parts of the world. Our study showed blood group O &amp; allele IO as the most common. This data is of utmost importance in the planning of transfusion services, especially during a healthcare crisis in low-resource area like ours.

A COMPARISION OF CONVENTIONAL TUBE METHOD AND COLUMN AGGLUTINATION TECHNOLOGY IN AN IMMUNOHEMATOLOGY LABORATORY

Background: Rapid technological advancements in pretransfusion procedures in an immuno-hematological laboratory are a result of the increased focus on the quality and safety of blood products. Numerous automated pretransfusion testing platforms have been developed as a result of the inherent drawbacks of the gold standard conventional tube method. The invention of Column Agglutination Technology was the biggest advancement among these. Aim: 1. To compare the results of blood grouping and crossmatching by Conventional Tube Method and Column Agglutination Technology. 2. To statistically evaluate the results obtained between Column Agglutination Technology and Conventional Tube Technique in our immunohematology laboratory. Materials and Methods: The study was performed in blood bank of a tertiary hospital in Mangalore during the month of January,2022 in which 500 samples were subjected to blood grouping and cross matching. The data obtained was extensively studied. Sensitivity, specicity and statistical analysis were done by Fisher's exact test. Results: In comparative evaluation of CAT and CTT of 500 samples, there was concordance rate of 99.6% in blood grouping and concordance of 99.8% in crossmatching. In both the scenarios, the discordance was evaluated and found CATis superior to CTT. The most common blood group of both studies was 0 positive. Statistical analysis using Fisher's test proved statistically signicant difference between grouping and cross-matching via both tests with a p value of 0.000001 and 0.01 respectively. The sensitivity and specicity of both tests showed CAT to be superior with 100% sensitivity and 100% specicity while in CTT, the sensitivity was 100% with 66.6% specicity. Conclusion: The study establishes that CAT is more sensitive, specic, rapid, reliable procedure and is a better substitute of CTT in pretransfusion testing.

Extended red blood cell antigens and phenotypes in Burkina Faso: potential issues to design local population-sourced red blood cell reagent panels.

To date, 43 blood group systems with 349 red blood cell (RBC) antigens have been recognized. The study of their distribution is useful for blood services to improve their supply strategies for providing blood of rare phenotypes, but also to design indigenous RBC panels for alloantibody screening and identification. In Burkina Faso, the distribution of extended blood group antigens is not known. This study aimed to investigate the extended profiles of blood group antigens and phenotypes of this population and to raise limitations and potential strategies for the design of local RBC panels. We conducted a cross-sectional study that included group O blood donors. Extended phenotyping for antigens in the Rh, Kell, Kidd, Duffy, Lewis, MNS, and P1PK systems was performed using the conventional serologic tube technique. The prevalence of each antigen and phenotype combination was determined. A total of 763 blood donors were included. The majority were positive for D, c, e, and k and negative for Fya and Fyb. The prevalence of K, Fya, Fyb, and Cw was less than 5 percent. The most frequent Rh phenotype was Dce, and the most common probable haplotype was R0R0 (69.5%). For the other blood group systems, the K-k+ (99.4%), M+N+S+s- (43.4%), and Fy(a-b-) (98.8%) phenotypes were the most frequent. Antigenic polymorphism of blood group systems by ethnicity and geography argues for the design and evaluation of population-sourced RBC panels to meet specific antibody profiles. However, some of the specificities identified in our study, such as the rarity of double-dose antigen profiles for certain antigens and the cost of antigen phenotyping tests, are major challenges to overcome.

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.

Can Donor Demography or Anthropometry be Used as a Screening Tool for Identifying Potential Low ABO-Titer Plasma?

Background and Aims: Titration is a time-consuming procedure even when automated. The aim of the present study was to identify the variation in ABO titers with donor characteristics in Group O individuals. Materials and Methods: This was a prospective, observational study conducted from January 2019 to March 2020. All consecutive O group donors were included. All samples were tested by conventional tube technique (CTT). Demographic and anthropometric details of the donors such as gender, age, religion, height, weight, first-time/repeat donor, and state of residence were recorded. The high-titer group included individuals with anti-A and anti-B ≥128, and the low-titer group included individuals with anti-A and anti-B &lt;128. Results: A total of 2000 Group O whole blood donors were included. A higher percentage of donors were older than 30 years of age (55.3%), males (90.7%), Hindu (87.15%), belonging to Uttar Pradesh (70.85%), height more than 160 cm (88.85%), weight more than 65 kg (82.2%), body mass index (BMI) more than 23 (86.15%), body surface area more than 1.7 m2 (89.95%), and first-time donors (68.4%). The donor age, height, weight, BMI, and body surface area were found to have a weak correlation with anti-A and anti-B titers performed by CTT. The correlation between female and male gender was poor in high- as well as low-titer category. Conclusion: A definite variation in antibody titers is seen with a change in donor demographics and anthropometrics. However, none of the variables helps as a screening tool for identifying the North Indian healthy donors who possess a high or low titer.

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.

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 Rare Case of Bm (Bweak) Phenotype Detected in a Healthy Blood Donor from Eastern India

A 52-year-old male repeats voluntary blood donor donated at our blood center for the first time. Historical blood group was O, Rh (D) positive. Initial blood grouping was done on the fully automated immunohematology analyzer using column agglutination technique (CAT). Discrepant results (forward as group O and reverse as group B) were observed while performing the ABO blood grouping by CAT. Repeat testing by conventional tube technique showed the same discrepancy. Antibody detection test and direct antiglobulin test results were negative. After adsorption-elution, the eluate reacted only with group B red cells. Saliva testing for secretor status shows the presence of B and H substances. Finally, it was classified as a case of Bm (now called Bweak) phenotype. As a precautionary measure, the donor was recalled and a special blood group card was issued with a clear mention of his respective donor and recipient status. This case showed the importance of ABO subgroup determination that can help blood centers to establish defined transfusion protocol and prepare an elaborate rare blood donor registry.