Routine group and save screening prior to emergency laparoscopic surgery.

INTRODUCTION: Two group and save (G&S) samples are routinely collected from patients undergoing diagnostic laparoscopy and/or emergency appendicectomy. We aimed to identify the necessity of this practice by looking at the perioperative transfusion rates. METHODS: Data were obtained from our electronic theatre system for all patients who underwent emergency laparoscopic surgery (specifically diagnostic laparoscopy and/or laparoscopic appendicectomy) between January 2017 and December 2018. Records were reviewed for the number of G&S samples sent and perioperative transfusion rates. RESULTS: A total of 451 patients were included in the study. The numbers of procedures performed in 2017 and 2018 were 202 (44.8%) and 249 (55.2%), respectively. The total number of samples sent was 930. Only 786 (84.5%) samples were processed and the rest were rejected for various reasons. Of the 451 patients included in the study, 308 (68.3%) had two G&S samples sent, whereas 41 patients (9.1%) had only one G&S sample sent. Fifty-six (12.4%) and 20 (4.4%) patients had three and four G&S samples sent, respectively. Only two patients required transfusion perioperatively (0.4%), and the indication in both was irrelevant to the primary operation. CONCLUSIONS: These results demonstrate a near-zero transfusion rate in this patient cohort. Omitting G&S is safe and potentially saves time and resources.

Assessing the Necessity of Routine Crossmatching for Blood Transfusion in Renal Transplantation.

INTRODUCTION: Routine crossmatch of packed red blood cells (pRBCs) is completed preoperatively at many centers despite conflicting evidence on the incidence of blood transfusions with renal transplantation. In the current economic climate, resource adjudication should be judicious and medically appropriate. The objective of this study was to determine the incidence, timing, and predictors of early postoperative pRBC transfusion in patients undergoing renal transplantation. METHODS: A retrospective review of all patients undergoing renal transplantation at our institution from January 2013 to May 2016 was performed. Demographic, biochemical, and clinical parameters were recorded. The primary outcome was early postoperative transfusion, defined as an intraoperative transfusion or within 2 days of surgery. Multivariable logistic regression was performed to identify associations with early postoperative transfusion. RESULTS: We identified 428 patients during the study period (average age 55 years, 60% male, 30% obese, 67% deceased donor, and 43% preoperative antithrombotic use). Forty (9.3%) patients required early postoperative transfusion (mean: 2.8 pRBCs/transfusion) and most did not require blood urgently. Only 20 (4.7%) patients required a transfusion intraoperatively or on the same day of surgery. Lower preoperative hemoglobin (per g/L unit: odds ratio [OR]: 0.943), female gender (OR: 2.752), and preoperative antithrombotic use (OR 2.369) were associated with a need for early postoperative transfusion. CONCLUSION: Transfusion in the early postoperative period following renal transplantation was less than 10%, suggesting that routine crossmatch may not be necessary for all patients. Preoperative hemoglobin, female gender, and preoperative antithrombotic use were associated with increased risk and may be useful to risk-stratify patients who require crossmatch.

A comparison of three column agglutination tests for red blood cell alloantibody identification.

OBJECTIVE: Commercial kits of column tests for pre-transfusion testing have progressively replaced conventional tube tests in most laboratories. Aim of this study was to compare three commercial test cell panels for the identification of irregular red blood cell (RBC) alloantibodies. Overall, 44 samples with a positive indirect antiglobulin test (IAT) by routine testing were used for comparison of following panels: Ortho RESOLVE® panelC (Ortho Clinical Diagnostics (OCD), Milan, Italy), ID-DiaPanel(-P) (Bio-Rad Laboratories, CA, USA) and Identisera Diana(P) (Grifols, Barcelona, Spain). Column agglutination techniques were used, with microtubes containing either microgel (Bio-Rad/Grifols) or glass bead microparticles (Ortho). RESULTS: Alloantibody identification was possible in 38 samples, of which identical identification was shown in 33 samples by all methods. The remaining samples showed differences between certain methods, with the gel card system being superior to the glass card system for analyzing stored samples Considering that not all samples were evaluated in all three methods, the concordance rate reached 100% between Bio-Rad and Grifols, 90.5% between Bio-Rad and OCD, 86.5% between OCD and Grifols and 90.5% between all methods. Although differences in sensitivities were seen for specific antibodies, the three methods showed comparable performance for the identification of RBC alloantibodies.

Safety profile and impact of low-titer group O whole blood for emergency use in trauma.

PURPOSE: Following US military implementation of a cold-stored whole blood program, several US trauma centers have begun incorporating uncrossmatched, group O cold-stored whole blood into civilian trauma resuscitation. We set out to evaluate the safety profile, transfusion reactions events, and impact of low-titer group O whole blood (LTO-WB) at our center. METHODS: In November 2017, we added LTO-WB to each of our helicopters and to our emergency department (ED) refrigerator, alongside that of existing red blood cells and plasma. We collected information on all patients with trauma receiving prehospital or ED transfusion of uncrossed, emergency release blood products between November 2017 and June 2018. Patients were divided into those receiving any LTO-WB and those receiving only red blood cell and or plasma (COMP). Serial hemolysis panels were obtained at 3 hours, 24 hours, and 48 hours. All data were run using STATA 12.1. Statistical significance was set at p < 0.05. RESULTS: One hundred ninety-eight patients received LTO-WB and 152 patients received COMP. There were no differences in age, sex, or mechanism. The LTO-WB patients had higher chest Abbreviated Injury Scale scores (median, 3 vs. 2; p = 0.027), as well as worse arrival base excess (median, -7 vs. -5; p = 0.014) and lactate (5.1 vs. 3.5; p < 0.001). The LTO-WB patients received less post-ED blood products than the COMP patients (median, 0 vs. 3; p = 0.001). There was no difference in survival (LTO-WB, 73%; COMP, 74%; p = 0.805). There were only two suspected transfusion reactions, both in the COMP group (p = 0.061). There was no difference in hemolysis panel values. Controlling for age, severity of injury, and prehospital physiology, LTO-WB was associated with a 53% reduction in post-ED blood product transfusion (odds ratio, 0.47; 0.23-0.94 95% CI; p = 0.033) and two-fold increase in likelihood of survival (odds ratio, 2.19; 1.01-4.76 95% CI; p = 0.047). CONCLUSION: Low-titer group O whole blood has similar evidence of laboratory hemolysis, similar transfusion reaction rates, and is associated with a reduction in post-ED transfusions and increase likelihood of survival. LEVEL OF EVIDENCE: Therapeutic, Level II.

A novel approach to bedside pretransfusion identity check of blood and its components: the Sandesh Positive-Negative protocol.

BACKGROUND: Blood component mistransfusion is generally due to preventable clerical errors, specifically pretransfusion misidentification of patient/blood unit at bedside. Hence, electronic devices such as barcode scanners are recommended as the standard instrument used to check the patient's identity. However, several healthcare facilities in underdeveloped countries cannot afford this instrument; hence, they usually perform subjective visual assessment to check the patient's identity. This type of assessment is prone to clinical errors, which precipitates significant level of anxiety in the healthcare personnel transfusing the blood unit. Hence, a novel objective method in performing pretransfusion identity check, the 'Sandesh Positive-Negative (SPON) protocol,' was developed. METHODS: A nonrandomized study on bedside pretransfusion identity check was conducted, and 75 health care personnel performed transfusion. The intervention was performed by matching a custom-made negative label with blood component with the positive label of the same patient available at bedside who was about to receive transfusion. RESULTS: In total, 85.3% of the subjects were anxious while performing pretransfusion identity check based on the existing standard practice. After the implementation of the SPON protocol, only 38.7% experienced either mild, moderate or severe anxiety. The overall level of satisfaction also increased from 8.0% to 38.7% and none were dissatisfied. Although only 9.3% were dissatisfied about the existing practice, approximately 70.7% felt the need for a better/additional protocol. Clerical error was not observed. CONCLUSIONS: The SPON protocol is a cost-effective objective method that reduces anxiety and increases satisfaction levels when performing final bedside identity check of blood components.

Impact of Novel Monoclonal Antibody Therapeutics on Blood Bank Pretransfusion Testing.

Novel monoclonal antibody therapies are increasing in number and clinical significance as their role in oncologic formularies expands. Anti-CD38 and anti-CD47/SIRPα agents commonly interfere with pretransfusion compatibility testing. Anti-CD38 interference is mitigated by dithiothreitol, which disrupts CD38 antigen on reagent red cells; however, this modification limits rule-out of all clinically significant antibodies. Several anti-CD47 agents are in clinical trials and demonstrate wide variability in pretransfusion testing interference. Modifications to pretransfusion testing can limit interference by anti-CD47 agents. Rapid dissemination of knowledge of these monoclonal antibody agents to the broader transfusion medicine community is paramount for continued patient transfusion safety.

Impact of Genotyping on Selection of Red Blood Cell Donors for Transfusion.

Red blood cell (RBC) antigen phenotyping is an essential component of transfusion compatibility testing. Serology has been the gold standard method, but its low throughput and risk of diagnostic interference in certain situations limits its applicability. Genotyping is useful for phenotyping in these cases, providing a high-throughput and reliable alternative to serology. Genotyping is indicated in several hematology and oncology patient populations. Because genotyping requires a complex testing environment and bears an additional risk of genotype-phenotype discrepancy, its use is currently limited, but it serves as a useful adjunct and may eventually supplant serology as a new gold standard.

New rules of ABO-compatibility in kidney transplantation.

ABO compatibility rules in kidney transplantation have been deeply modified with the possibility of ABO-incompatible transplantation. The recipient has to be prepared in the days preceding surgery with an objective of ABO antibody titers of 1/8 or less. This is obtained through a procedure including antibody removal, rituximab and IV immunoglobulins alone or in association according to the initial titer. All ABO combinations are possible. Due to the preparation of the recipient, living related transplantation has been first carried out but ABO-incompatible transplantation from a deceased donor is becoming common practice in some countries (A2 or A2B donor to a B recipient). Lower uncensored graft survival has been reported by some studies but not when ABO-incompatible kidney transplantations were compared with matched ABO-compatible ones. The infectious risk in the perioperative period, consequence of higher immunosuppression, raises concern. The interlaboratory variability in hemagglutination anti-A/B assays remains an important question among cohort studies which leads to development of new tests. ABO-incompatible transplantation is associated with a rare process, accommodation, that is well known in xenotransplantation and according to which, the transplant is protected against the consequences of ABO antibody binding. In human kidney ABO-incompatible transplantation, few studies are available but suggest that this protection against the post-transplant antibody rebound might be mediated by the expression of anti-complement molecules by endothelial cells.

Mass-scale red cell genotyping of blood donors: from data visualization to historical antigen labeling and donor recruitment.

Donor red cell genotyping provides efficiencies to identify "in demand" blood donors for transfusion recipients requiring antigen-negative blood. Donor red cell genotype information can be used to label units with historical types and introduced throughout the supply chain from the blood center to the hospital transfusion service and has potential to be used in recruitment strategies.

Transfusion Safety: The Nature and Outcomes of Errors in Patient Registration.

The transfusion chain is susceptible to error at every step. Accurate patient registration is a key first step that links a patient with their historical medical profile, yet patient registration is marked by its own challenges. Registration errors are deviations from standard operating procedures that occur during the process of patient registration. A frequent consequence of registration errors is the obfuscation of historical information and patient misidentification. Through duplicate registrations, patient information can be spread across multiple records and through hybrid registrations information from multiple patients can be combined into a single record. Patients with the same core identifiers, and the misuse of health insurance information also pose a threat to accurate registration. In the context of transfusion, this can lead to ABO discrepancies, failing to match for previously identified alloantibodies, and redundant serological investigations. Other consequences include missed billing opportunities and the inadvertent sharing of medical information. Reducing the occurrence of registration errors can be achieved through a multifaceted approach combining targeted educational efforts with technological improvements to the registration system. A recent development being the use of biometric identifiers. Despite their frequency, published reports on the occurrence and underlying cause of registration errors are rare. Most reports are found within articles on general medical errors or misidentification events and consequently, the true rate of registration errors among health information systems is not known. Here we summarize literature pertaining to how and why registration errors occur and their implications in the context of blood transfusion.

Sensitive typing of reverse ABO blood groups with a waveguide-mode sensor.

Portable, on-site blood typing methods will help provide life-saving blood transfusions to patients during an emergency or natural calamity, such as significant earthquakes. We have previously developed waveguide-mode (WM) sensors for forward ABO and Rh(D) blood typing and detection of antibodies against hepatitis B virus and hepatitis C virus. In this study, we evaluated a WM-sensor for reverse ABO blood typing. Since reverse ABO blood typing is a method for detection of antibodies against type A and type B oligosaccharide antigens on the surface of red blood cells (RBCs), we fixed a synthetic type A or type B trisaccharide antigen on the sensor chip of the WM sensor. We obtained significant changes in the reflectance spectra from a WM sensor on type A antigen with type B plasma and type O plasma and on type B antigen with type A plasma and type O plasma, and no spectrum changes on type A antigen or type B antigen with type AB plasma. Signal enhancement with the addition of a peroxidase reaction failed to increase the sensitivity for detection on oligosaccharide chips. By utilizing hemagglutination detection using regent type A and type B RBCs, we successfully determined reverse ABO blood groups with higher sensitivity compared to a method using oligosaccharide antigens. Thus, functionality of a portable device utilizing a WM sensor can be expanded to include reverse ABO blood typing and, in combination with forward ABO typing and antivirus antibody detection, may be useful for on-site blood testing in emergency settings.

Preventing Mistransfusions: An Evaluation of Institutional Knowledge and a Response.

BACKGROUND: Blood product mistransfusions occur when a process error causes transfusion of incompatible blood products. These events are known sources of negative patient outcomes. One such event demonstrated an institutional knowledge gap and an opportunity to reduce this source of transfusion errors. The focus of this study was to evaluate the application of point of care cognitive aids to bridge potentially lethal knowledge gaps in blood product to patient compatibility. METHODS: A patient-donor ABO antigen compatibility grid for red blood cells (RBC) and fresh frozen plasma (FFP) was developed for creation of a cognitive aid and a blood product safety quiz. Participants included 117 registered nurses and postgraduate medical interns who were given 2 minutes to complete the quiz for establishing institutional controls. A separate group of 111 registered nurses and interns were given the same timed quiz twice, without and then with a blood product compatibility cognitive aid. An analysis of covariance was used to evaluate without cognitive aid versus with cognitive aid quiz results while taking the specialty (nurse versus interns) and baseline score into consideration. The blood bank adopted the grid as a forcing function to be completed before release of blood products. RESULTS: The correct RBC answer percentage increased from 84.7% to 98.3% without and with cognitive aid (average improvement 13.6%, standard deviation [SD] = 18.3%, 95% confidence interval, 10.1%-17.1%, P < .0001, ); the correct FFP answer percentage increased from 54.2% to 99.6% without and with cognitive aid (average improvement 45.4%, SD = 20.1%, 95% confidence interval, 41.7%-49.2%, P < .0001). Participants with lower baseline RBC and FFP score showed better improvement in the correct answer percentage for RBC and FFP (P < .001), respectively. CONCLUSIONS: The use of a cognitive aid for determining blood product ABO compatibility may improve performance during a time-limited test for matching correct patient and blood product ABO type. The use of the cognitive aid as a "forcing function" before the release of blood from the blood bank and before transfusion at the bedside may reduce transfusion mismatch associated with gaps in ABO compatibility knowledge.

A uniform method for the simultaneous blood group phenotyping of Fya , Fyb , Jka , Jkb , S, sÌ , P1, k applying lateral-flow technique.

BACKGROUND AND OBJECTIVES: A lateral flow assay for simultaneous blood group typing of ABO, RhD, C, E, c, e, Cw and K with stable end-point and without centrifugation is in routine use since several years (MDmulticard® ). The typing of extended phenotype parameters belonging to the Duffy, Kidd, MNSs blood group systems and others, however, has not yet been demonstrated for this technique. Reliable detection of Fyx , a weak Fyb phenotype with a pronounced quantitative reduction of the number of Fyb antigens on the erythrocyte surface, remains a weakness of current serological blood grouping techniques. MATERIAL AND METHODS: The performance characteristics of the following reagents were evaluated in donor and patient samples in lateral flow technology (MDmulticard® ): Anti-Fya , -Fyb , -Jka , -Jkb , -S, -s̅, -P1 and -k. The sensitivity to detect Fyx was in addition evaluated with Fyx positive samples, which had been preselected by MALDI-TOF MS-based genotyping. RESULTS: All results obtained with the MDmulticard® were in full accordance with those of the CE-certified reference products for all the eight reagent formulations used: Anti-Fya , -Fyb , -Jka , -Jkb , -S, -s̅, -P1 and -k. Also, all Fyx phenotypes of the selected population of 93 positive samples, originally identified by MALDI-TOF MS-based genotyping, were reliably detected by the lateral flow assay. CONCLUSION: Extended phenotype blood group parameters, including the serologically challenging Fyx phenotype, can be determined simultaneously, rapidly and accurately using the lateral flow (MDmulticard® ) technology, even in cases when IgG class antibodies are the only source of diagnostic antibodies.

Incomplete Antibodies May Reduce ABO Cross-Match Incompatibility: A Pilot Study.

OBJECTIVE: Any erythrocyte transfusion among humans having type A or B blood groups is impossible due to antibodies causing fatal transfusion complications. A cross-match test is performed to prevent immune transfusion complications before transfusion. Our hypothesis is that the fragment antibody (Fab) part of the antibody (incomplete antibody) may be used to prevent an immune stimulus related to the complete antibody. Therefore, we designed a pilot study to evaluate the effectiveness of these incomplete antibodies using cross-match tests. MATERIALS AND METHODS: Pepsin enzyme and staphylococcal protein A columns were used to cut anti-A and anti-B monoclonal antibodies and purify their Fab (2) fragments, respectively. An Rh-positive erythrocyte suspension with purified anti-A Fab (2) solution and B Rh-positive erythrocyte suspension with purified anti-B Fab (2) solution were combined correspondingly. Cross-match tests were performed by tube and gel centrifugation methods. The agglutination levels due to the anti-A and anti-B Fab (2) antibodies and their effects on the agglutination normally observed with complete antibodies were then measured. RESULTS: No agglutination for the purified incomplete anti-A Fab (2) with A Rh+ erythrocyte and anti-B Fab (2) with B Rh+ erythrocyte combinations was observed in the tube cross-match tests. These agglutination levels were 1+ in two wells in the gel centrifugation cross-match tests. Fab (2)-treated erythrocytes were also resistant to the agglutination that normally occurs with complete antibodies. CONCLUSION: We determined that the Fab (2) fragments of antibodies may not only be used to obtain a mild or negative reaction when compared to complete antibodies, but they might also be used for decreasing ABO incompatibility. Incomplete antibodies might be a therapeutic option in autoimmune hemolytic anemia and they may also be used in solid organ or hematopoietic stem cell transplantation. Therefore, we have planned an in vivo study to prove these in vitro findings.

Anti-D reagents should be chosen accordingly to the prevalence of D variants in the obstetric population.

BACKGROUND: Resolving ambiguous results of D antigen typing is crucial for appropriate and rational administration of anti-D immunoprophylaxis and transfusion practice in obstetric population. The aim of the study was to establish selection criteria of anti-D reagents for our population. METHODS: A total of 12 689 samples from primiparous women in Split-Dalmatia County, Croatia, were typed for RhD antigen during the period of 5 years. Ambiguous results were submitted to additional serologic investigation and genotyping. RHD genotyping was performed by commercial genotyping kits (Ready Gene weak D ® and Ready gene CDE, Inno-Train, Kronberg, Germany). Relative frequencies and accompanying 95% confidence intervals were used to estimate the prevalence of variants. RESULTS: The prevalence of D variants was 0.42% (95% CI 0.31; 0.53). The most common partial D variant was D Va (RHD*05.05), with the prevalence of 0.08% (95% CI 0.03; 0.13). All weak D variants were weak D types 1, 2 and 3 (RHD*weak D type 1, RHD*weak D type 2, RHD*weak D type 3). Weak D samples were distinguishable from partial D in routine typing due to the difference in reactivity of partial D samples with clones D7B8 and RUM-1. Cell line RUM-1 gives weak or negative reactions with partial DVa category. CONCLUSION: The most common partial D variant in our population is DVa. It is recommended to use cell lines which do not strongly agglutinate DVa variant in routine RhD typing. The appropriate choice of reagents will enable the serology methods to recognize the cases in which RHD genotyping is required.

Broadened Allocation of Pancreas Transplants Across Compatible ABO Blood Types.

BACKGROUND: Current Organ Procurement and Transplantation Network (OPTN) policy restricts certain blood type-compatible simultaneous pancreas and kidney (SPK) transplants. Using the Kidney Pancreas Simulated Allocation Model, we examined the effects of 5 alternative allocation sequences that allowed all clinically compatible ABO transplants. METHODS: The study cohort included kidney (KI), SPK, and pancreas alone (PA) candidates waiting for transplant for at least 1 day between January 1, 2010, and December 31, 2010 (full cohort), and kidneys and pancreata recovered for transplant during the same period. Additionally, because the waiting list has shrunk since 2010, the study population was reduced by random sampling to match the volume of the 2015 waiting list (reduced cohort). RESULTS: Compared with the current allocation sequence, R4 and R5 both showed an increase in SPK transplants, a nearly corresponding decrease in KI transplants, and virtually no change in PA transplants. Life-years from transplant and median years of benefit also increased. The distribution of transplants by blood type changed, with more ABO:A, B, and AB transplants performed, and fewer ABO:O across all transplant types (KI, SPK, PA), with the relative percent changes largest for SPK. DISCUSSION: Broadened ABO compatibility allowances primarily benefitted SPK ABO:A and AB candidates. ABO:O candidates saw potentially reduced access to transplant. The simulation results suggest that modifying the current allocation sequence to incorporate broadened ABO compatibility can result in an increase in annual SPK transplants.

Red blood cell minor antigen mismatches during chronic transfusion therapy for sickle cell anemia.

BACKGROUND: Red blood cell (RBC) alloimmunization occurs at a high frequency in sickle cell anemia (SCA) despite serologic matching for Rh (C/c, E/e) and K antigens. RBC minor antigen genotyping allows for prediction of antigens and RH variants that may lead to alloimmunization. STUDY DESIGN AND METHODS: RBC antigen genotyping was performed on chronically transfused pediatric SCA patients, using PreciseType human erythrocyte antigen (HEA), RHCE, and RHD BeadChip arrays. All patients received C/c, E/e, and K serologically matched units (Category 1); patients with prior RBC antibodies were also matched for Fya , Jkb , and any antibodies (Category 2). The RBC genotypes of all leukoreduced (LR) units transfused over a 12-month period were determined by the prototype HEA-LR BeadChip assay. RESULTS: There were 2320 RBC units transfused to 90 patients in 1135 transfusion episodes. Thirty-five (38.9%) patients had homozygous or compound heterozygous RH variants. Seven new alloantibodies were detected, with alloantibody incidence of 0.706 in 100 units for Category 2 transfusions and 0.068 in 100 units for Category 1 (p = 0.02). Three patients on Category 2 transfusions formed new anti-Jsa and had a higher rate of exposure to Jsa than those who did not form anti-Jsa (20.4 vs. 8.33 exposures/100 units, p = 0.02). The most frequent mismatches were S (43.9%), Doa (43.9%), Fya (29.2%), M (28.4%), and Jkb (28.1%). CONCLUSIONS: Alloimmunization incidence was higher in those with prior RBC antibodies, suggesting that past immunologic responders are at higher risk for future alloimmunization and therefore may benefit from more extensive antigen matching beyond C/c, E/e, K, Fya , and Jkb .

Harnessing Scientific and Technological Advances to Improve Equity in Kidney Allocation Policies.

We reported that current assignment of HLA-DQ is a barrier to organ allocation. Here we simulated the impact of incorporating HLA-DQ antigens and antibodies as A/B and αß allelic variants, respectively, on calculated panel reactive antibody (cPRA) and probability of finding potential compatible donors (PCD). A cohort of 1224 donors and 2075 sensitized candidates was analyzed using HLA-DQαß allelic (study) versus serologic (current practice) nomenclature. A significant (p < 10-4 ) decrease in cPRA was observed with higher impact for male versus female, and first transplant versus retransplant (p < 10-4 ), affecting mostly patients with moderate cPRA (30-80%). Consequently, the number of patients qualifying for 100% cPRA points according to the United Network for Organ Sharing-Kidney Allocation System decreased by 37%. More critically, by using allelic versus serologic nomenclature for HLA-DQ, the number of PCDs for all patients was increased, with male and first-transplant patients showing a higher expansion compared with female and retransplants. Patients of blood group O showed the highest benefit. The goal of reporting unacceptable antigens is to improve accuracy of virtual crossmatching and increase the likelihood of finding immunologically compatible donors. Our simulation provides strong support for the need to re-evaluate the use of allele typing and how HLA-DQ antigens and antibodies are incorporated into allocation policies to ensure equity.

Serological weak D phenotypes: a review and guidance for interpreting the RhD blood type using the RHD genotype.

Approximately 0·2-1% of routine RhD blood typings result in a "serological weak D phenotype." For more than 50 years, serological weak D phenotypes have been managed by policies to protect RhD-negative women of child-bearing potential from exposure to weak D antigens. Typically, blood donors with a serological weak D phenotype have been managed as RhD-positive, in contrast to transfusion recipients and pregnant women, who have been managed as RhD-negative. Most serological weak D phenotypes in Caucasians express molecularly defined weak D types 1, 2 or 3 and can be managed safely as RhD-positive, eliminating unnecessary injections of Rh immune globulin and conserving limited supplies of RhD-negative RBCs. If laboratories in the UK, Ireland and other European countries validated the use of potent anti-D reagents to result in weak D types 1, 2 and 3 typing initially as RhD-positive, such laboratory results would not require further testing. When serological weak D phenotypes are detected, laboratories should complete RhD testing by determining RHD genotypes (internally or by referral). Individuals with a serological weak D phenotype should be managed as RhD-positive or RhD-negative, according to their RHD genotype.