Red Cell Antibody Screening Research Articles

Clinical Significance of Positive Red Blood Cell Antibody Screen with Inconclusive Antibody Identification

Abstract 4340 Introduction:The routine blood type and screen involves screening for unexpected antibodies, in addition to checking the ABO group and RH type. Most of these antibodies are IgM type, also known as nuisance antibodies. They are thought not to have much clinical significance. A positive antibody screen can sometimes be associated with inconclusive antibody identification. An inconclusive antibody screen is defined as test reactive for gel screen (which is a two cell screen) and no defined pattern on antibody identification panel.American Association of Blood Banking states that if an antibody screen is positive, an attempt should be made to identify the antibody and cross match for the same along with ABO and RH. If the antibody screen is negative, they recommend only ABO/RH compatibility testing to be done before transfusion. However, there is great paucity of literature regarding the scenario where the antibody screen is positive but the antibody identification (ABID) is inconclusive, to see if this has any clinical implications. This study was undertaken to review the clinical implications of a positive antibody screen with inconclusive ABID. Methods:All patients who had an antibody screen performed and the antibody identification was inconclusive during Jan 1st 2005 to Dec 31st 2010, were identified from the blood bank database of our hospital. The charts were then retrospectively screened for clinical diagnosis, antibody screen and ABID, repeat screen, blood transfusions given, if any, and occurrence of transfusion reactions. The patients were also studied for rise in hemoglobin per unit of red cell (excluding patients with active blood loss or hemolysis). Patients in the screened group who had a positive antibody identified in previous screening were excluded from the study group. The control group was composed of patients with a definite positive antibody screen with an identifiable antibody during the same period.In our institution, the patients who have a positive antibody screen get a cross match by gel technology. We use Reagent Red Blood Cells 0.8% Selectogen (Ortho clinical Diagnostics) for two-cell screen and Reagent Red Blood Cells 0.8% Resolve panel A Antigram Antigen Profile (Ortho Clinical Diagnostics) for detection and defining pattern of antibodies. Results:A total of 149 patients were identified from the blood bank database, which were included in study group. 150 controls were selected as well who had identified antibodies. Subsequently 69 (46.3%) patients from the study group had a repeat antibody screen done at a later date and out of that, 16 (23.2%) patients had a definite antibody identified and in 33 (48%) patients the repeat antibody screen was negative. In 26% the repeat screen was also inconclusive. 38 patients received transfusions in the study group and 37 in the control group. The average rise in hemoglobin per unit of red blood cell was 1.1 g/dL in the study group and same 1.1 g/dL in the control group. One patient in the study group had a transfusion reaction compared to no transfusion reactions in the control group. The transfusion reaction in was in the form of delayed hemolytic reaction in this patient who was subsequently identified to have “Jka” antibody at a later date. This would equate to 0.7% of all patients with inconclusive screen and 6% of patients who would have an antibody identified on subsequent testing. There was no mortality related to blood transfusion in either group. Conclusion:Patients who have an inconclusive ABID on antibody screen are usually ignored as having not much clinical significance. Our study indicates that although transfusion appears relatively safe in such patients, they can rarely have transfusion reactions, likely due to yet unidentified antibodies. Although 48% of patients retested will have a negative antibody screen, about a quarter of patients will have an antibody identified on subsequent testing. Hence, all patients with inconclusive ABID screen should be tested again, to identify if an antibody is present, in order to avoid any untoward reactions. Disclosures:No relevant conflicts of interest to declare.

Red blood cell antibody screening in pregnancy

Sir, Hemolytic disease of newborn (HDN) is defined as neonatal anemia and hyperbilirubinemia caused by an incompatibility between maternal and fetal red blood cells (RBCs).[1] In 98% cases it is caused due to ABO and Rh incompatibility and antibodies to other blood group antigens (Kell, c, E, C, Kidd, Duffy, M, and so on) are causative in remaining 2%.[2] More than 43 different RBC antigens have been reported to be associated with HDN.[3] Red cell antibody screening (RCAS) is a valuable tool in the detection of alloantibodies to other blood group systems (other than ABO and Rh) in the serum of patients during pregnancy or prior to transfusion. Red cell antibody identification (RCAI) should then be carried out on a larger panel of RBCs to precisely identify the antibody. In a prospective study carried out on 624 antenatal cases, RCAS was done using a 3-cell panel from Diamed, Switzerland. RCAI was carried out on cases that were positive for RCAS. RCAS was positive in 9 out of 624 cases—1.4% (excluding the 3 cases who had autoantibodies). After RCAI these were identified as anti-D antibody (6 cases, 66%), anti-D with anti-C antibody (2 cases, 22%), and anti-M antibody (1 case, 11%). The most common antibody identified remained anti-D. In 2 cases of Rh negative pregnancy, the RCAS was suggestive of anti-D. RCAI done, however, showed a combination of anti-D and anti-C. One case of anti-M was detected in a G2P1L1D1 lady. The first pregnancy was full-term normal delivery at home, however, the baby died after birth. The mother’s and baby’s blood group was O positive. RCAS done during second pregnancy was suggestive of anti-Duffy (Fya) or anti-M antibody. RCAI done showed anti-M antibody with dosage effect. The second pregnancy was postdated with Intrauterine growth retardation (IUGR,) and Lower segment caesarean section(LSCS) was done for fetal distress. The baby had hyperbilirubinemia and was Direct Coombs test (DCT) positive requiring phototherapy. Rh incompatibility continues to be a common cause for HDN. Patients with no prior history of sensitization can also develop anti-D as seen in 3 of our cases probably due to naturally occurring anti-Rh antibodies or antepartum hemorrhage. Despite the use anti-D immunization, 1%–2% of the cases are still sensitized. Anti-D immunization resulted in a favorable fetal outcome in the study. Anti-D complicated with anti-C presents with more severe HDN as seen in 1 patient who had a previous stillbirth and a hydrops baby despite receiving anti-D. Anti-C antibodies resulting in HDN requiring exchange transfusion have been reported.[4] Anti-M as a cause of HDN is rare as they are usually complete cold antibodies (IgM). However, it can be IgG type resulting in HDN.[3] HDN due to anti-M antibody can be mild to severe with stillbirth and cases requiring exchange transfusion have been reported.[5] Anti-M causing blood group discrepancy and crossmatch incompatibility has been reported in the Indian literature.[6] Antenatal detection of the non-anti-D causes of HDN requires RCAS. If RCAS is positive, the following steps are to be taken. RCAI should be done to identify the antibody. The spouse has to be screened for the presence of offending antigen and the pediatrician has to be alerted about delivery of a potentially sensitized infant. The blood bank should find a suitable antigen-negative donor for transfusion to baby and mother.

Type and screen policy in the blood bank: Is AHG cross-match still required? A study at a multispecialty corporate hospital in India

Background:Antibodies against only about 25–28 blood group antigens are known to cause hemolytic reactions (HTRs), and red cell antibody screening should detect such clinically significant antibodies. An extension of the antibody screening test is the ‘type and screen’ done to detect clinically significant antibodies, omiting the anti-human globulin (AHG) cross-match.Aim:The aim of this study was to find out if the type and screen procedure is a safe method for pre-transfusion testing when compared to the AHG cross-match currently in use in India.Materials and Methods:We evaluated data from 45373 patients for whom a total of 61668 units of packed red blood cells (PRBC) were cross-matched in the AHG phase using DiaMed® ID cards. An antibody screen was carried out in all the patients using the DiaMed® ID-DiaCell I+II+III. The AHG cross-match was also carried out for all recipients, irrespective of the result of the antibody screen. The results were compared to see if there were any cases where the antibody screening was negative but the AHG cross-match showed incompatibility.Results:Not a single case was found where the antibody screen was negative and AHG cross-match showed incompatibility. In 68 cases the antibody screening was positive. Out of the 68 cases, AHG cross-match was incompatible with at least one unit of PRBC in 41 cases.Conclusion:The screening cell panel adequately detected the clinically significant antibodies in the Indian population in our study. The type and screen policy can be safe, efficient, cost-effective, and beneficial to the transfusion service in India.

A Randomized Trial of the Safety and Benefit of Transfusion Vs. Standard Care In the Prevention of Sickle Cell-Related Complications In Adults: a Preliminary Report From the Phase II NHLBI Comprehensive Sickle Cell Centers (CSCC) Study of Neuropsychological Dysfunction and Neuroimaging Abnormalities In Neurologically Intact Adult Patients with Sickle Cell Disease

AbstractAbstract 3221 Background:Most adult sickle cell anemia patients have received transfusion therapy. However, prospective studies evaluating the efficacy of transfusions in preventing sickle cell-related complications are lacking. The Phase II Neuropsychological Adult Sickle Cell Anemia Study is a randomized trial of chronic transfusion vs. standard of care in patients with abnormal neurocognitive function in order to determine the safety and benefits of transfusion therapy on neurocognitive function. A secondary goal of the study is to evaluate the benefit of chronic transfusion on the frequency and severity of acute sickle cell events; this is a preliminary report of this specific aim. Methods:Eligibility required normal neurological exam, WAIS III PIQ score ≤ 90, hemoglobin ≤ 9 g/dL, hemoglobin SS electrophoresis, and age between 21 and 55 years. Patients were randomly assigned to receive either standard care or transfusions. The transfusion goal was to maintain a hemoglobin of 2 g/dL rise over baseline with matched red cells for D, C/c, E/e, and Kell antigens. The protocol required simple transfusions at approximately 4 week intervals. Chelation therapy was not part of the study design. Patients underwent serial clinical and laboratory evaluations with central analysis of all clinical and transfusion events and complications. Laboratory testing of subjects in the transfusion arm included quantitative hemoglobin S/A, hemoglobin concentration, ferritin levels, and red cell antibody screening; a full hematology/chemistry panel was performed for all subjects at baseline, the study mid-point, and at the end of the study. Results:There were 20 patients in the transfusion arm (TX arm) with a mean age of 29 years vs. 16 patients in the standard care arm (SC arm) with a mean age of 30.5 years. The baseline data in the TX arm was similar to the SC arm: hemoglobin 7.8 vs. 8.0 g/dL; hematocrit 22.6% vs. 23.1%; hemoglobin F 10.5% vs. 12.5%. Thirty-five percent of patients randomized to the TX arm had a history of acute chest syndrome (ACS) vs. 31% in the SC arm; 30% of patients in the TX arm were on hydroxyurea compared to 50% in the SC arm. The TX arm patients have received an average of 5.6 transfusions (2 units per transfusion) with only one subject requiring an acute transfusion (5%); in contrast, 4 SC arm patients (25%) were transfused for acute events for a total of 7 units (average 1.8 per patient). The transfusion therapy improved the average hematologic status of patients: hemoglobin S% decreased from 85% to 32% (p=0.0003); hemoglobin and hematocrit increased from 7.6 to 9.4 g/dL (p=0.0052) and 22% to 28%, (p=0.007), respectively. Bilirubin declined from 3.6 to 2.4 mg/dL (p=0.042). In contrast, only bilirubin showed a significant decrease in the SC arm. In the TX arm, serum ferritin rose an average of 1318 to 2368 (p=.001); there was no change in liver function. There were no clinical transfusion reactions in the 120 study transfusions (360 units); however, one patient on routine screening reported a transient anti-D antibody without clinical or laboratory changes. Clinical Results:Adverse events were higher in the SC arm. Total number of adverse events in the TX arm were 23 (1.2 per person) vs. 66 in (4.1 per person) in the SC arm. There were 5 hospitalizations in the TX arm and 21 in the SC care arm, with a median number of hospitalized days per hospitalization of 5.0 and 6.0 respectively. The total number of serious events was 6 in the TX arm (0.3 per person) vs. 23 in the SC arm (1.4 per person). The total number of vaso-occlusive events in the TX arm were 14 (0.7 per person) vs. 57 (3.6 per person) in the SC arm. Acute pulmonary events occurred in 25% (4 patients) of the SC arm vs. none in the TX arm. Conclusions:This is preliminary data from the first prospective randomized study of the safety and efficacy of transfusion therapy in adults with SCD. We demonstrate the safety of transfusion therapy. Compared to standard therapy, transfusions improve or stabilize critical laboratory markers, decrease serious sickle cell anemia-related adverse events, and decrease in hospitalizations. Increase in ferritin is an expected outcome in transfused patients since chelation was not a part of this transfusion protocol. On completion of the study, the potential benefits of transfusion therapy on sickle cell disease morbidity including neurocognitive function will be reported. Disclosures:Field:Novartis Pharm: Honoraria.

Fréquence de l’allo-immunisation érythrocytaire chez les malades polytransfusés au centre hospitalo-universitaire du Point G, Bamako, Mali

This prospective study conducted within 9 months period aimed to determine the frequency of red cell alloimmunization among polytransfused patients of the medical Hematology and oncology ward, and the unit of hemodialysis of the Nephrology ward at the Point-G hospital. Irregular red blood cell antibody screening and identification were performed by gel-filtration method using indirect antiglobulin test and enzymatic treated cells. We did not use saline medium. A total of 78 patients were included in this study. The mean age of the patients was 36.78 ± 14.73 years (range: 11 and 77 years). The sex ratio was of 1.11 in favour of the women. The mean blood units transfused were 12.21 ± 9.99 units (range: 4 and 45 units). The Rhesus phenotypes Dccee, DccEe and DCcee were most predominant, with the respective frequencies of 67.9, 15.4 and 10.3%. Kell antigen was found at a frequency of 1.28%. The total rate of red cell alloimmunization was 10.3%. There was no significant difference between the two wards. All the screened agglutinins were warm antibodies belonging to the Rhesus system: anti-E (7.7%), anti-C (1.3%) and anti-D (1.3%). Only Anti-E was present among hematologic patients. We did not find a significant link between the sex, the age, the number of blood units transfused and the positivity of the antibody screening. We conclude that the frequency of post-transfusional alloimmunization is high among polytransfused patients in Mali. A systematic antibody screening among these patients and the selection of red cells with known Rhesus/Kell phenotypes would allow an optimal blood transfusion safety.

Polyethylene glycol antiglobulin tube versus gel microcolumn: influence on the incidence of delayed hemolytic transfusion reactions and delayed serologic transfusion reactions

Our institution has reported on delayed hemolytic transfusion reaction (DHTR) and delayed serologic transfusion reaction (DSTR) incidence changes. From January 1993 to June 2003, a polyethylene glycol (PEG) tube-based technique was used for red blood cell (RBC) antibody screen. In June 2003, a gel microcolumn technique was implemented. Impact of this on antibody detection and DHTR and DSTR incidence was investigated. Positive antibody screen frequency and antibody specificity from January 2002 to March 2003 and July 2003 to September 2004 were compared. Overall incidence of DHTR and DSTR as well as the number and identity of the RBC antibodies implicated from August 1999 through June 2003 (PEG) and July 2003 through July 2007 (gel) were compared. The mean length of hospital stay (LOS) and number of RBC units transfused per patient were compared. Equivalent numbers of antibody screens were performed with equivalent numbers of positive screens. Significant differences were not seen in the detection of clinically significant antibodies but significantly fewer clinically insignificant antibodies were detected with gel. Ninety-six DHTRs and DSTRs were diagnosed. The LOS and number of transfused RBC units were not statistically different. A significantly higher incidence of DHTRs and DSTRs was seen with PEG compared to the gel. The gel microcolumn method is similar to the PEG in detecting clinically significant antibodies but detects fewer clinically insignificant antibodies. The implementation of gel resulted in a lower incidence of DHTRs and DSTRs compared to PEG.

Risk factors for RhD immunisation despite antenatal and postnatal anti-D prophylaxis.

ObjectiveTo identify risk factors for Rhesus D (RhD) immunisation in pregnancy, despite adequate antenatal and postnatal anti-D prophylaxis in the previous pregnancy. To generate evidence for improved primary prevention by extra administration of anti-D Ig in the presence of a risk factor.DesignCase–control study.SettingNation-wide evaluation of the Dutch antenatal anti-D-prophylaxis programme.PopulationCases: 42 RhD-immunised parae-1, recognised by first-trimester routine red cell antibody screening in their current pregnancy, who received antenatal and postnatal anti-D Ig prophylaxis (gifts of 1000 iu) in their first pregnancy. Controls: 339 parae-1 without red cell antibodies.MethodsData were collected via obstetric care workers and/or personal interviews with women.Main outcome measureSignificant risk factors for RhD immunisation in multivariate analysis.ResultsIndependent risk factors were non-spontaneous delivery (assisted vaginal delivery or caesarean section) (OR 2.23; 95% CI:1.04–4.74), postmaturity (≥42 weeks of completed gestation: OR 3.07; 95% CI:1.02–9.02), pregnancy-related red blood cell transfusion (OR 3.51; 95% CI:0.97–12.7 and age (OR 0.89/year; 95% CI:0.80–0.98). In 43% of cases, none of the categorical risk factors was present.ConclusionsIn at least half of the failures of anti-D Ig prophylaxis, a condition related to increased fetomaternal haemorrhage (FMH) and/or insufficient anti-D Ig levels was observed. Hence, RhD immunisation may be further reduced by strict compliance to guidelines concerning determination of FMH and accordingly adjusted anti-D Ig prophylaxis, or by routine administration of extra anti-D Ig after a non-spontaneous delivery and/or a complicated or prolonged third stage of labour.

Groupes sanguins et recherche des anticorps antiérythrocytaires : analyse d’erreurs au contrôle national de qualité en 2006

Further to a survey set up in 2006 over 2600 laboratories by the French agency for health product safety (AFSSAPS), seven ABO grouping errors and 53 negative answers to red blood cell antibody screening with a serum containing anti-RH1 antibody, have been found. A questionnaire sent to the involved laboratories revealed non-analytical errors already met in previous cases. Besides, the analytical stage has also induced red blood cell antibody screening errors due to a wrong serum collection by the automat. Here are displayed the analysis of the questionnaire results and proposed corrections.

Women's attitude towards prenatal screening for red blood cell antibodies, other than RhD

BackgroundSince July 1998 all Dutch women (± 200,000/y) are screened for red cell antibodies, other than anti-RhesusD (RhD) in the first trimester of pregnancy, to facilitate timely treatment of pregnancies at risk for hemolytic disease of the fetus and newborn (HDFN). Evidence for benefits, consequences and costs of screening for non-RhD antibodies is still under discussion. The screening program was evaluated in a nation-wide study. As a part of this evaluation study we investigated, according to the sixth criterium of Wilson and Jüngner, the acceptance by pregnant women of the screening program for non-RhD antibodies.MethodsControlled longitudinal survey, including a prenatal and a postnatal measurement by structured questionnaires. Main outcome measures: information satisfaction, anxiety during the screening process (a.o. STAI state inventory and specific questionnaire modules), overall attitude on the screening program. Univariate analysis was followed by standard multivariate analysis to identify significant predictors of the outcome measures. Participants: 233 pregnant women, distributed over five groups, according to the screening result.ResultsSatisfaction about the provided information was moderate in all groups. All screen- positive groups desired more supportive information. Anxiety increased in screen- positives during the screening process, but decreased to basic levels postnatally. All groups showed a strongly positive balance between perceived utility and burden of the screening program, independent on test results or background characteristics.ConclusionWomen highly accept the non-RhD antibody screening program. However, satisfaction about provided information is moderate. Oral and written information should be provided by obstetric care workers themselves, especially to screen-positive women.

Effect of Screening for Red Cell Antibodies, Other Than Anti-D, to Detect Hemolytic Disease of the Fetus and Newborn: A Population Study in The Netherlands

Hemolytic disease of the fetus and newborn (HDFN) is a serious disorder resulting from maternal red blood cell alloantibodies directed against fetal red cells. Alloimmunization against the D antigen has been responsible for most cases of severe HDFN but, as methods of preventing D immunization have developed, alloantibodies other than anti-D, namely anti-K and anti-c in particular, have emerged as an important cause of severe HDFN. This report details the effect of a first-trimester antibody screening program instituted in the Netherlands to detect antibodies other than anti-D in a timely manner. Among 305,000 consecutive pregnancies in an 18-month period, there were 1002 with such alloantibodies. In a parallel-coverage validation study, patients with HDFN due to antibodies other than anti-D that were missed on screening were identified retrospectively. The prevalence of positive antibody screens on first-trimester screening was 1,232 per 100,000, of which 20% were not confirmed by the reference laboratory and 47% had no clinical consequences; only 7% involved anti-D antibodies. The frequency of clinically relevant alloantibodies other than anti-D was 328 per 100,000, of which 191 per 100,000 were at risk of HDFN. The most common antibodies were anti-E, followed by anti-K and anti-C. Severe HDFN resulting from immunization to antigens other than D and requiring intrauterine or postnatal transfusions developed in 21 of 567 (3.7%) of the pregnancies that were at risk; the antibodies were anti-K in 11.6%; anti-c in 8.5%; anti-E in 1.1%; and Rh antibodies other than anti-C, anti-D, or anti-E in 3.8%. All fetuses or children identified as being affected were treated promptly. Two children had complications from the transfusions; one was born at 34 weeks after 4 intrauterine transfusions, and one developed necrotizing enterocolitis after an exchange transfusion at birth. There was no mortality directly related to HDFN. The coverage validation study showed the screening program to be 75% sensitive. Five of 8 cases that were missed at screening were due to anti-C, and delay-related permanent damage occurred in 2 of the affected children; one had kernicterus and suffered permanent brain damage and one had intracerebral bleeding caused by asphyxia that was possibly related to severe antenatal anemia. Screening proved to be 99.8% specific, and its positive predictive value for detecting severe HDFN was 3.7. An estimated 15,000 pregnant women would need to be screened in order to detect one fetus at risk of severe HDFN. A single first-trimester red cell alloantibody screen detects most cases at risk of severe HDFM and would seem to be warranted as part of routine prenatal care. Its performance might be improved by repeated testing of C-negative pregnant women at week 30.

Donation testing

Donation testing

Effect of screening for red cell antibodies, other than anti‐D, to detect hemolytic disease of the fetus and newborn: a population study in the Netherlands

Hemolytic disease of the fetus and newborn (HDFN) is a severe disease, resulting from maternal red cell (RBC) alloantibodies directed against fetal RBCs. The effect of a first-trimester antibody screening program on the timely detection of HDFN caused by antibodies other than anti-D was evaluated. Nationwide, all women (1,002 in 305,000 consecutive pregnancies during 18 months) with alloantibodies other than anti-D, detected by a first-trimester antibody screen, were included in a prospective index-cohort study. In a parallel-coverage validation study, patients with HDFN caused by antibodies other than anti-D, that were missed by the screening program, were retrospectively identified. The prevalence of positive antibody screens at first-trimester screening was 1,232 in 100,000; the prevalence of alloantibodies other than anti-D was 328 in 100,000, of which 191 of 100,000 implied a risk for occurrence of HDFN because the father carried the antigen. Overall, severe HDFN, requiring intrauterine or postnatal (exchange) transfusions, occurred in 3.7 percent of fetuses at risk: for anti-K in 11.6 percent; anti-c in 8.5 percent; anti-E in 1.1 percent; Rh antibodies other than anti-c, anti-D, or anti-E in 3.8 percent; and for antibodies other than Rh antibodies or anti-K, in none of the fetuses at risk. All affected children, where antibodies were detected, were promptly treated and healthy at the age of 1 year. The coverage validation study showed a sensitivity of the screening program of 75 percent. Five of 8 missed cases were caused by anti-c, with delay-induced permanent damage in at least 1. First-trimester screening enables timely treatment of HDFN caused by antibodies other than anti-D, however, with a sensitivity of only 75 percent. A second screening at Week 30 of c- women will enhance the screening program. Severe HDFN, caused by antibodies other than anti-D, is associated with anti-K, anti-c, and to a lesser extent with other Rh-alloantibodies.

Implementation of routine screening for Kell antibodies: does it improve perinatal survival?

In 1998 a national program for first-trimester screening for red cell (RBC) antibodies in all pregnant women was implemented. The aim of our study was to assess the impact on perinatal mortality caused by Kell alloimmunization Prospectively collected data on all pregnant women referred to our center from 1988 until 2005 for intrauterine transfusion (IUT) for fetal anemia due to Kell alloantibodies were analyzed. The cohort was divided into two groups, those treated before 1998 and those treated after 1998. The primary outcome was fetal and neonatal survival. Secondary outcome variables were gestational age, fetal hemoglobin (Hb) levels at first IUT, severity of hydrops, and total number of IUTs per pregnancy. Causes for mortality were analyzed in detail. A total of 43 pregnancies were included, 18 before introduction of screening and 25 thereafter. Perinatal survival increased from 61 percent in the first period to 100 percent after introduction of screening. After 1998, fetal hydrops was generally less severe at first IUT, while gestational age and fetal Hb levels at first IUT were similar. Implementation of routine screening for Kell antibodies in pregnancy was associated with an increased referral rate for suspected fetal anemia, more timely referrals, and a higher perinatal survival rate after intrauterine treatment.

P104 Red cell antibody screening with DiaMed card and with ACT 24 semi-automatic agglutination analyser based on the detection of red cell antibodies

P104 Red cell antibody screening with DiaMed card and with ACT 24 semi-automatic agglutination analyser based on the detection of red cell antibodies

Role of enzyme‐treated cells in RBC antibody screening using the gel test: a study of anti‐RH1, ‐RH2, and ‐RH3 antibodies

The role of enzyme-treated cells (ETCs) in red blood cell (RBC) antibody screening has been the subject of controversy, and its place in the clinical routine remains to be determined. In this work, plasma samples containing anti-RH1 (anti-D; N = 10), anti-RH2 (anti-C; N = 10), or anti-RH3 (anti-E; N = 10) antibodies were studied. The samples were diluted in nonbuffered or buffered normal saline, as well as in a pool of AB plasma samples. Titers and scores were determined by means of the gel test, using the indirect antiglobulin test (IAT) as well as ETCs, with R(0)r, r'r, or r''r test cells. Our results showed that compared to the IAT, ETCs allowed a clearer detection of anti-RH2 and anti-RH3, but not of anti-RH1 antibodies. Based on our study, it is not clear whether the ETC phase of the gel test should be maintained for RBC antibody screening.

The ScanGel System Shows at least Equal Sensitivity for the Detection of Red Cell Antibodies in Comparison to the ID Micro Typing System

Objective: The aim of this study was to compare 2 testsystems for red cell antibody screening. Materials andMethods: 30 fresh and 92 stored frozen samples withknown red cell antibodies (rbc-abs) and 356 consecutiveblood samples sent in for routine serology were investigatedin parallel using 2 different test systems: the IDMicro Typing System (test system A) and the ScanGelSystem (test system B). Results: Test system B demonstrateda significantly higher sensitivity (98.4 vs. 91.0%, p= 0.019) and equal specificity (99.7 vs. 100%) comparedto test system A. Conclusion: In this study, the ScanGelSystem was at least as good as the ID Micro Typing Systemin the detection of rbc-abs. It showed a significantlyhigher sensitivity that will have to be confirmed inprospective studies and across different batches of testcells.

自動輸血検査装置ＩＤ‐ＧｅｌＳｔａｔｉｏｎの使用経験‐試験管法及びＡｕｔｏＶｕｅとの比較検討‐

We compared the ID-GelStation (GS) with Auto Vue system (AV) equipment and standard tube test (TT) with regard to ABO and Rh blood typing and red cell antibody screening in 190 samples, 59 antibody-positive sera and 71 antibodies. GS showed an equal reaction to TT and AV in ABO cell typing and Rh typing. In ABO reverse typing, GS tended to show s stronger reaction than AV but a weaker reaction than TT, with which 9 of 109 samples needed to retested.In red cell antibody screening for 71 antibodies, the papain two-stage technique of GS apparently showed stronger reaction than the bromeline one-stage technique, especially for anti-Rh antibody. Further, GS detected antibodies such as anti-Fy, anti-Jk and anti-Jr which were detectable in antiglobulin testing. GS was more sensitive for anti-Rh antibody than AV in antiglobulin testing, the most important in the present blood transfusion tests. However, GS was less sensitive than the polyethylene glycol antiglobulin test (PEG-IgG) of TT. Only 4 of 10 anti-Fy and anti-Jk could be detected, suggesting that GS and AV, in which a low ionic strength solution (LISS) is used, have lower ability to detect low titer antibodies than PEG-IgG. Use of the more sensitive PEG-IgG may be for the detection of some low titer antibodies.

Micro‐Column Affinity Test and Gel Test: Comparative Study of Two Techniques for Red Cell Antibody Screening

Abstract Background and Objectives: We describe the results of a comparative evaluation of a gel test (ID Micro Typing) and a micro‐column affinity test (MCAT, Cellbind Screen) for red cell antibody screening and identification under routine conditions. Materials and Methods: 3,000 serum samples of patients from the Mannheim University Hospital were tested in parallel by means of the gel test and the MCAT, using the low‐ionic‐strength‐saline indirect antiglobulin test and the protein G affinity technique, respectively. Test cells used were the same in all tests. In addition, we performed titration studies with all detected antibodies as well as with 59 frozen sera containing antibodies of known specificity. Results: A total of 154 antibodies (5.1%) were detected, 149 by gel test and 147 by MCAT. The overall sensitivity and specificity of the gel test was 96.8 and 96.5% and of the MCAT 95.5 and 97.2%. No significant differences between the gel test and MCAT were found when the titer scores of all 213 (fresh and frozen) antibodies were used to check the results. The mean scores for the gel test and the MCAT were 26.8 and 28.5, respectively. For anti‐Fya and anti‐Kell, a significantly higher titration score could be obtained in the MCAT, whereas anti‐Lua showed a significantly higher score with the gel test. Conclusion: For the screening of unexpected red blood cell antibodies, the MCAT is as sensitive as the gel indirect antiglobulin test. The sensitivity and specificity of the two systems are more or less the same although it seems that lgM antibodies are better detected by the gel test.

Micro–Column Affinity Test and Gel Test: Comparative Study of Two Techniques for Red Cell Antibody Screening

Background and Objectives: We describe the results of a comparative evaluation of a gel test (ID Micro Typing) and a micro–column affinity test (MCAT, Cellbind Screen) for red cell antibody screening and identification under routine conditions. Materials and Methods: 3,000 serum samples of patients from the Mannheim University Hospital were tested in parallel by means of the gel test and the MCAT, using the low–ionic–strength–saline indirect antiglobulin test and the protein G affinity technique, respectively. Test cells used were the same in all tests. In addition, we performed titration studies with all detected antibodies as well as with 59 frozen sera containing antibodies of known specificity. Results: A total of 154 antibodies (5.1%) were detected, 149 by gel test and 147 by MCAT. The overall sensitivity and specificity of the gel test was 96.8 and 96.5% and of the MCAT 95.5 and 97.2%. No significant differences between the gel test and MCAT were found when the titer scores of all 213 (fresh and frozen) antibodies were used to check the results. The mean scores for the gel test and the MCAT were 26.8 and 28.5, respectively. For anti–Fy^a and anti–Kell, a significantly higher titration score could be obtained in the MCAT, whereas anti–Lu^a showed a significantly higher score with the gel test. Conclusion: For the screening of unexpected red blood cell antibodies, the MCAT is as sensitive as the gel indirect antiglobulin test. The sensitivity and specificity of the two systems are more or less the same although it seems that IgM antibodies are better detected by the gel test.

Clinical evaluation of a solid-phase test for red cell antibody screening of pregnant women.

The aims of this study were to evaluate the results of a new solid-phase screening test for detecting atypical red cell (RBC) antibodies in a large number of pregnant women and to compare these results to the clinical outcome of the newborn. A total of 38,700 infants born in Stockholm were studied retrospectively. Of these infants, 18,500 were born to pregnant women screened with the solid-phase test. Data were collected on all newborns with a positive direct antiglobulin test (DAT) and on infants requiring an exchange transfusion or a blood transfusion. These data were correlated to the screening results for the mothers. Of 409 DAT-positive newborns, a serologic explanation for the positive DAT was found in 349. Three hundred four cases were due to ABO incompatibility between mother and child; 19 of these infants needed an exchange transfusion. Forty-two cases were due to unexpected maternal RBC antibodies; 11 of these infants were given an exchange transfusion. All 11 were identified before birth. Three other infants had DAT-positive tests due to ABO incompatibility and to unexpected maternal RBC antibodies. ABO incompatibility is a major indication for exchange transfusion in DAT-positive newborns. There was no evidence that the solid-phase screening test had failed to detect any clinically significant RBC antibodies. Finally, the results of this study do not indicate a need for routine screening of D+ women more than once during each pregnancy.