Automation in immunohematology

Evaluation of Pre-Transfusion Crossmatch Test Using Microscanner C3

A pre-transfusion crossmatch test is crucial for ensuring safe blood transfusions by identifying the compatibility between donor and recipient blood samples. Conventional tube methods for crossmatching have limitations, including subjectivity in result interpretation and the potential for human error. In this study, we evaluated the diagnostic performance of a new crossmatch test using Microscanner C3, which can overcome these shortcomings. The crossmatch test results using the method were obtained in 323 clinical samples. The sensitivity, specificity, positive predictive value, negative predictive value, and concordance rate of the crossmatch test using Microscanner C3 were 98.20%, 100.00%, 100.00%, 98.11%, and 99.07%, respectively. The diagnostic performance of the new system offers a promising alternative to conventional tube methods for pre-transfusion crossmatch testing. Microscanner C3 could also increase the automation, standardization, and accuracy of crossmatch tests. The crossmatch test using Microscanner C3 is thought to increase the efficiency and reliability in identifying blood samples suitable for transfusion, thereby improving patient safety and optimizing the use of blood products in clinical settings.

Multicenter evaluation of a high-throughput microarray platform for extensive red blood cell phenotyping and antibody screening

BACKGROUND

Blood typing and antibody screening are key elements of transfusion safety. However, available single platform, flexible, and affordable technologies are limited, especially for extended phenotyping. Microarray-based technology allows for this extended phenotyping with the flexibility of piecemeal analysis.

STUDY DESIGN AND METHODS

This study was conducted in three blood donor laboratories to determine the performance of a high-throughput microarray-based system for ABO, RH1-RH5, and KEL1 typing, ABS and extended phenotyping (RH8, KEL2&3, FY1&2, JK1, MNS3). Specimens were tested simultaneously on local platforms and on the microarray-based system. When discrepancies were identified, resolver testing were performed.

RESULTS

In total, 4862 blood samples were tested for standard phenotype, 4257 for antibody screening and 2194 for extended phenotype. Results were available for 92.12% of the samples. The overall percent agreements were: 100% for ABO, 99.8% for RH1, 99.24% for RH2-5 and 99.86% for KEL1, 93.16% for antibody screening, and 99.68% for extended phenotype.

CONCLUSIONS

This microarray-based system provides highly comparable results to current CE marked assays. The ability to continuously test 3000 microarrays in 1 day, providing simultaneously both extended RBC phenotyping and antibody detection drives laboratory efficiencies. The results of our study validate the performance of this new technology; however, the percentage of samples without results must be reduced and further analysis is required to interpret the ABS screening performances. This could constitute a real breakthrough in transfusion, making it possible in the long term, on a single platform, to carry out all the analyses necessary for the qualification of donations.

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

BACKGROUND AND AIMS

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).

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 gave consent for participation were included. All samples were consecutively tested by CTT and CAT, before and after HI (pCTT, pCAT).

RESULTS

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.

CONCLUSION

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.

Variable reactivity of Rh D antigen and its serological characterization

Background: Variation in the reactivity on Rh D typing may pose challenges in interpretation and ambiguity in further patient management.Materials and Methods: A prospective study was conducted in the department of transfusion medicine for a period of 18 months. Blood grouping was performed by fully automated equipment employing column agglutination technique. All the samples with Rh D negative or discrepant reactions were subjected to weak D testing by the antihuman globulin testing method. Samples that tested positive were categorized as serological weak D type or Variant D and were further phenotyped with Partial D typing set with 6 monoclonal anti D antisera.Results: A total of 82,824 samples were tested for Rh D type during the study period. Of the study population, 65.7% were males. On Rh D type majority were Rh D positive (93%), 6.9% were negative, and the result was discrepant in 0.1% (70) samples. The overall prevalence of variant D was 1.28% (75) of the Rh D negative population and 0.09% of the total study population. The detection rate of variant D phenotype was significantly higher by the Column agglutination technique. Upon testing with Partial D kit, the partial D variant in the majority reacted wil all the 6 antisera and hence we could not rule out DIII(60%), in rest it was inconclusive. In 43% of subjects with Rh D discrepancy 'C' antigen was found in a homozygous state.Conclusion: The introduction of partial D typing kit alone may not help in the absolute characterization of variant D. Extended serological testing and selective integration of molecular testing is the need of the hour.

Comparison between tube test and automated column agglutination technology on VISION Max for anti-A/B isoagglutinin titres: A multidimensional analysis

BACKGROUND AND OBJECTIVES

VISION Max (Ortho Clinical Diagnostics, Raritan, NJ) measures anti-A/B isoagglutinin titres using automated column agglutination technology (CAT). We compared tube test (TT) and CAT of VISION Max comprehensively, including failure mode and effect analysis (FMEA), turnaround time (TAT) and cost, and suggested modified CAT (MCAT).

MATERIALS AND METHODS

For 100 samples (each 25 for blood type A, B and O with anti-A and anti-B), anti-A/B isoagglutinin titres were measured by TT and CAT (1:2-1:1024 dilution), as well as by MCAT (with agglutination at 1:32 dilution, then perform additional testing from 1:64 to 1:1024). We assessed the agreement and correlation between TT and CAT and compared FMEA (risk priority number [RPN] score), TAT (h:min:sec) and cost (US dollar, US $) among TT, CAT and MCAT.

RESULTS

TT and CAT showed overall substantial agreement (k = 0.73) and high correlation (ρ ≥ 0.75) except blood type O with anti-A (ρ = 0.68). Compared with TT, CAT showed lower RPN scores in FMEA and similar TAT and cost (FMEA, 33,700 vs. 184,300; TAT, 15:23:00 vs. 14:26:40; cost, 1377.4 vs. 1312.4, respectively). Regarding FMEA, TAT and cost, MCAT was superior to CAT or TT (43,810; 13:28:00; 899.2, respectively).

CONCLUSION

This is the first multidimensional analysis on VISION Max CAT for measuring anti-A/B isoagglutinin titres. The results of anti-A/B isoagglutinin titres by CAT were comparable with those of TT. MCAT would be a safe, time-saving and cost-effective alternative to TT and CAT in high-volume blood bank laboratories.

Evaluation of Erythrocytes Magnetized Technology for Measurement of ABO Isoagglutinin Titers

Background  A variation in the measurement of ABO antibody titer has been seen among different laboratories due to lack of standardization. In our study, we aim to evaluate automated ABO isoagglutinin titer measurements by erythrocytes magnetized technology (EMT) and compare with conventional tube technique (TT).

Methods  We performed ABO isoagglutinin titration on samples received in a reference laboratory during a period of 2 months. A total of 134 tests for immunoglobulin G (IgG) titer and 116 for immunoglobulin M (IgM) for anti-A or anti-B were included in the study. Samples were processed for ABO isoagglutination titers by both TT and EMT by QWALYS-3 (DIAGAST, France). Microsoft Excel was used to compile data, for all calculations, and to draw graphs and plots. The number and percentage of cases within ±1, ±2, or ±3 titer difference (TT-EMT) were calculated.

Results  Median titers and their ranges obtained by EMT were higher or equal to those by TT for all IgM and IgG ABO-antibodies in all blood group (BGs), except anti-A IgM in (BG) O that was lower by EMT (32 [4:128]) than TT (48 [8:256]). One twenty one (121/134, 90.3%) cases of IgG titer showed an agreement by both methods (within ± one titer difference). One hundred seven cases (107/116, 92.2%) for IgM titer were within one titer difference by both the methods.

Conclusion  Results of titration by EMT-based automated instrument QWALYS-3 and conventional TT may vary by one titer dilution in the majority of cases. Use of consistent method for patient management is, therefore, advised.

An unusual case of anti-D detection in two consecutive D+ patient samples: Antibody carryover on an automated gel platform

BACKGROUND

Laboratory results can be affected by sample to sample carryover. Carryover of different analytes occurring in automated clinical chemistry, immunology, hematology, and molecular laboratories is well described. However, carryover in a transfusion service laboratory is not reported in medical literature.

MATERIALS AND METHODS

Immunohematology testing results, demographic data, and clinical data were reviewed on three patients retrospectively from 2015 to 2019.

RESULTS

Type and screen samples tested on automated gel platform from two D+ patients were affected by anti-D carryover from a patient sample with a very high-titer anti-D. Additional immunohematology and molecular testing confirmed that anti-D in samples of two D+ patients was due to carryover.

CONCLUSION

A case of anti-D carryover caused false detection of anti-D in two D+ patients. Carryover can have implications for patient management. Transfusion laboratory staff need to be aware of it and investigate any unexpected results further.

Investigation of risk factors associated with erythrocyte engraftment after ABO-incompatible hematopoietic stem cell transplantation

ABO-incompatible hematopoietic stem cell transplantations (HSCTs) are widely practiced; however, the delay in erythrocyte engraftment can be problematic. While erythrocyte engraftment is usually indicated by an increase in reticulocyte levels without the need for erythrocyte transfusions, the disappearance of recipient-derived anti-A/B isoagglutinin and detection of donor-derived A/B antigens can also be used as other parameters. We conducted a retrospective analysis of 68 ABO-incompatible HSCTs, focusing on major and bidirectional mismatch. We analyzed known clinical risk factors associated with delayed erythrocyte engraftment using the three parameters (disappearance of anti-A/B isoagglutinin in recipient, detection of donor-derived A/B antigen, and reticulocyte levels >1%). Although the three parameters were well correlated, the results showed heterogeneity when analyzing the associated risk factors for delayed erythrocyte engraftment. In the analysis of all cases, the requirement for an HLA-matched platelet transfusion was a common risk factor. Furthermore, erythrocyte engraftment was slower in adults than in children. In adults, cytomegalovirus antigenemia was a risk factor for two parameters; however, in children, underlying disease was a common risk factor for all parameters. There is a complex relationship between erythrocyte engraftment and various factors related to HSCTs. Our results suggest that greater accuracy is possible by using analysis methods other than the measurement of reticulocyte levels.

Comparative evaluation of DTT treated ABO isoagglutinin titres performed by two methods with solid phase red cell adhesion (SPRCA) titres

BACKGROUND AND AIMS

Measurement of actual concentration of IgG requires methods like treatment of serum with dithiothreitol (DTT). This study was aimed at comparing of DTT treated ABO titres performed by conventional test tube technique (CTT) and column agglutination technique (CAT) with HA/SPRCA.

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 gave consent for participation were included. All samples were tested by CTT and CAT before and after DTT treatment (pCTT, pCAT) and with HA/SPRCA.

RESULTS

A total of 300 donors were included; 100 each from A, B and O blood group donors. Group O titres were higher than group A/B titres. Group O titres were highest when performed by pCAT, followed by pCTT and lowest by HA/SPRCA. Group A/B titres were highest when performed by HA/SPRCA, followed by pCAT and pCTT for anti-A and highest when performed by pCAT, followed by HA/SPRCA and lowest by pCTT for anti-B.

CONCLUSION

Results obtained by pCAT were closer to results obtained by pCTT, whereas those obtained by HA/SPRCA were variable. SPRCA offers the advantage of automation, no inter-observer variation and less time consumption because IgM interference is not observed with SPRCA, thus providing an alternative to pCTT. However, these methods cannot be used interchangeably and to discern the most suitable method, a clinical impact of these results needs to be studied.

An exploration of the advantages of automated titration testing: low inter-instrument variability and equivalent accuracy for ABO and non-ABO antibody titres relative to tube testing

BACKGROUND AND OBJECTIVES

Obtaining IgM and IgG titres is important in numerous clinical situations, including solid-organ transplant, obstetrics, and for testing of out-of-group plasma-containing components. Tube method is the most prevalent testing modality, though it is both labour-intensive and known for intra- and inter-laboratory variability. The utility of automated gel testing as a method to improve both inter- and intra-laboratory reproducibility is unknown.

MATERIALS AND METHODS

Two academic centres participated in a study evaluating automated gel titreing. Group O plasma samples were used to measure titres of antibodies against ABO (IgM) with buffered gel cards and 4 minor and minor red-blood-cell antigens (IgG) anti-IgG gel cards. Multiple ORTHO VISION automated analyzers were used to assess inter-instrument variation. A subset of ABO (IgM) samples were compared between laboratories to evaluate inter-laboratory variability. Multiple samples were titred by tube and by automated gel technology to determine similarity of results.

RESULTS

Testing demonstrated no significant difference between analysers or between sites when performing automated titrations (P ≥ 0·99). Non-ABO IgG titres were evaluated and demonstrated little inter-instrument variability. The IgM anti-A and -B titres obtained by automated gel testing were neither consistently higher nor lower than tube titres. Greater than 90% of titre values were within one dilution.

CONCLUSION

Based on this study, our data suggest that titreing by automated gel testing is both highly reproducible (IgM and IgG) and does not differ significantly from manual tube testing results of direct agglutination (IgM).

Performance and reliability of a benchtop automated instrument for transfusion testing: a comparative multicenter clinical study in the US population

BACKGROUND

Heavy workload in hospital transfusion services and blood centers necessitates the implementation of automated platforms. We evaluated the performance of Erytra Eflexis (Diagnostic Grifols), a recently developed midsize automated instrument for pretransfusion testing, in comparison with a US Food and Drug Administration (FDA)-cleared device (Erytra). Reproducibility and repeatability of the results were also investigated.

STUDY DESIGN AND METHODS

Studies were conducted using the same card technology and reagents at three US sites. Tests were performed on 9174 specimens from hospital patients (55.61%) and blood donors (43.39%). Evaluations included 18,413 ABO/D/reverse typing; 9084 Rh phenotypes, 4640 K phenotypes, 2052 antibody screenings, 1232 antibody identifications, 469 direct antiglobulin tests, 612 IgG crossmatches, and 700 ABO-compatibility crossmatches. A reference blood panel was also sent to each center, for a total of 3900 replicate tests. Concordance between results with the two instruments and performance among the different centers were statistically evaluated.

RESULTS

Agreement between instruments was 99.84% for 37,202 test results, with 61 discrepancies (0.16%). Percentages of positive and negative agreement were 99.82% and 99.85%, respectively. No discrepancies were observed in 12,276 tests for direct ABO/D grouping. Discrepancies were observed during antibody identification (n = 19), antibody screening (n = 15), and reverse grouping (n = 10). Investigations of the discrepancies were resolved in favor of the study instrument in 55.73% of the cases. Erytra Eflexis obtained the expected results in the reproducibility analysis.

CONCLUSION

This multicenter study demonstrates that Erytra Eflexis with its gel card technology and reagents is reliable and substantially equivalent to the FDA-cleared instrument used as the reference.

Red Cell Alloantibody Screening: Comparative Analysis of Three Different Technologies

Background

The detection of irregular antibody is a critical issue in the management of red blood cell transfusion according to the Type & Screen (T&S) practice. In order to implement the T&S procedure at our blood bank, we compared three different automated analyzers based on column agglutination technique (CAT) or solid phase red cell adherence assay (SPACA) methods.

Methods

Pre-transfusion antibody screening was performed in 986 patients candidate to elective surgery at low risk for red blood cell transfusion. We tested the following kits: the three-cell panel micro-CAT system ID-DiaCell I-II-III (DiaMed), the four-cell panel solid-phase system Capture-R Ready Screen-4 (Immucor), and the four-cell panel micro-CAT system Serascan Diana-4 (Grifols). Positive results were further investigated using corresponding identification panels, and discrepant results were investigated with all the antibody identification systems.

Results

Among 986 samples, we observed 967 concordant negative results (98.1%), 8 concordant positive results (0.8% of cases), and 11 discrepant results (1.1%). Among discrepant samples, an alloantibody could been identified in two patents (anti-M, detected by Serascan Diana-4 and ID-DiaCell I, II, III; anti-Kp^a, detected by Capture-R Ready Screen-4 and Serascan Diana-4).

Conclusion

Among the evaluated technologies, the four-cell panel micro-CAT system displayed the highest sensitivity and specificity with an optimal negative predictive value. These features might be relevant to the routine implementation of the T&S transfusion strategy.

Turnaround Time for Red Blood Cell Transfusion in the Hospitalized Patient: A Single-Center "Blood Ordering, Requisitioning, Blood Bank, Issue (of Blood), and Transfusion Delay" Study

Background and Aim:

The turnaround time (TAT) for blood transfusion (BT) is an important quality indicator for the health-care institutions undertaking this procedure. There is no established national or international benchmark for this TAT due to the dearth of a published literature. We thus studied the TAT and the contributory procedures leading to delay in commencing a red blood cell transfusion in the hospitalized patient.

Materials and Methods:

Delay was captured for the blood order transcription, requisitioning and sampling by the nurse, blood bank (BB) processing, blood issue, and the transfusion commencement in the hospitalized patients. The study was done prospectively over a 1-year period and involved all the patient locations spread over six floors in a tertiary care accredited hospital.

Results:

A total of 2022 blood requests were analyzed during the study period. Most (73%) of the blood requests were marked as urgent by the treating unit. The average time from ordering to initiation of BT was 135 min in our study. BB processes (compatibility testing and issue) comprised approximately 47% of this delay (63 min), while rest of the delay happened in the processes (ordering 13 min, sample transport 34 min, and BT commencement 25 min) outside the BB (72 min).

Conclusion:

Majority of the delay for blood transfusion happens due to the processes outside blood bank premises. Understanding the steps where delay happens has the potential to reduce the turnaround time for lifesaving procedures such as blood transfusion in the hospitalized patients.

Prevalence of irregular red cell antibody in healthy blood donors attending a tertiary care hospital in North India

BACKGROUND:

Alloantibodies may be detected in blood donors who have either been transfused previously or female donors with previous obstetric events. These antibodies can occasionally cause severe transfusion reaction, if a large amount of plasma or whole blood is transfused, as in massive transfusions and pediatric patients.

AIMS:

The present study aims to assess the prevalence of red cell antibodies in healthy blood donors at a tertiary care hospital-based blood bank in India.

MATERIALS AND METHODS:

A total of 82,153 donor samples were screened for irregular red cell antibodies between January 2012 and December 2015 at the Department of Transfusion Medicine, Indraprastha Apollo Hospitals, New Delhi. Antibody screening was performed by solid phase method using Immucor Capture–R ready screen (pooled cells) on fully automated immunohematology analyzer Galileo Neo (Immucor Inc., Norcross, GA, USA). Positive tests were further confirmed using Capture-R ready screen (4 cell panel). Advanced investigations to identify the antibody/ies were performed on confirmed positive samples. Antibody identification was conducted using various cell panels (Immucor Capture-R Ready-ID, Panocell-10, Ficin Treated). An advanced technique such as adsorption and elution was performed as per requirement.

RESULTS:

Screening with pooled cells and 4 cell panel was positive in 227 donors (0.27%), 150 of these donors had autoantibodies, 1 had autoantibodies with underlying alloantibody anti-Jk^a (0.001%), and 76 had alloantibodies (0.09%) alone in their plasma. Anti-M was the most common antibody (43 donors) identified, followed by anti-D (21 donors). Anti-N was detected in 4; anti-Jk^a, anti-C, and anti-E in two donors each followed by anti-P1 and anti-Le^b in 1 donor.

CONCLUSION:

Antibodies against red cells can be present in healthy donors detection of which is important in providing safe blood to the patient. The prevalence of red blood cell antibody in healthy donors in this study was found to be 0.27%, while the prevalence of alloantibodies was 0.09%. The majority of alloantibodies were anti-M (56.57%) and anti-D (27.63%).

Comparison of micro column technology with conventional tube methods for antibody detection

BACKGROUND AND OBJECTIVES

Conventional tube technique (CTT) has been the mainstay for antibody detection in pretransfusion testing. There have been rapid technological advances in blood banking and methodology of crossmatch has been modified to improve the sensitivity of these tests and to enable automation. This study was done to compare the efficacy of three crossmatch techniques: CTT, tube low-ionic-strength-saline indirect antiglobulin test (tube LISS-IAT), and micro column technology (MCT) used in the blood bank serology laboratory.

MATERIALS AND METHODS

In this prospective study, 150 samples from patients who had received two or more transfusions on two different occasions (with at least 72 h between two transfusions) were subjected to cross match by three different techniques - CTT, LISS-IAT, and MCT.

RESULTS

A total of 16 cases with antibodies were identified in 150 patients. Out of 16 cases, 14 were clinically significant (anti-c = 5, anti-K = 4, anti-E = 2, anti-S = 2, anti-Jka = 1) and 2 nonclinically significant antibody cases (anti-Lea). MCT detected all the 14 clinically significant antibody cases and no case of nonclinically significant antibody. Tube LISS-IAT detected 14 antibody cases including 2 cases of non-clinically significant antibody but failed to detect 1 case of anti-c and the only case of anti-Jka. CTT detected only 10 antibody cases including 2 cases of non-clinically significant antibody and but failed to detect 3 cases of anti-c, 1 case of anti-K, 1 case of anti-E, and the only case of anti-Jka.

CONCLUSION

MCT was found to be most efficacious when compared to CTT and tube LISS-IAT in detecting clinically significant red cell antibodies; although MCT missed 2 cases of Lea antibody which were detected by CTT and LISS-IAT.

Passenger Lymphocyte Syndrome (PLS): A Single-center Retrospective Analysis of Minor ABO-incompatible Liver Transplants

Background and Aims: Due to the shortage of donor livers, minor ABO-incompatible liver transplantations are commonly performed. Together with the allograft, immunocompetent B-lymphocytes, called passenger lymphocytes, are transplanted. In case of minor ABO-incompatibility, these passenger lymphocytes produce antibodies directed towards the recipient's red blood cells, which causes immune-mediated hemolysis, also known as the passenger lymphocyte syndrome (PLS). Although this is a self-limiting disorder, serious complications can occur, including graft failure. Retrospectively, we evaluated the role of PLS in minor ABO-incompatible liver transplantations performed at our center. Methods: A retrospective analysis was conducted for all minor ABO-incompatible liver transplantations performed at the Antwerp University Hospital between 2003 and 2015. All patient files were inspected for clinical and laboratory findings. In cases of PLS diagnosis, the applied treatment was also studied. Results: In total, 10 patients underwent a minor ABO-incompatible liver transplantation and 4 showed signs of PLS. All 4 PLS patients were treated with different therapeutic strategy, corresponding to the severity of hemolysis. In all 4 cases, PLS resolved following treatment. Conclusion: When performing minor ABO-incompatible liver transplantations, knowledge of PLS is elemental. Next to a high index of clinical suspicion, we suggest routine screening for markers of hemolysis, with emphasis on haptoglobin level and direct antiglobulin test, weekly in the first 4 weeks post-transplantation as well as in case of a sudden hemoglobin drop within the first 3 months after transplantation. Peri- and postoperative transfusion support using donor-compatible blood has been suggested to prevent the occurrence or limit the extent of hemolysis.

Multi-Center Evaluation of the Automated Immunohematology Instrument, the ORTHO VISION Analyzer

BACKGROUND

ORTHO VISION Analyzer (Vision), is an immunohematology instrument using ID-MT gel card technology with digital image processing. It has a continuous, random sample access with STAT priority processing. The efficiency and ease of operation of Vision was evaluated at 5 medical centers.

METHODS

De-identified patient samples were tested on the ORTHO ProVue Analyzer (ProVue) and repeated on the Vision mimicking the daily workload pattern. Turnaround times (TAT) were collected and compared. Operators rated key features of the analyzer on a scale of 1 to 5.

RESULTS

A total of 507 samples were tested on both instruments at the 5 trial sites. The mean TAT (SD) were 31.6 minutes (5.5) with Vision and 35.7 minutes (8.4) with ProVue, which renders a 12% reduction. Type and screens were performed on 381 samples; the mean TAT (SD) was 32.2 minutes (4.5) with Vision and 37.0 minutes (7.4) with ProVue. Antibody identification with eleven panel cells was performed on 134 samples on Vision; TAT (SD) was 43.2 minutes (8.3). The installation, training, configuration, maintenance and validation processes are all streamlined to provide a short implementation time. The average rating of main functions by the operators was 4.1 to 4.8. Opportunities for improvement, such as flexibility with editing QC results, maintenance schedule, and printing options were identified. The capabilities to perform serial dilutions, to accept pediatric tubes, and review results by e-Connectivity are enhancements over the ProVue.

CONCLUSIONS

Vision provides shorter TAT compared to ProVue. Every site described a positive experience using Vision.

Antibody titers in Group O platelet donors

BACKGROUND AND OBJECTIVES

The occurrence of hemolysis due to transfusion of ABO plasma-incompatible platelets (PLTs) is challenging. There has been no consensus for critical antibody titers in the transfusion community. This study was conducted to understand the trends of anti-A and anti-B antibody titer levels in O group donors and to identify any specific patterns of distribution in relation to age and gender.

MATERIALS AND METHODS

A total of 1635 Group O PLT donors were randomly selected for this prospective study. Serial 2-fold doubling dilutions were prepared for each sample to calculate the titer of anti-A and anti-B in a standard 96 well micro-plate. Tube technique was used for comparison with the microplate method for 100 samples.

RESULTS

Out of 1635 donors, 1430 (87.46%) were males and 205 (12.54%) were females. The median titer for anti-A and anti-B was 128 with range from 4 to 2048. Spearman's correlation coefficient for microplate versus tube technique was estimated to be 0.803 (P < 0.01, two-tailed). 57.12% and 51.19% of all donors had titers ≥128 for anti-A and anti-B, respectively. The geometric mean of anti-A and anti-B was 155.7 and 137.28, respectively. The titers were significantly higher (P < 0.001) in female donors. An inverse relation between titer levels and age was seen.

CONCLUSION

Microplate can be used to perform titers in resource-constrained settings. Screening for critical titers in O group donors is essential as they are more implicated in hemolytic transfusion reactions. In the absence of a global consensus on this topic, institutes may need to formulate their own guidelines on handling ABO plasma-incompatible PLT transfusions.

Comparative Analysis of Clinical Samples Showing Weak Serum Reaction on AutoVue System Causing ABO Blood Typing Discrepancies

Background

ABO blood typing in pre-transfusion testing is a major component of the high workload in blood banks that therefore requires automation. We often experienced discrepant results from an automated system, especially weak serum reactions. We evaluated the discrepant results by the reference manual method to confirm ABO blood typing.

Methods

In total, 13,113 blood samples were tested with the AutoVue system; all samples were run in parallel with the reference manual method according to the laboratory protocol.

Results

The AutoVue system confirmed ABO blood typing of 12,816 samples (97.7%), and these results were concordant with those of the manual method. The remaining 297 samples (2.3%) showed discrepant results in the AutoVue system and were confirmed by the manual method. The discrepant results involved weak serum reactions (<2+ reaction grade), extra serum reactions, samples from patients who had received stem cell transplants, ABO subgroups, and specific system error messages. Among the 98 samples showing ≤1+ reaction grade in the AutoVue system, 70 samples (71.4%) showed a normal serum reaction (≥2+ reaction grade) with the manual method, and 28 samples (28.6%) showed weak serum reaction in both methods.

Conclusions

ABO blood tying of 97.7% samples could be confirmed by the AutoVue system and a small proportion (2.3%) needed to be re-evaluated by the manual method. Samples with a 2+ reaction grade in serum typing do not need to be evaluated manually, while those with ≤1+ reaction grade do.

Evaluation of Magnetized-Erythrocyte Group Antigens to Detect ABO Antibodies

Screening for IgM titers of anti-A and anti-B is recommended when providing ABO incompatible platelet transfusion. The life-time of reagent cells depends upon the preservative diluents. We aimed to evaluate the IgM titers of anti-A and anti-B testing with magnetized-erythrocyte group antigens (MEGA) and fresh RBCs and study the relationship of ABO antibody titers between both techniques. Altogether, 100 serum samples from group O donors at the National Blood Centre, Thai Red Cross Society, Bangkok, Thailand were included. EDTA blood from three different A and B blood group individuals was prepared as fresh reagent RBCs and MEGA. Each serum sample was tested simultaneously for IgM anti-A and anti-B titers using fresh RBCs and MEGA by standard tube technique. Antibody titers were compared between both techniques. Test for reproducibility and stability of MEGA were performed. The IgM anti-A and anti-B titers using fresh RBCs yielded higher agglutination scores than MEGA (P < 0.001). However, a good correlation was obtained in the agglutination titers (anti-A, r = 0.838 and anti-B, r = 0.877). The mean and standard deviation of anti-A and anti-B titers using MEGA from five sera in triplicate showed no significant difference (P > 0.05). Moreover, the titer test results using MEGA after dilution remained stable up to 8 h. The MEGA can be used as a replacement for fresh RBCs to perform ABO serum grouping. It is simple to use, avoids centrifugation and provides good results in terms of stability and reproducibility.

Comparison Between Conventional and Automated Techniques for Blood Grouping and Crossmatching: Experience from a Tertiary Care Centre

Context:

The routine immunohematological tests can be performed by automated as well as manual techniques. These techniques have advantages and disadvantages inherent to them.

Aims:

The present study aims to compare the results of manual and automated techniques for blood grouping and crossmatching so as to validate the automated system effectively.

Materials and Methods:

A total of 1000 samples were subjected to blood grouping by the conventional tube technique (CTT) and the automated microplate LYRA system on Techno TwinStation. A total of 269 samples (multitransfused patients and multigravida females) were compared for 927 crossmatches by the CTT in indirect antiglobulin phase against the column agglutination technique (CAT) performed on Techno TwinStation.

Results:

For blood grouping, the study showed a concordance in results for 942/1000 samples (94.2%), discordance for 4/1000 (0.4%) samples and uninterpretable result for 54/1000 samples (5.4%). On resolution, the uninterpretable results reduced to 49/1000 samples (4.9%) with 951/1000 samples (95.1%) showing concordant results. For crossmatching, the automated CAT showed concordant results in 887/927 (95.6%) and discordant results in 3/927 (0.32%) crossmatches as compared to the CTT. Total 37/927 (3.9%) crossmatches were not interpretable by the automated technique.

Conclusions:

The automated system shows a high concordance of results with CTT and hence can be brought into routine use. However, the high proportion of uninterpretable results emphasizes on the fact that proper training and standardization are needed prior to its use.