Isohemagglutinin titration in pooled and apheresis platelets

BACKGROUND

Platelet inventory constraints necessitate ABO-incompatible platelet transfusion. Many minimize the hemolytic impact by confirming low titre (LT) donor isohemagglutinins. This process is costly. Pathogen-reduced platelets (PRP) in platelet additive solutions (PAS) will dilute plasma and decrease high-titre isohemagglutinins (HT). We determined the proportion of HT platelets and incompatible transfusions for units suspended in plasma to reassess the need for titres following introduction of PRP/PAS.

STUDY DESIGN AND METHODS

Our titre method is manual tube (1:50) dilution of platelet supernatant from apheresis or whole blood derived buffy coat pools suspended in plasma, tested with A1/B red cells. Testing included 49,058 pooled and 11,738 apheresis platelets over 4 years. The HT proportion, rate of out-of-group transfusions, and hemolytic reactions were determined. The impact of PAS dilution was estimated.

RESULTS

Totally 60,796 platelet units were tested. Group O pooled and group B apheresis platelets had HT in 6.6% and 5.7%, respectively. Group A pooled and apheresis platelets included 2% with HT. Approximately 25% of platelets transfused were ABO-incompatible and no hemolytic reactions were reported. Based on the proportions of PAS-E and plasma for PRP platelets, plasma from each donor comprises 11 mL (6% of total volume) vs 20-257 mL in untreated pools. PAS-E will replace and dilute residual plasma by at least 50%.

DISCUSSION

Rare platelet pools may demonstrate HT. PRP platelets with PAS will reduce titres and may abrogate the need for titration. A strategy of group specific transfusion or transfusion of group A PRP platelet transfusions may be a safe alternative.

Modification of deglycerolization procedure improves processing and post-thaw quality of cryopreserved sickle trait red cell concentrates

Red blood cell (RBC) transfusion is a critical therapy for those with sickle cell disease (SCD). Alloimmunization is frequent for those with SCD and may limit the availability of matched RBC. Cryopreserved RBCs, from family members or donors with a similar RBC antigen profile could provide a viable alternative to avoid further alloimmunization and prevent hemolytic transfusion-related events. However, cryopreserved SCD and Sickle Cell trait (S-trait) donor RBC units suffer from reduced recovery following deglycerolization. This study proposes and tests a modified deglycerolization protocol using an automated cell processor to mitigate RBC loss. Six red cell concentrates (RCC) from donors with S-trait and six control RCCs were glycerolized, frozen (<-65 °C) and deglycerolized on the ACP 215 using modified parameters (decreased hypertonic solution flow rate (100 mL/min) and hypertonic equilibration delay (120 s), and increased NaCl dilution volumes (500 mL). Quality testing included: hematocrit (HCT), hemolysis, indices, extracellular potassium, morphology, osmotic fragility, osmotic gradient ektacytometry, hemoglobin (HGB), and recovery. Canadian standards (CS) indicate that acceptable deglycerolized units for transfusion require a HCT ≤0.80 L/L, HGB ≥35 g/unit, and hemolysis <0.8 % in 90 % of units tested. No significant differences in HGB or RBC recovery were observed between study groups. Significant differences between study groups were identified in osmotic fragility and osmotic gradient ektacytometry parameters. Of the 6 S-trait RCCs, 3/6 units were within the HCT, HGB and hemolysis thresholds set by the CS. The modified deglycerolization protocol provides a path for the routine cryopreservation of S-trait RBCs.

Guideline No. 448: Prevention of Rh D Alloimmunization

OBJECTIVE

This guideline provides recommendations for the prevention of Rh D alloimmunization (isoimmunization) in pregnancy, including parental testing, routine postpartum and antepartum prophylaxis, and other clinical indications for prophylaxis. Prevention of red cell alloimmunization in pregnancy with atypical antigens (other than the D antigen), for which immunoprophylaxis is not currently available, is not addressed in this guideline.

TARGET POPULATION

All Rh D-negative pregnant individuals at risk for Rh D alloimmunization due to potential exposure to a paternally derived fetal Rh D antigen.

OUTCOMES

Routine postpartum and antepartum Rh D immunoprophylaxis reduces the risk of Rh D alloimmunization at 6 months postpartum and in a subsequent pregnancy.

BENEFITS, HARMS, AND COSTS

This guideline details the population of pregnant individuals who may benefit from Rho(D) immune globulin (RhIG) immunoprophylaxis. Thus, those for whom the intervention is not required may avoid adverse effects, while those who are at risk of alloimmunization may mitigate this risk for themselves and/or their fetus.

EVIDENCE

For recommendations regarding use of RhIG, Medline and Medline in Process via Ovid and Embase Classic + Embase via Ovid were searched using both the trials and observational studies search strategies with study design filters. For trials, the Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects via Ovid were also searched. All databases were searched from January 2000 to November 26, 2019. Studies published before 2000 were captured from the grey literature of national obstetrics and gynaecology specialty societies, luminary specialty journals, and bibliographic searching. A formal process for the systematic review was undertaken for this update, as described in the systematic review manuscript published separately.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the SOGC's modified GRADE approach. See Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

The intended users of this guideline include prenatal care providers such as obstetricians, midwives, family physicians, emergency room physicians, and residents, as well as registered nurses and nurse practitioners.

TWEETABLE ABSTRACT

An updated Canadian guideline for prevention of Rh D alloimmunization addresses D variants, cffDNA for fetal Rh type, and updates recommendations on timing of RhIG administration.

SUMMARY STATEMENTS

RECOMMENDATIONS.

The effect of psychiatric decision unit services on inpatient admissions and mental health presentations in emergency departments: an interrupted time series analysis from two cities and one rural area in England

AIMS

High-quality evidence is lacking for the impact on healthcare utilisation of short-stay alternatives to psychiatric inpatient services for people experiencing acute and/or complex mental health crises (known in England as psychiatric decision units [PDUs]). We assessed the extent to which changes in psychiatric hospital and emergency department (ED) activity were explained by implementation of PDUs in England using a quasi-experimental approach.

METHODS

We conducted an interrupted time series (ITS) analysis of weekly aggregated data pre- and post-PDU implementation in one rural and two urban sites using segmented regression, adjusting for temporal and seasonal trends. Primary outcomes were changes in the number of voluntary inpatient admissions to (acute) adult psychiatric wards and number of ED adult mental health-related attendances in the 24 months post-PDU implementation compared to that in the 24 months pre-PDU implementation.

RESULTS

The two PDUs (one urban and one rural) with longer (average) stays and high staff-to-patient ratios observed post-PDU decreases in the pattern of weekly voluntary psychiatric admissions relative to pre-PDU trend (Rural: -0.45%/week, 95% confidence interval [CI] = -0.78%, -0.12%; Urban: -0.49%/week, 95% CI = -0.73%, -0.25%); PDU implementation in each was associated with an estimated 35-38% reduction in total voluntary admissions in the post-PDU period. The (urban) PDU with the highest throughput, lowest staff-to-patient ratio and shortest average stay observed a 20% (-20.4%, CI = -29.7%, -10.0%) level reduction in mental health-related ED attendances post-PDU, although there was little impact on long-term trend. Pooled analyses across sites indicated a significant reduction in the number of voluntary admissions following PDU implementation (-16.6%, 95% CI = -23.9%, -8.5%) but no significant (long-term) trend change (-0.20%/week, 95% CI = -0.74%, 0.34%) and no short- (-2.8%, 95% CI = -19.3%, 17.0%) or long-term (0.08%/week, 95% CI = -0.13, 0.28%) effects on mental health-related ED attendances. Findings were largely unchanged in secondary (ITS) analyses that considered the introduction of other service initiatives in the study period.

CONCLUSIONS

The introduction of PDUs was associated with an immediate reduction of voluntary psychiatric inpatient admissions. The extent to which PDUs change long-term trends of voluntary psychiatric admissions or impact on psychiatric presentations at ED may be linked to their configuration. PDUs with a large capacity, short length of stay and low staff-to-patient ratio can positively impact ED mental health presentations, while PDUs with longer length of stay and higher staff-to-patient ratios have potential to reduce voluntary psychiatric admissions over an extended period. Taken as a whole, our analyses suggest that when establishing a PDU, consideration of the primary crisis-care need that underlies the creation of the unit is key.

The selection and preparation of red cell components for intrauterine transfusion: A national survey

BACKGROUND AND OBJECTIVES

The practice regarding the selection and preparation of red blood cells (RBCs) for intrauterine transfusion (IUT) is variable reflecting historical practice and expert opinion rather than evidence-based recommendations. The aim of this survey was to assess Canadian hospital blood bank practice with respect to red cell IUT.

MATERIALS AND METHODS

A survey was sent to nine hospital laboratories known to perform red cell IUT. Questions regarding component selection, processing, foetal pre-transfusion testing, transfusion administration, documentation and traceability were assessed.

RESULTS

The median annual number of IUTs performed in Canada was 109 (interquartile range, 103-118). RBC selection criteria included allogeneic, Cytomegalovirus seronegative, irradiated, fresh units with most sites preferentially providing HbS negative, group O, RhD negative, Kell negative and units lacking the corresponding maternal antibody without extended matching to the maternal phenotype. Red cell processing varied with respect to target haematocrit, use of saline reconstitution (n = 4), use of an automated procedure for red cell concentration (n = 1) and incorporation of a wash step (n = 2). Foetal pre-transfusion testing uniformly included haemoglobin measurement, but additional serologic testing varied. A variety of strategies were used to link the IUT event to the neonate post-delivery, including the creation of a unique foetal blood bank identifier at three sites.

CONCLUSION

This survey reviews current practice and highlights the need for standardized national guidelines regarding the selection and preparation of RBCs for IUT. This study has prompted a re-examination of priorities for RBC selection for IUT and highlighted strategies for transfusion traceability in this unique setting.

Reconsidering Routine Repeat Group and Screens During Pregnancy-Personalizing Pregnancy Care

The group and screen (G&S) are performed in early pregnancy to identify clinically significant antibodies (CSA) that may necessitate fetal monitoring for hemolysis/anemia or affect RhIg eligibility. Guidelines vary, including differences between RhD-positive and negative patients, but typically, the G&S is repeated at 28 weeks, and sometimes pre-delivery. We reviewed data showing a low risk (0.01%-0.43%) of detecting a new CSA in late gestation (late alloimmunization) and the risk of late alloimmunization causing severe hemolysis/anemia is even lower at <0.01%. Routinely repeating a G&S at 28 weeks and delivery may not be necessary for healthy, low-risk pregnancies.

Comparison of automated solid phase versus manual saline indirect antiglobulin test methodology for non-ABO antibody titration: Implications for perinatal antibody monitoring

BACKGROUND

Accurate antibody titration is crucial in prenatal evaluations to identify patients who need clinical monitoring for hemolytic disease of the fetus and newborn (HDFN) causing fetal anemia. This study compares the established gold standard method of manual tube saline indirect antiglobulin testing (SIAT) with the newer automated solid phase (ASP) method of antibody titration and aims to establish the critical titer threshold for ASP that corresponds to the previously established SIAT critical threshold of ≥16 used in our laboratory.

STUDY DESIGN AND METHODS

One hundred fifty-seven prenatal and donor plasma samples with known antibodies were tested using both SIAT and ASP methodologies and results were compared.

RESULTS

The study found that ASP titers were, on average, 1.33 dilutions higher than SIAT titers. The critical titer cutoff for ASP was determined to be ≥32, which is one tube higher than the SIAT cutoff of ≥16.

DISCUSSION

The ASP method for antibody titration offers greater reproducibility and efficiency compared with manual SIAT titration. This study suggests that a titer cutoff of ≥32 is appropriate for most clinically significant antibodies using ASP. However, further research is needed to determine the comparability of ASP with SIAT in samples with multiple antibodies, anti-M antibodies, and other less common antibodies. Validation of the ASP titer cutoff against HDFN clinical outcomes is required before implementing this test for routine use in perinatal antibody titration.

How do I provide rare red cells to patients?

BACKGROUND

The demand for rare blood is expected to increase in Canada as its population continues to expand through immigration from diverse regions of the world.

MATERIAL AND METHODS

This paper outlines a national approach to providing rare red cells for patients through the Rare Blood Program of Canadian Blood Services (CBS). Data detailing the rare red cell requests and inventory managed by CBS' Rare Blood Program is provided.

RESULTS

The provision of rare red cells involves multiple considerations such as multidisciplinary communication, serologic/molecular confirmation, donor recruitment, inventory optimization and logistical factors.

CONCLUSION

The description of CBS' Rare Blood Program will inform others that seek to create, optimize, or expand programs that facilitate the provision of rare blood. New technologies such as next-generation sequencing may also affect how rare donors are identified and recruited in the future.

Use of selective phenotyping and genotyping to identify rare blood donors in Canada

BACKGROUND AND OBJECTIVES

The distribution of rare and specific red cell phenotypes varies between races and ethnicities. Therefore, the most compatible red cell units for patients with haemoglobinopathies and other rare blood requirements are most likely to be found in donors from similar genetic backgrounds. Our blood service introduced a voluntary question asking donors to provide their racial background/ethnicity. Results triggered additional phenotyping and/or genotyping.

MATERIALS AND METHODS

We analysed the results of additional testing performed between January 2021 and June 2022, and rare donors were added to the Rare Blood Donor database. We determined the incidence of various rare phenotypes and blood group alleles based on donor race/ethnicity.

RESULTS

Over 95% of donors answered the voluntary question; 715 samples were tested, and 25 donors were added to the Rare Blood Donor database, including five k-, four U-, two Jk(a-b-) and two D- - phenotypes.

CONCLUSION

Asking donors about their race/ethnicity was well received by donors, and the resulting selective testing enabled us to identify individuals with a higher likelihood of being rare blood donors, support patients with rare blood requirements and better understand the incidence of common and rare alleles and red blood cell phenotypes in the Canadian donor population.

Validation of a flow-cytometry-based red blood cell antigen phenotyping method

BACKGROUND AND OBJECTIVES

Current manual and automated phenotyping methods are based on visual detection of the antigen-antibody interaction. This approach has several limitations including the use of large volumes of patient and reagent red blood cells (RBCs) and antisera to produce a visually detectable reaction. We sought to determine whether the flow cytometry could be developed and validated to perform RBC phenotyping to enable a high-throughput method of phenotyping using comparatively miniscule reagent volumes via fluorescence-based detection of antibody binding.

MATERIALS AND METHODS

RBC phenotyping by flow cytometry was performed using monoclonal direct typing antisera (human IgM): anti-C, -E, -c, -e, -K, -Jk^a , -Jk^b and indirect typing antisera (human IgG): anti-k, -Fy^a , -Fy^b , -S, -s that are commercially available and currently utilized in our blood transfusion services (BTS) for agglutination-based phenotyping assays.

RESULTS

Seventy samples were tested using both flow-cytometry-based-phenotyping and a manual tube standard agglutination assay. For all the antigens tested, 100% concordance was achieved. The flow-cytometry-based method used minimal reagent volume (0.5-1 μl per antigen) compared with the volumes required for manual tube standard agglutination (50 μl per antigen) CONCLUSION: This study demonstrates the successful validation of flow-cytometry-based RBC phenotyping. Flow cytometry offers many benefits compared to common conventional RBC phenotyping methods including high degrees of automation, quantitative assessment with automated interpretation of results and extremely low volumes of reagents. This method could be used for high-throughput, low-cost phenotyping for both blood suppliers and hospital BTS.

Serologic reactivity of unidentified specificity in antenatal testing and hemolytic disease of the fetus and newborn: The BEST collaborative study

BACKGROUND

The clinical significance of serologic reactivity of unidentified specificity (SRUS) in pregnancy is not clear based on available literature. The aim of this study is to determine if SRUS is associated with hemolytic disease of the fetus and newborn (HDFN).

STUDY DESIGN AND METHODS

Retrospective data were collected from eight institutions over an 11-year study period (2010-2020), when available (5/8 sites). The outcome of the pregnancies with SRUS-no, mild, moderate, or severe HDFN-was determined.

RESULTS

SRUS was demonstrated in 589 pregnancies. After excluding those with incomplete data, a total of 284 pregnancies were included in the primary HDFN outcome analysis. SRUS was detected in 124 (44%) pregnancies in isolation, and none were affected by HDFN. Of 41 pregnancies with SRUS and ABO incompatibility, 37 (90%) were unaffected, and 4 (10%) were associated with mild HDFN. Of 98 pregnancies with SRUS and concurrent identifiable antibody reactivity(s), 80 (81%) were unaffected, and 19 (19%) were associated with mild to severe HDFN. There was 1 case of mild HDFN and 1 case of severe HDFN in the 21 pregnancies with SRUS, ABO incompatibility, and concurrent identifiable antibody reactivity(s), and 19 (90%) were unaffected by HDFN. Among all patients with repeat testing, newly identified alloantibodies or other antibodies were identified in 63 of 212 (30%) patients. Although most were not clinically significant, on occasion SRUS preceded clinically significant antibody(s) associated with HDFN (3%, 5/188).

CONCLUSION

The antenatal serologic finding of SRUS in isolation is not associated with HDFN but may precede clinically significant antibodies.

Severe fetal anemia caused by anti-Jra : Burst forming unit-erythroid colony formation inhibition assay suggesting possible erythroid suppression mechanism

BACKGROUND

The Jr blood group system includes a single, high-prevalence antigen, Jr^a , encoded by the ABCG2 gene. The impact of anti-Jr^a in pregnancy is variable, ranging from no clinical effect to severe anemia including some fetal deaths. Case reports have postulated that anti-Jr^a mediated fetal anemia is poorly hemolytic, suggesting other mechanisms of anemia may be involved.

STUDY DESIGN AND METHODS

We describe the case of severe anti-Jr^a mediated fetal anemia. At Canadian Blood Services laboratories, maternal anti-Jr^a was tested for phagocytic activity via a monocyte monolayer assay (MMA) and erythroid suppression via inhibition of burst forming unit-erythroid (BFU-E) colony formation assays. The New York Blood Center sequenced exons 4 and 7 of the ABCG2 gene.

RESULTS AND DISCUSSION

Sequencing of exons 4 and 7 of the ABCG2 gene revealed maternal compound heterozygosity for two nonsense mutations at exon 7 (c.706 C > T and c.784G > T). Fetal sequencing revealed the c.706C > T polymorphism. The MMA showed a borderline phagocytic index (around the cutoff of five for both donor segments tested [5 ± 1 and 7 ± 3]). The BFU-E colony formation inhibition assay suggested a dose-dependent inhibition of BFU-E colony formation with inhibition percentages of 4%, 11%, and 43% at maternal serum concentrations of 2%, 5%, and 10%, respectively. Our findings support the hypothesis that anti-Jr^a may impair erythropoiesis leading to clinically significant fetal/neonatal anemia. A referral to maternal fetal medicine is recommended if anti-Jr^a is detected in pregnancy, regardless of the titer.

KEL1 negative red cell transfusions for females of current or future child-bearing potential: A clinical impact and feasibility study

BACKGROUND

Anti-K is an alloantibody stimulated in response to the KEL1 antigen and may cause hemolytic disease of the fetus and newborn (HDFN). Provision of KEL1 negative blood to females of child-bearing potential was not our practice. We assessed the impact of our policy and assessed feasibility of a KEL1 negative transfusion policy.

STUDY DESIGN AND METHODS

This is a cohort study spanning Jan 1, 2007-Jun 30, 2017 in Hamilton, Canada. Data were obtained via our institution's transfusion database. Chart reviews of females age ≤45 with anti-K were performed; data on RBC KEL1 phenotype were obtained from the blood supplier when needed to ascertain the cause of alloimmunization. Descriptive analysis of hospital KEL1 negative inventory demand and supply was performed.

RESULTS

From Jan 2007-Jun 2017, 8.6% of all RBC units transfused were provided to females age ≤45. There were 111 females with detectable anti-K. Median age at time of antibody detection was 34 years (interquartile range 27-40) and 28 of 111 (25.2%) patients may have been alloimmunized by transfusion. Of 49 pregnancies, seven had complications due to anti-K. We estimated that our existing RBC inventory (with 16% units known to be KEL1 negative in 2017) is sufficient to meet demand and support a KEL1 negative transfusion policy for females age ≤45.

CONCLUSION

Transfusion was responsible for alloimmunization in 25% of females with anti-K over 10 years. Analysis of supply and demand can be used to inform feasibility of a KEL1 negative transfusion policy.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Immunohematology testing using umbilical cord blood: review of the literature, survey of practice and guidance development

BACKGROUND

Following delivery, blood tests are performed on umbilical cord blood (CB) to avoid neonatal venipuncture. Despite widespread and longstanding CB testing, no guidelines exist to suggest which immunohematology tests should be performed on CB.

STUDY DESIGN AND METHODS

We performed a scoping review, surveyed national practice, and developed guidance statements concerning CB testing. Database searches identified relevant articles. A survey was sent to all Canadian hospitals and transfusion laboratories that perform perinatal testing. A national panel of experts was convened to develop guidance statements.

RESULTS

A total of 116 articles met the inclusion criteria and were summarized. Literature on CB testing is limited; few studies have investigated laboratory testing methodologies or validated CB test results with peripheral samples. The survey was completed by 580/597 institutions (97%); 85% were community hospitals and 16% had a neonatal intensive care unit. There is diversity in the types of CB tests performed and variability in practice. While most centers order appropriately, some laboratories routinely perform CB tests that are not clinically indicated (e.g., direct antiglobulin testing for all neonates) and other do not perform CB tests when results would be beneficial (e.g., phenotype on CB when mother has a clinically significant antibody). Fifteen guidance statements were developed.

DISCUSSION

This study highlights variability in CB testing, likely reflecting evidence gaps, methodology differences between studies, and lack of guidelines. CB tests should only be performed when indicated and validated on this sample type. The presented guidance statements aim to standardize practice and encourage judicious CB sampling.

Cost-effectiveness of noninvasive fetal RhD blood group genotyping in nonalloimmunized and alloimmunized pregnancies

BACKGROUND

We sought to determine the cost-effectiveness of noninvasive fetal RhD blood group genotyping in nonalloimmunized and alloimmunized pregnancies in Canada.

STUDY DESIGN AND METHODS

We developed two probabilistic state-transition (Markov) microsimulation models to compare fetal genotyping followed by targeted management versus usual care (i.e., universal Rh immunoglobulin [RhIG] prophylaxis in nonalloimmunized RhD-negative pregnancies, or universal intensive monitoring in alloimmunized pregnancies). The reference case considered a healthcare payer perspective and a 10-year time horizon. Sensitivity analysis examined assumptions related to test cost, paternal screening, subsequent pregnancies, other alloantibodies (e.g., K, Rh c/C/E), societal perspective, and lifetime horizon.

RESULTS

Fetal genotyping in nonalloimmunized pregnancies (at per-sample test cost of C$247/US$311) was associated with a slightly higher probability of maternal alloimmunization (22 vs. 21 per 10,000) and a reduced number of RhIG injections (1.427 vs. 1.795) than usual care. It was more expensive (C$154/US$194, 95% Credible Interval [CrI]: C$139/US$175-C$169/US$213) and had little impact on QALYs (0.0007, 95%CrI: -0.01-0.01). These results were sensitive to the test cost (threshold achieved at C$88/US$111), and inclusion of paternal screening. Fetal genotyping in alloimmunized pregnancies (at test cost of C$328/US$413) was less expensive (-C$6280/US$7903, 95% CrI: -C$6325/US$7959 to -C$6229/US$7838) and more effective (0.19 QALYs, 95% CrI 0.17-0.20) than usual care. These cost savings remained robust in sensitivity analyses.

DISCUSSION

Noninvasive fetal RhD genotyping saves resources and represents good value for the management of alloimmunized pregnancies. If the cost of genotyping is substantially decreased, the targeted intervention can become a viable option for nonalloimmunized pregnancies.

Effect of cryopreservation on a rare McLeod donor red blood cell concentrate

Units of red blood cell (RBC) concentrates with rare phenotypes are typically not included in method validation studies for cryopreservation processes; rather, they are reserved for patients with rare blood needs. Some rare RBC phenotypes may demonstrate membrane abnormalities, like acanthocytosis as observed for RBCs with the McLeod phenotype, and are specifically banked for these rare attributes; however, the impact that rare RBC phenotypes have on post-thaw quality has not been well studied. To evaluate how a rare RBC phenotype is affected by the cryopreservation process, 4 RBC units, cryopreserved in 1993 using manual methods, were selected for evaluation. These RBCs included one with the McLeod phenotype and three with phenotypes not known to cause significant membrane changes. Post-thaw, an altered deglycerolization protocol, implemented to reduce supernatant glycerol after cryopreservation, was used before processing RBCs on an automated closed system (ACP 215; Haemonetics, Boston, MA) to accommodate the use of a closed system cell processor not available when the RBC units were previously cryopreserved. RBC quality was tested at 24 hours, 7 days, and 14 days post-deglycerolization. Before deglycerolization, an extracted sample from the thawed glycerolized RBC unit was used to obtain genetic material for phenotype confirmation. Genotyping confirmed the McLeod phenotype. When comparing McLeod with non-McLeod units, RBCs from the McLeod donor exhibited acanthocytosis, higher rigidity, and lower morphology scores than RBCs from the non-McLeod units post-deglycerolization. Hemolysis, however, was comparable across all 4 units, meeting regulatory standards. Therefore, McLeod RBCs can withstand cryopreservation, suggesting that units from these donors, glycerolized using older methods, can be deglycerolized using the ACP 215 and stored hypothermically for 14 days. It was also determined that genotyping can be performed on non-leukocyte-reduced cryopreserved RBCs, allowing for confirmation of genetic profiles of donor units banked before the implementation of molecular methods.

Units of red blood cell (RBC) concentrates with rare phenotypes are typically not included in method validation studies for cryopreservation processes; rather, they are reserved for patients with rare blood needs. Some rare RBC phenotypes may demonstrate membrane abnormalities, like acanthocytosis as observed for RBCs with the McLeod phenotype, and are specifically banked for these rare attributes; however, the impact that rare RBC phenotypes have on post-thaw quality has not been well studied. To evaluate how a rare RBC phenotype is affected by the cryopreservation process, 4 RBC units, cryopreserved in 1993 using manual methods, were selected for evaluation. These RBCs included one with the McLeod phenotype and three with phenotypes not known to cause significant membrane changes. Post-thaw, an altered deglycerolization protocol, implemented to reduce supernatant glycerol after cryopreservation, was used before processing RBCs on an automated closed system (ACP 215; Haemonetics, Boston, MA) to accommodate the use of a closed system cell processor not available when the RBC units were previously cryopreserved. RBC quality was tested at 24 hours, 7 days, and 14 days post-deglycerolization. Before deglycerolization, an extracted sample from the thawed glycerolized RBC unit was used to obtain genetic material for phenotype confirmation. Genotyping confirmed the McLeod phenotype. When comparing McLeod with non-McLeod units, RBCs from the McLeod donor exhibited acanthocytosis, higher rigidity, and lower morphology scores than RBCs from the non-McLeod units post-deglycerolization. Hemolysis, however, was comparable across all 4 units, meeting regulatory standards. Therefore, McLeod RBCs can withstand cryopreservation, suggesting that units from these donors, glycerolized using older methods, can be deglycerolized using the ACP 215 and stored hypothermically for 14 days. It was also determined that genotyping can be performed on non-leukocyte–reduced cryopreserved RBCs, allowing for confirmation of genetic profiles of donor units banked before the implementation of molecular methods.

Hypothermic storage of leukoreduced red blood cells for greater than 21 days is a safe alternative to irradiation

BACKGROUND

Irradiation of red blood cells (RBCs) inactivates residual donor T lymphocytes to prevent transfusion-associated graft-vs-host disease (TA-GVHD) but can have adverse effects on recipients and inventory management. Reported incidence of TA-GVHD is lower when leukoreduced RBCs and older blood products are transfused; therefore, the impact of leukoreduction and storage was evaluated as an alternative prevention strategy.

STUDY DESIGN AND METHODS

Effectiveness of leukoreduction filters on white blood cell (WBC) proliferation was evaluated by filtering buffy coat (BC) products and isolating residual WBCs. Additionally, leukoreduced RBCs were spiked with 5 × 10⁶ WBCs on Day 21 of hypothermic storage, then stored and processed on Days 7, 14, and 21 to obtain residual WBCs to investigate the impact of hypothermic storage on their viability and proliferative ability. Viability of residual WBCs was assessed by staining with annexin V and an antibody cocktail for flow cytometry analysis. Proliferative ability was assessed by placing carboxyfluorescein diacetate succinimidyl ester-labeled residual WBCs into culture for 6 days with phytohemagglutinin before flow cytometry assessment.

RESULTS

Filtration of BC units depleted WBCs, particularly T lymphocytes, to 0.001% ± 0.003% cells/unit, although proliferative activity remained consistent with prefiltration levels of WBCs. WBCs in stored RBCs remained viable even on Day 21 of storage; however, the proliferative activity decreased to 0.24% ± 0.41%.

CONCLUSIONS

Hypothermic storage of RBCs for 21 days or more is sufficient to inactivate T lymphocytes, which may help prevent TA-GVHD when irradiated RBCs are not available.

Approach to red blood cell antibody testing during pregnancy: Answers to commonly asked questions

OBJECTIVE

To provide family physicians with an understanding of blood bank tests performed during pregnancy. The value of routine blood type and antibody tests, as well as the follow-up required when a patient develops a red blood cell antibody or experiences a fetal-maternal hemorrhage (FMH) will be reviewed.

SOURCES OF INFORMATION

The approach described is based on the authors' clinical expertise and peer-reviewed literature from 1967 to 2020.

MAIN MESSAGE

An ABO and RhD group and antibody screen test is performed on every pregnant patient during the first trimester. Although antibodies to red blood cell antigens occur infrequently, some can lead to substantial adverse fetal or neonatal consequences including hemolytic disease of the fetus and newborn. Early identification and quantification of important antibodies ensures that at-risk mothers are referred to and followed by obstetricians experienced with high-risk care. Another valuable and related test is the FMH test. For RhD-negative women, these tests are performed at every delivery and following antepartum events that could contribute to FMH. This test determines the number of fetal red blood cells in the maternal circulation and is used to determine the dose of Rh immune globulin an RhD-negative mother requires to prevent alloimmunization to fetal RhD.

CONCLUSION

An understanding of blood bank tests performed during pregnancy and their role and limitations is vital to optimal practice and aids clinicians in their decision making. When there is doubt or confusion regarding antenatal testing or immunoprophylaxis, consult the regional laboratory or transfusion medicine specialists for additional guidance.

Report on the 19th International Society of Blood Transfusion Platelet Immunology Workshop 2018

BACKGROUND AND OBJECTIVES

The aims of the 19th International Society of Blood Transfusion Platelet Immunology Workshop were to compare the sensitivity and specificity of in-house and commercially available methods for the detection of alloantibodies against human platelet antigens. Survey regarding laboratory management of samples collected for the diagnosis of foetal neonatal alloimmune thrombocytopenia was also conducted.

MATERIALS AND METHODS

Twenty-nine laboratories from 17 countries were invited to participate. Seven serum or plasma samples for antibody identification and eight DNA samples for genotyping were sent to participating laboratories. Additionally, samples, critical reagents, materials and instructions for three exercises, one using a commercial kit (Pak Lx), one on platelet preparation for the detection of anti-HPA-3 antibodies and one for testing four anti-CD109 monoclonal antibodies for anti-HPA-15 antibody detection, were provided.

RESULTS

Anti-HPA-1a, anti-HPA-2b, anti-HPA-5b and anti-GPIV were detected by the majority of the 28 reporting laboratories using their respective in-house MAIPA assay and/or a commercially available assay. Conversely, very few laboratories correctly identified anti-HPA-3a and HPA-15b. DNA genotyping of HPA and HLA alleles was highly accurate, with just a few discrepancies relative to the expected results. The Pak Lx kit has proven reliable for detecting anti-HPA-1a, anti-HPA-5a and anti-HLA; however, it failed at identifying an anti-HPA-3a in a clinical sample.

CONCLUSIONS

Some anti-platelet alloantibodies are reliably and consistently detected, yet others remain difficult to detect. Genotyping of HPA and HLA alleles has proven to be highly accurate and robust. Future work should focus on optimizing the detection of anti-HPA-3 and anti-HPA-15 antibodies.

What is the impact of psychiatric decision units on mental health crisis care pathways? Protocol for an interrupted time series analysis with a synthetic control study

BACKGROUND

The UK mental health system is stretched to breaking point. Individuals presenting with mental health problems wait longer at the ED than those presenting with physical concerns and finding a bed when needed is difficult - 91% of psychiatric wards are operating at above the recommended occupancy rate. To address the pressure, a new type of facility - psychiatric decision units (also known as mental health decision units) - have been introduced in some areas. These are short-stay facilities, available upon referral, targeted to help individuals who may be able to avoid an inpatient admission or lengthy ED visit. To advance knowledge about the effectiveness of this service for this purpose, we will examine the effect of the service on the mental health crisis care pathway over a 4-year time period; the 2 years proceeding and following the introduction of the service. We use aggregate service level data of key indicators of the performance of this pathway.

METHODS

Data from four mental health Trusts in England will be analysed using an interrupted time series (ITS) design with the primary outcomes of the rate of (i) ED psychiatric presentations and (ii) voluntary admissions to mental health wards. This will be supplemented with a synthetic control study with the same primary outcomes, in which a comparable control group is generated for each outcome using a donor pool of suitable National Health Service Trusts in England. The methods are well suited to an evaluation of an intervention at a service delivery level targeting population-level health outcome and the randomisation or 'trialability' of the intervention is limited. The synthetic control study controls for national trends over time, increasing our confidence in the results. The study has been designed and will be carried out with the involvement of service users and carers.

DISCUSSION

This will be the first formal evaluation of psychiatric decision units in England. The analysis will provide estimates of the effect of the decision units on a number of important service use indicators, providing much-needed information for those designing service pathways.

TRIAL REGISTRATION

primary registry: isrctn.com Identifying number: ISRCTN77588384 Link: Date of registration in primary registry: 27/02/2020.

PRIMARY SPONSOR

St George's, University of London, Cramner Road, Tooting, SW17 ORE. Primary contact: Joe Montebello.

Monitoring of prenatal patients using a combined antibody titre for Rh and non-Rh antibodies

OBJECTIVES

This was a laboratory exercise designed to determine whether combined antibody titrations in the presence of multiple antibodies achieve a critical level earlier or at the same time as antibodies having individual antibody titrations.

BACKGROUND

Management of haemolytic disease of the fetus and newborn involves monitoring maternal antibody concentration by antibody titration. Separate titrations are generally performed for each antibody.

METHOD

Thirty-one samples containing combinations of two different Rh and/or non-Rh antibodies were examined with separate titres for each antibody and one single combined titration.

RESULTS

Of 31 samples, 19 (61.3%) showed an increased combined titre. Of 12 samples that showed no increase, 10 contained a separate titre of <1 for either one or both antibodies. Where both antibodies had a separate titre of ≥1, 15 of 17 (88.2%) showed an increased combined titre. In contrast to the separate titration method, no decrease in titre level was observed using the combined method.

CONCLUSION

Where two antibodies are present, titrations performed by a combined method will produce titre levels equal to or higher than antibodies titred individually. Therefore, a combined titration can be expected to reach a critical titre level as early as, or earlier in gestation than, antibodies monitored by a single titration method. Further studies relating fetal outcomes to titration methodology would be valuable in determining the validity of this approach for prenatal management. Cost-effectiveness of this approach to prenatal screening should also be assessed.

Using anti-Xa level for adjusting intravenous unfractionated heparin infusion in peripartum thromboembolic disease

BACKGROUND

Intravenous unfractionated heparin infusion is often used to minimize the duration of time without anticoagulation around delivery in pregnant patients with high thrombotic risk. Activated partial thromboplastin time is commonly used to monitor and adjust heparin dose. However, using activated partial thromboplastin time is problematic in pregnancy because activated partial thromboplastin time response to unfractionated heparin is attenuated due to elevated Factor VIII levels and may lead to incorrect dosing.

CASE

We report a case of deep venous thrombosis occurring in a term pregnancy managed by intravenous unfractionated heparin adjusted using anti-Xa level around the time of delivery. We modified the intravenous unfractionated heparin nomogram by using anti-Xa levels instead of activated partial thromboplastin time and observed lower dosing of unfractionated heparin than otherwise required to achieve and maintain target levels.

CONCLUSION

This report demonstrates the feasibility and effectiveness of using anti-Xa level to monitor and adjust intravenous unfractionated heparin infusion in pregnancy.

Cost-effectiveness of yoga for managing musculoskeletal conditions in the workplace

Background

Back pain and musculoskeletal conditions negatively affect the health-related quality of life (HRQL) of employees and generate substantial costs to employers.

Aims

To assess the cost-effectiveness of yoga for managing musculoskeletal conditions.

Methods

A randomized controlled trial evaluated an 8-week yoga programme, with a 6-month follow-up, for National Health Service (NHS) employees. Effectiveness in managing musculoskeletal conditions was assessed using repeated-measures generalized linear modelling for the Roland-Morris Disability Questionnaire (RDQ) and the Keele STarT Back Screening Tool. Cost-effectiveness was determined using area-under-the-curve linear regression for assessing HRQL from healthcare and societal perspectives. The incremental cost per quality-adjusted life year (QALY) was also calculated. Sickness absence was measured using electronic staff records at 6 months.

Results

There were 151 participants. At 6 months, mean differences between groups favouring yoga were observed for RDQ [-0.63 (95% CI, -1.78, 0.48)], Keele STarT [-0.28 (95% CI, -0.97, 0.07)] and HRQL (0.016 QALY gain). From a healthcare perspective, yoga yielded an incremental cost-effectiveness ratio of £2103 per QALY. Given a willingness to pay for an additional QALY of £20 000, the probability of yoga being cost-effective was 95%. From a societal perspective, yoga was the dominant treatment compared with usual care. At 6 months, electronic staff records showed that yoga participants missed a total of 2 working days due to musculoskeletal conditions compared with 43 days for usual care participants.

Conclusions

Yoga for NHS employees may enhance HRQL, reduce disability associated with back pain, lower sickness absence due to musculoskeletal conditions and is likely to be cost-effective.

Survey of Reproductive Experiences and Outcomes of Cancer Survivors Who Stored Reproductive Material Before Treatment

STUDY QUESTION

What are the reproductive experiences and outcomes of people who store reproductive material before cancer treatment?

SUMMARY ANSWER

Of respondents who had tried to achieve pregnancy since completing cancer treatment almost all had succeeded, in most cases through natural conception.

WHAT IS KNOWN ALREADY

People of reproductive age who are diagnosed with cancer can cryopreserve reproductive material to guard against the adverse effects on fertility of gonadotoxic treatment. Little is known about the reproductive outcomes of people who undergo fertility preservation before cancer treatment.

STUDY DESIGN, SIZE, DURATION

Cross-sectional survey.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women and men who had stored reproductive material before cancer treatment at two private and one public fertility clinics up to June 2014 and were at least 18 years old at the time were identified from medical records and invited to complete an anonymous questionnaire about their reproductive experiences.

MAIN RESULTS AND THE ROLE OF CHANCE

Of the 870 potential respondents 302 (171 female and 131 male) returned completed questionnaires yielding a response rate of 34.5% (39.5% and 29.7% for female and male respondents, respectively). Current age was similar for women and men (37.2 years) but men had been diagnosed with cancer significantly earlier in life than women (28.2 versus 30.3 years, P = 0.03). Almost two-thirds of respondents wished to have a child or another child in the future, some of whom knew that they were unable to. One in ten respondents was a parent before the cancer diagnosis and around one-third had had a child since diagnosis or was pregnant (or a partner in pregnancy) at the time of the survey. Of those who had tried to conceive since completing cancer treatment (N = 119) 84% (79% of women and 90% of men) had had a child or were pregnant (or a partner in pregnancy). Most of the pregnancies since the diagnosis of cancer occurred after natural conception (58/100, 58%). Of the 22 women (13% of all women) and 35 men (27% of all men) who had used their stored reproductive material four women (18%) and 28 men (80%) had had a child or were pregnant or a partner in pregnancy at the time of completing the survey. The most commonly stated reason for not using the stored material was not being ready to try for a baby.

LIMITATIONS, REASON FOR CAUTION

The relatively low response rate, particularly among men, means that participation bias may have influenced the findings. As type of cancer was self-reported and we did not ask questions about respondents' cancer treatments, it is not possible to link reproductive outcomes to type of cancer or cancer treatment. Also, there is no way of comparing the sample with the populations they were drawn from as data on reproductive outcomes of people who store reproductive material before cancer treatment are not collected routinely. This might have led to over- or underestimates of the reproductive experiences and outcomes reported in this paper.

WIDER IMPLICATIONS OF THE FINDINGS

The findings add to the limited evidence about the reproductive outcomes of this growing group of people and can be used to inform the advice given to those contemplating fertility preservation in the context of cancer.

STUDY FUNDING/COMPETING INTERESTS

The study was funded by the National Health and Medical Research Council (APP1042347). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

Severe hemolytic disease of the fetus and newborn due to allo-anti-D in a patient with a partial DEL phenotype arising from the variant allele described as RHD*148+1T (RHD*01EL.31)

BACKGROUND

RhD DEL variants may show complete or partial expression of RhD epitopes. There have been only rare reports of anti-D causing hemolytic disease of the fetus and newborn (HDFN) in this context. We report a case of severe HDFN associated with a recently described DEL variant.

CASE REPORT

A multiparous woman presented with an allo-anti-D and showed incongruent phenotyping and genotyping results on initial study. Further investigations identified the RHD mutation, defined as RHD*148+1T and named RHD*01EL.31, which had been previously associated with a DEL phenotype. Extended RhD phenotyping by adsorption-elution showed that there was reactivity with four of nine monoclonal anti-D antibodies, suggesting a partial DEL phenotype. The first child showed no clinical evidence of HDFN, although the cord direct antiglobulin test was positive. The second child developed fetal anemia treated with intrauterine transfusion, and neonatal hyperbilirubinemia requiring exchange transfusion.

CONCLUSION

The RHD allele, RHD*148+1T, results in a partial Del phenotype, and the anti-D formed in pregnant women with this phenotype is capable of causing severe HDFN.

Kynurenine pathway metabolism and the neurobiology of treatment-resistant depression: Comparison of multiple ketamine infusions and electroconvulsive therapy

Current first-line antidepressants can take weeks or months to decrease depressive symptoms. Low dose ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, shows potential for a more rapid antidepressant effect, with efficacy also evident in previously treatment-resistant populations. However, a greater understanding of the physiological mechanisms underlying such effects is required. We assessed the potential impact of ketamine infusion on neurobiological drivers of kynurenine pathway metabolism in major depression (HPA axis hyperactivity, inflammation) in patients with treatment-resistant depression compared to gender-matched healthy controls. Furthermore, we assessed these biomarkers before and after electroconvulsive therapy (ECT), which is currently the gold standard for management of treatment-resistant depression. As previously demonstrated, treatment with ketamine and ECT was associated with improved depressive symptoms in patients. At baseline, waking cortisol output was greater in the ECT cohort, kynurenine was greater in the ketamine cohort, and kynurenic acid was lower in patients compared to healthy controls, although inflammatory markers (IL-6, IL-8, IL-10 or IFN-γ) were similar in patients and controls. Furthermore, in patients who responded to ECT, the cortisol awakening response was decreased following treatment. Despite a trend towards reduced kynurenine concentrations in those who responded to ketamine, ketamine was not associated with significant alterations in any of the biomarkers assessed.

The microbiota-gut-brain axis as a key regulator of neural function and the stress response: Implications for human and animal health

The brain-gut-microbiota axis comprises an extensive communication network between the brain, the gut, and the microbiota residing there. Development of a diverse gut microbiota is vital for multiple features of behavior and physiology, as well as many fundamental aspects of brain structure and function. Appropriate early-life assembly of the gut microbiota is also believed to play a role in subsequent emotional and cognitive development. If the composition, diversity, or assembly of the gut microbiota is impaired, this impairment can have a negative impact on host health and lead to disorders such as obesity, diabetes, inflammatory diseases, and even potentially neuropsychiatric illnesses, including anxiety and depression. Therefore, much research effort in recent years has focused on understanding the potential of targeting the intestinal microbiota to prevent and treat such disorders. This review aims to explore the influence of the gut microbiota on host neural function and behavior, particularly those of relevance to stress-related disorders. The involvement of microbiota in diverse neural functions such as myelination, microglia function, neuronal morphology, and blood-brain barrier integrity across the life span, from early life to adolescence to old age, will also be discussed. Nurturing an optimal gut microbiome may also prove beneficial in animal science as a means to manage stressful situations and to increase productivity of farm animals. The implications of these observations are manifold, and researchers are hopeful that this promising body of preclinical work can be successfully translated to the clinic and beyond.