Routine testing of fetal Rhesus D status in Rhesus D negative women using cell-free fetal DNA: an investigation into the preferences and information needs of women.

OBJECTIVE: The goal of this study is to investigate women's preferences and information needs for routine implementation of fetal Rhesus D (RhD) typing using cell-free fetal DNA. METHODS: A questionnaire was developed following focus groups and interviews with both health professionals and RhD negative (RhD-) women offered fetal RhD genotyping within a research study and distributed to RhD- women attending routine antenatal appointments in four National Health Service hospitals. Current knowledge of blood types, anti-D administration, fetal RhD genotyping and future practices were explored. RESULTS: A total of 19 respondents participated in interviews and focus groups, and 270 respondents completed the questionnaires. Questionnaire respondents overwhelmingly felt that the test should be offered to all RhD- women (92.1%), and 75.9% said that they would accept this test. Most were happy to have the test even if it involved extra blood tests (89.3%) or appointments (79%). The knowledge of blood groups was poor. Although 90.7% knew that the baby could have a different blood group from themselves, only 34% knew that blood groups are inherited from both parents. More than 40% were not aware that anti-D would not be required if their baby was RhD-. CONCLUSIONS: Women would welcome the introduction of routine fetal RhD genotyping. Information leaflets and training of midwives will be essential for implementation to ensure good understanding regarding testing.

ABO reverse grouping: effect of varying concentrations of the enzyme bromelain.

Proteolytic enzymes can be extremely useful for the identification of clinically significant antibodies in blood grouping; however, they can also be destructive to certain agglutination reactions. ABO antibodies are the most clinically significant. A review of the literature reveals little research involving proteolytic enzymes and IgM antibodies. This study investigates the effects of various concentrations of the proteolytic enzyme bromelain on the agglutination of reagent A1 and B cells with donor plasma during ABO reverse grouping on the Olympus PK 7300 automated serology analyser. The optimum bromelain concentration improved or enhanced antigen-antibody reactions, causing a reduction in ABO failures. The results were analysed using an ANOVA test. An anomalous result was obtained at 0% bromelain where less ABO failures were generated than expected. Although most results were not statistically significant, the optimum bromelain concentration for ABO reverse grouping indicated was 0.25%. This work also highlighted the fact that ABO failures can be attributed to other factors such as sensitivity of reagent cells and antibody avidity. This study identified limitations and problems with the methods used and presents recommendations for future research which may assist in the clarification of the role of proteolytic enzymes in ABO reverse grouping.

[Labile blood products and their preparation]. / Produits sanguins labiles et leur préparation.

Licensed labile blood components are put down on a regulatory list by the French Health Authority. They are prepared by the French National Blood Service and controlled according to regulatory and validated procedures. Depending on the origin of the blood, labile blood components are either homologous (donors) or autologous (from patients). Blood components (red cell concentrates, platelet concentrates and fresh frozen plasma) are processed within sterile closed disposable systems using either post-donation processing of whole blood or apheresis technology. All homologous blood components are leuco-reduced. Depending on specific settings, blood components could be washed, gamma irradiated or cryopreserved. Fresh frozen plasma is either "donor retested" after quarantine or viro-attenuated by solvent detergent treatment. Release is only allowed after a full conformity control of each blood component unit.

Suspected neonatal isoerythrolysis in two Baird's tapirs (Tapirus bairdii).

Two Baird's tapir (Tapirus bairdii) calves born at the Columbus Zoo from the same sire and dam developed hemolytic anemia that was consistent in history and clinical signs with neonatal isoerythrolysis (NI). One calf developed severe, fatal hemolytic anemia after being fed maternal colostrum, and the other developed moderate hemolytic anemia after being fed equine colostrum. No cross-reactivity was demonstrated between sire and dam blood samples, and both tapirs possessed serum antibodies reactive against equine blood group Ca and antigens reactive with several equine blood group D antibodies. Electrophoresis demonstrated significant genetic diversity between tapir and equine blood proteins. Agglutination testing demonstrated strong reactivity between a far greater percentage of equine colostrum samples when tested against sire and dam tapir blood (61% and 65%, respectively) than would be expected for equine blood (2%). These data are suggestive of a diagnosis of NI but are not definitive. Further study is required to determine whether NI occurs in tapirs and whether equine colostrum is harmful to tapir calves.

[Type and Screen: immunohematological safety is ensured and costs are lowered]. / "Type and screen": die immunhämatologische Sicherheit ist gewährleistet und die Kosten werden gesenkt.

UNLABELLED: TYPE AND SCREEN: (T + S) means: no routine cross match before transfusion. ABO- and Rh-(Blgr) blood groups (type) are done and irregular allo-antibodies are sought (screen). If screen is negative, instant saline test (IST) or Blgr control, and if screen is positive, conventional cross match is done. GOALS: Are all clinically relevant antibodies discovered with T + S? Are laboratory costs lower? METHODS AND STUDY DESIGN: Prospective study over more than 3 years. Blgr and cross match were done in tubes and AB screen and antibody identification (panel) were sought using the gel-test (DiaMed) with bromelin (enz) and LISS antiglobulin test (IAT). Underlying all testing were the directives of the Swiss blood donation services. RESULTS: Enzyme-only positive antibodies are not relevant for blood transfusion, as shown by our data from more than 10000 comparisons of enz- and IAT-screens. 32 patients with positive enz-antibodies and negative cross match were transfused without problems. The enz-screen was abandoned for more than 12 months' follow-up in more than 20000 transfused patients. Before using the T + S, one unit of transfused RBC needed (on average) 3.7 cross matches, and after introduction of T + S only 0.3. Although the number of T + S increased significantly, we effectively saved some CHF 280000 per year.

Métodos para el pesquisaje de anticuerpos contra antigenos de grupos sanguineos del sistema ABO humano / Methods for the screeninig antibodies of the human ABO blood group system

Para el pesquisaje inicial de anticuerpos contra antígenos de grupos sanguíneos (tanto en los sueros de ratón como en los sobrenadantes de hibridomas) se utilizó la técnica de aglutinación en microplacas empléandose hematíes A1,A2,Ax, B y O tratados con bromelina. Una vez identificados los clones de hibridomas productores, se estudiaron sus correspondientes líquidos ascíticos por los métodos de aglutinación en microplacas, en tubos por centrifugación y sedimentación y en láminas, lo que permitió demostrar que con el método de pesquisaje inicial se puede procesar un elevado número de muestras y utilizar pequeñas cantidades de sobredonantes, además de que permite seleccionar reactivos adecuados para el fenotipo de grupos sanguíneos en tubos, en láminas y microplacas, que son las 3 técnicas más usadas en el mundo para el inmunofenotipaje de los donantes

Métodos para el pesquisaje de anticuerpos contra antigenos de grupos sanguineos del sistema ABO humano / Methods for the screeninig antibodies of the huan ABO blood group system

Para el pesquisaje inicial de anticuerpos contra antígenos de grupos sanguíneos (tanto en los sueros de ratón como en los sobrenadantes de hibridomas) se utilizó la técnica de aglutinación en microplacas empléandose hematíes A1,A2,Ax, B y O tratados con bromelina. Una vez identificados los clones de hibridomas productores, se estudiaron sus correspondientes líquidos ascíticos por los métodos de aglutinación en microplacas, en tubos por centrifugación y sedimentación y en láminas, lo que permitió demostrar que con el método de pesquisaje inicial se puede procesar un elevado número de muestras y utilizar pequeñas cantidades de sobredonantes, además de que permite seleccionar reactivos adecuados para el fenotipo de grupos sanguíneos en tubos, en láminas y microplacas, que son las 3 técnicas más usadas en el mundo para el inmunofenotipaje de los donantes (AU)

[Anti-Ge2 in a Ge: -2, -3 patient]. / Anti-Ge2 en un paciente Ge: -2, -3.

The first report of anti-Ge2 in our country, found in a Ge: -2, -3, A1B Rh+ patient is presented. The IgG + IgM antibody reacted in a low ionic strength medium, with a titre of 128. ABO compatible red blood cells labelled with 51Cr had a very shortened life span, with high haemolytic rate. The transfusion problems posed by this patient and the therapeutic autotransfusional approach carried out are commented.

Efficiency of blood use and prospects for autologous transfusion in general surgery.

A 6-month retrospective audit of crossmatch and transfusion practice in a general surgical unit has been performed. Inefficiencies in blood ordering practices have been demonstrated and the value of performing a local audit to allow estimation of blood needs has been proven. Using criteria based on the suggested tariff for operations derived from this audit, only a small number of general surgical patients would be considered as potential autologous blood donors.

Developing techniques in blood transfusion.

Expansion of transfusion medicine has led to an increasing awareness of the importance of its practice. Specialists in this branch of haematology whose main aim is to provide adequate and safe supplies of blood (and blood products) and to ensure these are used appropriately, are increasingly aware that to do this efficiently requires the development and utilization of new laboratory and technical procedures. Review of cross-matching techniques has led to the introduction of more rapid methods using low ionic strength saline. Use of monoclonal antibodies for blood grouping has made use of new technology, whilst allowing scarce human plasma to be used more appropriately for therapeutic purposes. Similarly, the implementation of a more rational approach to blood ordering, as in a maximum surgical blood-order schedule, allows for the more efficient use of donor blood. The use of microtitre plates for grouping and cross-matching techniques allows for speed and economy in the transfusion laboratory. Their use is also associated with increased automation and computer use. The possibility of using solid-phase techniques, monocyte-macrophage assays and antibody-dependent cellular cytotoxicity assays introduces new techniques differing markedly from time-honoured liquid-phase serology methods. The application of flow cytometry, which has already been shown to be useful in many aspects of haematology, is also of benefit in the field of blood transfusion science. Safety of blood transfusion is an important aspect of its practice and has led to the introduction and development of screening tests for donor blood to exclude infection risks from such organisms as HIV-1, hepatitis B and non-A, non-B hepatitis. Another approach to ensure the safety of transfused blood has been increased usage of autologous transfusion by means of both predeposit donation and intraoperative cell salvage.

Patients with anti-Vel--immunohematological characterization and transfusion management.

As reported by other authors we can confirm that the frequency of the blood group Vel negative in Lower Saxony is 1:4000. We report on a patient whose serological characteristics (IgM- and IgA-anti-Vel) made the transfusion of Vel positive blood impossible. Since it was not possible to obtain sufficient Vel negative red cell units in time, the patient was convinced to donate blood for autologous transfusions. This should be the procedure of first choice in the transfusion management of such patients.

Differences in substrate specificities for cysteine proteinases used in blood group serology, and the use of bromelain in a two-phase inhibitor technique.

Because substrate specificities differ between proteolytic enzymes and because knowledge of the optimal enzyme activity levels is necessary in order to standardize procedures used in antibody screening, a study was made of the best common assay method for the routinely employed enzymes bromelain, papain and ficin. Casein degradation was found better suited to this purpose than azoalbumin. With standardization achieved, a useful two-phase bromelain inhibitor technique was devised using bromelain at 20 casein units of activity. This method improved upon the one-stage bromelain technique in terms of sensitivity, freedom from false positive reactions and it compared well with the two-phase papain inhibitor technique.

The pH optima for papain and bromelain treatment of red cells.

The action of papain and bromelain, prepared over a pH range from 4.6 to 8.6, was evaluated for the ability to render red cells agglutinable by five incomplete antibodies of differing blood group specificities using a two-stage technique. The optimal pH for treatment of red cells by activated papain or bromelain was between 5.4 and 5.8. Above this pH range, a fall in serological sensitivity was apparent which was much more pronounced with papain than with bromelain. The optimal pH for enzyme treatment of red cells can be achieved in two-stage techniques, but not in one-stage techniques due to the buffering effect of serum proteins.

Tc-99m red blood cells for the study of rapid hemolytic processes associated with heterologous blood transfusions.

Chromium-51 labeled erythrocytes (Cr-51 RBC) are suitable for the study of hematologic disorders which involve relatively slow destruction of circulating erythrocytes, taking several days to several weeks. However, Cr-51 RBC are not suitable for investigating rapid hemolytic processes which occur within a matter of a few hours due to the variable and unpredictable elution of Cr-51 from the erythrocytes during the first 24 hours or so. Imaging, which could be useful in identifying organ systems involved in the hemolytic process, cannot be performed with Cr-51 RBC because of the high dose commitment caused by the low yield of gamma rays from Cr-51 (2). A method of labeling RBC with Tc-99m, which results in a radiopharmaceutical that combines the excellent dosimetric and imaging qualities of Tc-99m with an extremely stable bond between the Tc-99m and the RBC, is reported. The successful application of this technique in providing red cell support for a cancer patient with an unusual history of intravascular hemolytic transfusion reactions is also reported.