Evaluating automated titre score as an alternative to continuous flow analysis for the prediction of passive anti-D in pregnancy.

OBJECTIVES: To evaluate the potential of the automated titre score (TS) as an alternative method to continuous flow analysis (CFA) for the prediction of the nature of anti-D in pregnancy. BACKGROUND: The 2016 revised British Society for Haematology (BSH) antenatal guidelines recommended a measurement of anti-D concentration by CFA to ensure the detection of potential immune anti-D. Due to high referral costs and resource pressures, uptake has been challenging for hospital laboratories. Serious Hazards of transfusion (SHOT) data have previously shown that this has contributed to missed antenatal follow ups for women with immune anti-D and neonates affected by haemolytic disease of the fetus/newborn. METHODS/MATERIALS: In this multicentre comparative study, samples referred for CFA quantification were also tested by an ORTHO VISION automated anti-D indirect antiglobulin test (IAT) serial dilution and then converted to TS. CFA results and history of anti-D prophylaxis were used to categorise samples as passive or immune, with the aim of determining a potential TS cut-off for CFA referral of at risk patients. RESULTS: Five UK National Health Service (NHS) trusts generated a total of 196 anti-D TS results, of which 128 were classified as passive and 68 as immune. Diagnostic testing of CFA and TS values indicated a TS cut-off of 35 to assist in distinguishing the nature of anti-D. Using this cut-off, 175 (89%) results were correctly assigned into the passive or immune range, giving a specificity of 92.19% and a negative predictive value of 91.47%. CONCLUSION: TS in conjunction with clinical and anti-D prophylaxis history can be used as a viable and cost-effective alternative to CFA in a hospital laboratory setting.

Applicability of papain solutions in immunohematology.

OBJECTIVE: To compare the enzyme activity of different presentations of papain solution to validate in-house preparations. METHODS: Two papain solutions were prepared, and the third presentation was a commercial solution. Tests were carried out with samples of red cells typed as weak RhD. RESULTS: In-house prepared papain solutions showed similar enzyme reactivity, and statistically no differences compared to the enzyme activity of the commercial solution. CONCLUSION: Evaluating the cost-benefit ratio, the in-house prepared papain solutions present more economic advantages, and can be incorporated into immunohematological routines as a way to cope with periods of financial crisis and cost-containment policies.

Applicability of papain solutions in immunohematology / Aplicabilidade de soluções de papaína em imuno-hematologia

ABSTRACT Objective: To compare the enzyme activity of different presentations of papain solution to validate in-house preparations. Methods: Two papain solutions were prepared, and the third presentation was a commercial solution. Tests were carried out with samples of red cells typed as weak RhD. Results: In-house prepared papain solutions showed similar enzyme reactivity, and statistically no differences compared to the enzyme activity of the commercial solution. Conclusion: Evaluating the cost-benefit ratio, the in-house prepared papain solutions present more economic advantages, and can be incorporated into immunohematological routines as a way to cope with periods of financial crisis and cost-containment policies.

RESUMO Objetivo: Comparar a atividade enzimática de diferentes apresentações de solução de papaína para validação de preparados in-house. Métodos: Foram preparadas duas soluções de papaína, e a terceira apresentação tratou-se de uma solução comercial. Os testes comparativos das reações enzimáticas foram realizados com amostras de hemácias tipadas como RhD fraco. Resultados: As soluções de papaína preparadas in-house apresentaram reatividade enzimática semelhante e estatisticamente sem diferenças em comparação com a atividade enzimática da solução comercial. Conclusão: Avaliando-se a relação entre custo e benefício, as soluções de papaína preparadas in-house são economicamente vantajosas, podendo ser incorporadas às rotinas imuno-hematológicas como forma de enfrentamento em períodos de crise financeira e em políticas de retenção de gastos.

Impact of non-invasive fetal RhD genotyping on management costs of rhesus-D negative patients: results of a French pilot study.

OBJECTIVES: Fetal rhesus D (RhD) status determination using circulating cell-free fetal DNA from maternal plasma or serum is now recognized in Europe as a reliable and useful tool. A few countries are presently using this test in their management policy of rhesus D negative patients. The objective of this study is to evaluate the impact of this test on the costs of managing RhD-negative pregnant women, whether or not they are allo-immunized. STUDY DESIGN: A prospective follow-up of rhesus D negative women during their pregnancy was performed in three French obstetric departments. Non-invasive fetal RhD genotyping was performed in the first trimester and pregnancies were followed The costs of all procedures (biological tests and medication) associated with patient management in relation to their RhD-negative status were calculated according to different management options. RESULTS: A comprehensive follow-up, including medical and biological monitoring, was obtained for 99 of the 101 patients included in the study. Patients were separated into two groups: the "Adverse Event" group (AE, n=23) for which a potentially sensitizing event occurred and the "No Adverse Event" group (NAE, n=76). Fetal RhD status was accurately determined in all cases. The mean cost per patient was estimated at 237€ (range: 115-644) with differences observed depending on the group, notably 331€ (range: 236-644) for the AE group and 208€ (range: 115-366) for the NAE group. Various cost simulations were performed according to various policies of allo-immunization antenatal prophylaxis. Variations ranged from +36.2% to +105.3%. CONCLUSION: This study demonstrates that fetal RhD genotyping early during pregnancy is not an effective cost-reduction strategy whether or not antenatal prophylaxis is given. The economic issues could, however, be overcome by the fact that there is a major clinical benefit to offering the test systematically to all RhD-negative pregnant women while avoiding unnecessary testing and immunoglobulin injections.