[Structural or functional relationship between immunohematology and distribution - Which elements for controlling risks?] / Lien immunohématologie-délivrance structurel ou fonctionnel ­ Quels éléments pour la maîtrise des risques ?

OBJECTIVE: Transfusion safety is based on the availability of safe and compatible blood products at the right time and to the right patient, and requires close monitoring in order to detect possible incidents. The decree of June 20th 2018, which establishes the national blood transfusion's guiding plan, states that the organization that prevails throughout the national territory is built around an inseparable link between the implementation of erythrocyte immunohematology and the labile blood products delivery by authorised structures. METHOD: The article describes the two types of the link's organization, structural or functional, used to develop the comparative risk-benefit analysis. RESULTS: The structural link, which has fewer interfaces, reduces risk situations that lead to delays in release by default of a compatible product. The cases in which a functional link may have a greater benefit than the risks generated are those related to a geographical distance between the delivery site and the patient's place of care. In these cases, a functional link is possible provided that certain organizational points are mastered. CONCLUSION: The comparative analysis shows that the structural link is to be favoured since that the coherence of the patient's care and his care path is ensured. In certain situations, mainly geographical, the functional link can have a benefit that offsets the risks generated by the new interfaces; provided that the system is secured by a real tripartite collaboration between health care institution, biology laboratory and delivery site.

Relevance and costs of RHD genotyping in women with a weak D phenotype.

OBJECTIVES: For pregnant women, the serologic test results of D antigen will determine the frequency of RBC antibody detection as well as the indication for RhIG prophylaxis. RHD genotyping is the only method that may provide clear guidance on prophylaxis for women with a weak D phenotype. This analysis evaluated the economical implications of using RHD genotyping to guide RhIG prophylaxis among pregnant women with a serological weak D phenotype. METHODS: We compared the costs of 2 strategies in a cohort of 273 women with weak D phenotype. In the first strategy, we did not perform genotyping and all women with weak D phenotypes were treated as if they were D-, thus considered to be a risk of RhD alloimmunization. These women all received the prophylactic follow up. In the second strategy, RHD genotyping was performed on all women with a serologic weak D phenotype. Then, the follow-up will be determined by phenotype deduced from genotype. RESULTS: On the studied cohort, the additional expense occurred by genotyping is 26,536 €. RHD Genotyping has highlighted 162 weak D Type 1, 2 3, that could safely be managed as D+ and 111 partial D to consider as D-. By comparing the 2 strategies, the savings generated by genotyping the patients of our cohort are € 12,046 for the follow up of one pregnancy. Knowing that in France, a woman has on average 2 pregnancies and that the genotyping is carried out only once, the savings generated for the following pregnancies would be € 38,581. CONCLUSIONS: Performing RHD genotyping for pregnant women with a weak D phenotype enables to clearly identify weak D type 1, 2 or 3 from the other variants at risk of alloimmunization. This analysis generates savings in terms of follow-up schedule of pregnant women and RhIG prophylaxis. It also allows saving of D- products for patient with a weak D type 1, 2 or 3 in case of a transfusion need.

[Microtitration of anti-RH1 antibodies: interest in the follow-up of pregnant women]. / Intérêt de la technique de microtitrage des anticorps anti-RH1 dans le suivi immunohématologique des femmes enceintes.

UNLABELLED: The proposal for a 300 microg anti-RH1 injection at 28 GW by RH:-1 pregnant women complicates the interpretation of the screening for alloantibodies during pregnancy; to distinguish an alloantibody from a passive one is nevertheless important for the care of the patients. Testing a technique allowing this distinction seems thus necessary. MATERIAL AND METHODS: The technique of microtitration of anti- RH1 antibodies is an indirect antiglobulin test. Two hundred specimens were tested in comparison with a standard prepared from a national anti- RH1 standard. If the anti- RH1 concentration measured is lower or equal to the expected concentration, there is a passive antibody. If the concentration is largely higher, we can suspect an allo-immunization. RESULTS: With this technique, 38 alloanti- RH1 and 112 passive anti- RH1 antibodies were confirmed. Twenty-five diagnosis were modified: seven alloanti- RH1 initially labeled passive and 18 passive anti- RH1 previously considered as alloantibodies. 15 cases can not be concluded, because the blood sample was taking away too early after the injection, and 10 cases are on standby, waiting for a control. DISCUSSION: The microtitration is an important exam in the follow-up of the RH:-1 pregnant women when an anti-RH1 antibody is found. This exam should be offered each time we have no information about the anti-D injection, or when an incoherent reaction compared to the presumed date of injection is observed.