Giving Rh immune globulin to these women is not harmful.Īll women, regardless of their D type, should be tested during each pregancy for clinically significant antibodies, ideally at their first obstetrician visit. The clinical implication of this change is that a few women who actually have weak expression of the D antigen will be classified as Rh negative and will be candidates for Rh immune globulin. All women are now typed as either Rh negative or positive. The main reason is that today’s blood typing reagents are much more potent and most of the patients who were previously typed as weak D are now typed as Rh positive. The AABB has determined that weak D testing is no longer necessary for obstetric patients. Historically, if a patient typed as Rh negative, additional testing was then performed to determine if they had weak D expression. Serologic confirmation of the D type is also recommended at the beginning of each subsequent pregnancy. This recommendation is especially important as a safeguard to prevent an Rh negative woman from being falsely typed as Rh positive and denied RhIG. A record of the maternal ABO type is also helpful should the newborn infant develop signs and symptoms consistent with ABO HDN.ĭ typing should be done on at least two separate occasions and the results should be identical. Any discrepant results must be fully investigated. The results should not conflict with historical records. ABO typing is done primarily for patient identification. Repeat at 2-4 week intervals if below critical titerĪll women should be tested for ABO and D as early as possible in pregnancy, preferably during their first trimester visit. Rh or other clinically signficant antibody In AS-negative patients, IS crossmatch is as safe as conventional AHG crossmatch and can, therefore, replace conventional AHG crossmatch protocol.Īnti-human globulin immediate-spin crossmatch pretransfusion testing red blood cell transfusion type and screen.3 rd trimester if history of antibodies or transfusion There was no clinical or serological sign of hemolysis in the patient. Anti-P1 alloantibody was identified in one patient who was transfused two IS crossmatch compatible units but later both units were incompatible on AHG crossmatch. 99.7% IS compatible red cell units were also compatible on posttransfusion AHG crossmatch. Any incompatible AHG crossmatch was followed up as suspected transfusion reaction.Ī total of 5023 red cell units were transfused to 2402 patients with negative AS. AHG crossmatch was performed posttransfusion for all red cell units. The patients were transfused IS compatible red cell units. Pretransfusion testing comprised blood grouping and AS followed by IS crossmatch, at the time of issue of red cell unit. This prospective longitudinal study was conducted on over 5000 red cell units transfused to AS-negative patients admitted to the hospital. The present study omits conventional anti-human globulin (AHG) crossmatch and replaces it with immediate-spin (IS) crossmatch as part of pretransfusion testing in AS-negative patients to study the safety and effectiveness of IS crossmatch in recipients.
The US Food and Drug Administration and American Association of Blood Banks approved the type and screen approach in 1980s, long after antibody screen (AS) was introduced in 1950s.
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