Genotyping provided a more accurate antigen status than phenotyping patient RBCs. Patients requiring long-term transfusion support benefit from antigen matching when matching less than four antigens. Ultimately, the decision to genotype or use thiol-treated RRC antibody investigations will vary for each hospital blood bank.
A 10-year-old male with acute leukemia presented with post-chemotherapy anemia. During red cell transfusion, he developed hemoglobinuria. Transfusion reaction workup was negative. Drug-induced immune hemolytic anemia was suspected because of positive direct antiglobulin test, negative eluate, and microspherocytes on smear pre- and post-transfusion. Drug studies using the indirect antiglobulin test were strongly positive with trimethoprim and trimethoprim-sulfamethoxazole but negative with sulfamethoxazole. The patient recovered after discontinuing the drug, with no recurrence in 2 years. Other causes of anemia should be considered in patients with worse-than-expected anemia after chemotherapy. Furthermore, hemolysis during transfusion is not always a transfusion reaction.
T he video clip is a demonstration of how hospital transfusion service staff uses an online cloud-based search engine to find blood with desired antigennegative attributes. This blood center-developed tool, termed Antigen Query, provides hospital transfusion services the ability to look up historical antigen-negative data on the blood in their inventory. The functionality largely relies on mass-scale red cell genotyping of blood. 1,2The process begins with entering patient demographics into an online form. Next, staff scans ISBT 128 unit numbers to create an online worksheet that is sent electronically to the blood center. Completing and submitting the prompts takes approximately 5 minutes. The algorithm used by the blood center identifies those units with antigen-negative attributes. An electronic table is then returned to the user that displays the antigen information. The search identifies the units with antigen-negative attributes up to the desired number of units requested. If the search is unsuccessful or only partially successful, another search can be performed using other units or an order can be placed directly with the blood center. Units with antigen-positive attributes are displayed to exclude them from additional antigen-negative searches.
BACKGROUND: The provision of units with antigennegative attributes is required for alloimmunized transfusion recipients and to avoid alloimmunization among patients on chronic transfusion support. Recent evidence confirms that the demand for antigen-typed units is increasing.
STUDY DESIGN AND METHODS:A cloud-based search engine was designed by the blood center to find antigen-negative units. The service provided access to historical antigen information for units in hospital inventories. The hospital transfusion service was required to confirm the antigen phenotype. The results of 16 hospitalsʼ use over 5 years were analyzed to determine trends and value of the service. The time commitment of the cloud-based query was compared to the hospital performing manual phenotyping with an outcome of at least one unit found with the desired antigen-negative attribute(s).RESULTS: Hospitals were located between 4 miles and 200 miles away from the blood center. A total of 6,081 queries were submitted over the 5 years, with an overall 50% success rate of finding at least one unit. Single antigen queries accounted for 67% of total searches, with two antigen queries and three or more antigen queries accounting for 24% and 9% of the units found, respectively. The cloud-based antigen query was most efficient for combined antigen frequencies <0.5 for two or more antigen-negative attributes.CONCLUSION: A cloud-based search engine provides hospitals with access to historical antigen information housed at the blood center. Future refinements may consider regulatory submission of a process to provide confirmed historical information through this cloud-based program.From the
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