Safety and cost-containment data that advocate abbreviated pretransfusion testing.

Abbreviated pretransfusion testing, although permitted by American Association of Blood Banks Standards for unimmunized patients, is not widely practiced. Concerns remain about optimal antibody screening methods, antibodies missed by deleting the antiglobulin crossmatch, and cost-effectiveness. The authors prospectively tested 3,380 serum samples for blood type, antibody screen, and antiglobulin crossmatch. Antibody screens for 2,000 samples, performed with the use of a two-cell screen, were compared with 1,380 samples studied with a three-cell screen. Also, all 3,380 sera had major crossmatches performed carried through the antiglobulin phase. Two and three screening cells gave comparable results, with 5.45% of patients tested by two-cell and 5.22% by three-cell screens having a positive antibody screen. Of those with negative screens, 0.5% screened by two-cell screens and 0.8% by three-cell screens had a positive major crossmatch. Among these (negative antibody screen, positive crossmatch), only 0.03% (1 of 3.380) had a clinically significant alloantibody (anti-Kpa); 0.27% (9 of 3,380) had antiglobulin crossmatch positive with polyspecific antisera but negative with anti-IgG; and 0.12% (4 of 3,380) had positive crossmatch because of passive anti-A. By cost accounting of labor and reagents, 84 per unit would be saved using abbreviated versus complete pretransfusion testing. Blood banks now performing complete pretransfusion testing should reconsider abbreviated crossmatching for unimmunized patients as a safe, efficacious means of cost-containment.

Multiple transfusion fail to provoke antibodies against blood cell antigens in human infants.

We conducted studies of both red cell (RBC) and leukocyte (WBC) antibody formation in infants following multiple transfusions given during the first weeks of life. Fifty-three infants received 683 RBC transfusions from 503 different donors, plus 62 platelet, 4 granulocyte, and 53 fresh-frozen plasma units during the first 4 months of life. Three hundred fifty serum samples were obtained before, during, and after the transfusions. None of the infants formed unexpected RBC antibodies when tested at 37 degrees C by a two-cell low-ionic-strength solution antibody screen that included an anti-globulin phase. Twenty posttransfusion serums were negative when tested at room temperature. Lymphocytotoxic and granulocytotoxic WBC antibodies were measured in posttransfusion serums from 13 infants, and none were found. Despite exposure to many RBC and WBC antigens, no infants produced alloantibodies against blood cell antigens. Thus, immunologically mediated transfusion reactions should be quite rare in young infants, and this study supports recommendations of the American Association of Blood Banks Standards to omit repeat RBC compatibility testing during the first 4 months of life in infants whose initial RBC antibody screens reveal no unexpected antibodies.

Sterility and quality of blood dispensed in syringes for infants.

A unit-dose system was designed to dispense precise quantities of blood in a form ready for immediate transfusion into neonatal patients. The principles were similar to those used by pharmacies to dispense individual doses of drugs. In the blood center, the precise volume of blood ordered for a neonatal patient was aspirated through a microaggregate filter into a labeled plastic syringe for dispensing to the nursery in a correspondingly labeled zip-lock plastic bag. In the nursery, the premeasured and prefiltered blood was ready for immediate infusion, and the syringe was attached directly to a mechanical infusion pump. Several experiments were performed to ensure sterility and quality of whole blood dispensed by this system. Over 300 aerobic and anaerobic cultures were performed, and it was concluded that the extra handling required to prepare syringes of blood did not lead to bacterial contamination. In addition, the quality of whole blood was maintained, for at least 6 hours, equally well in syringes as it was in blood bags stored under standard blood bank conditions when assessed by hematocrit, blood pH, and measurements of plasma potassium, glucose, lactic dehydrogenase, and free hemoglobin. Thus, unit dose dispensing offers a precise and convenient method to prepare small, accurately measured quantities of filtered, sterile, and quality blood products for neonatal patients.

Effects of hydroxyethyl starch on erythrocyte typing and blood crossmatching.

Venous blood was mixed with varying amounts of 6% hydroxyethyl starch solution in vitro and also blood samples were obtained from leukapheresis donors who had received infusions of hydroxyethyl starch. These specimens were evaluated as to the accuracy of erythrocyte typing, direct antiglobulin-testing, and antibody detection using saline, albumin, low-ionic strength saline and papain media. Specimens were stored at 4 degrees C, and testing was repeated at intervals during one week. Moderate difficulties were encountered, due to rouleaux formation, in the interpretation of typing and antibody screening in some samples that contained greater than 30 percent of the hydroxyethyl starch solution. Rouleaux formation was readily dispersed with saline and could easily be distinguished from true agglutination by microscopic examination. Although the apparent difficulties were not extreme, blood bank personnel should be alerted to the potentially misleading effects of hydroxyethyl starch on test results.