A solid phase and microtiter plate hemagglutination method for pretransfusion compatibility testing.

Most hospital blood transfusion services perform routine pretransfusion compatibility tests (ABO/D typings, antibody detection tests and crossmatches) using standard test tube methods. Recently, alternative technologies, including microtiter plate methods, solid phase red cell adherence (SPRCA) assays, gel tests, microbead columns and affinity column assays have become available. While the increased sensitivity of these new serological technologies is an important advantage, cost savings and automated testing are also important benefits. Our hospital's Transfusion Service converted from manual test tube methods for compatibility testing to manual microtiter plate and SPRCA methods and, subsequently, to automated microtiter plate and SPRCA methods. The conversion was facilitated by using commercially-marketed reagent kits and a fully-automated blood typing analyzer. The automated blood typing system was linked electronically to a hand-held combination bar code reader/portable data terminal that enabled positive identification of patients' bar code wrist bands, personal identification badges, and bar code labels on patients' blood samples and blood components. This bar code identification system has been implemented in the hospital's outpatient Infusion Service. Thus, the conversion to microtiter plate and SPRCA assays enhanced transfusion safety not only by increasing the sensitivity of serological testing, but also by standardizing compatibility testing, supporting electronic record keeping, and linking the laboratory analyzer to a bar code identification system.

Detection of multiple passively acquired alloantibodies following infusions of IV Rh immune globulin.

BACKGROUND: Passively acquired blood group alloantibodies are detected regularly after infusions of IV Rh immune globulin (RhIG) for the treatment of immune thrombocytopenic purpura (ITP) in D+ patients. STUDY DESIGN AND METHODS: Blood samples from 16 D+ patients with ITP were tested after treatment with IV RhIG for the presence of passively acquired alloantibodies. Similar studies were conducted for three D- patients after injections of IM RhIG for Rh immunoprophyl-axis. Four production lots of IV RhIG and 2 lots of IM RhIG were tested for the presence of alloantibodies. RESULTS: All 16 D+ patients with ITP developed a positive DAT, as well as positive antibody detection test results, after infusions of IV RhIG. All postinfusion plasma samples contained anti-D, as well as one or more additional antibodies, usually anti-C, -E, -G, -V, or -Fy(a). Eluates from patients' RBCs with positive DAT results contained multiple passively acquired alloantibodies. Multiple alloantibodies were detected in samples of different production lots of IV RhIG or IM RhIG. No acute transfusion reactions were observed in five D+ patients with ITP who had been treated with IV RhIG and had been given serologically incompatible D+ RBCs. After injections of IM RhIG, the only passively acquired alloantibody detected was anti-D. CONCLUSION: Plasma samples from D+ patients with ITP treated with IV RhIG regularly contained anti-D and multiple other passively acquired Rh, Duffy, or Kidd system alloantibodies. Postinfusion RBC samples all had positive DAT results with eluates containing anti-D and multiple other Rh, Duffy, or Kidd system antibodies. The consistent detection of multiple passively acquired alloantibodies after IV RhIG, in contrast to the detection of anti-D only after IM RhIG, reflects the immediate effect of the entire (bolus) dose of RhIG by the IV route, the dose for treating ITP that is approximately 10 times the dose for Rh immunoprophylaxis, and the expected serologic incompatibility with recipients' D+ RBCs.

Naturally-occurring anti-Jka in infant twins.

Anti-Jka was detected by solid-phase red cell adherence (SPRCA) antibody detection and identification tests in the plasma of a 9-month-old female infant during a routine presurgical evaluation. The patient and her nonidentical twin sister, who also had anti-Jka in her plasma, were products of an uncomplicated in vitro fertilization, full-term pregnancy, and vaginal delivery. Neither twin had been transfused, recently infected, or treated with medication. Their mother had no prior pregnancies or transfusions. Red blood cells (RBCs) from the patient and her sister typed as Jk(a-b+) by direct hemagglutination, and this phenotype was confirmed by negative adsorption and elution studies. Both infants' plasma samples were strongly reactive with 20 examples of Jk(a+) RBCs and nonreactive with 20 examples of Jk(a-) RBCs by SPRCA assays. Anti-Jka was not detected in either twins' plasma by indirect antiglobulin tests by tube method in low-ionic- strength saline solution or polyethylene glycol, or with ficin- or papain-treated RBCs. Monocyte monolayer assays using Jk(a+) RBCs sensitized by either twins' serum were nonreactive (0%). RBCs from both parents typed as Jk(a+b+). Both parents' antibody detection test results by SPRCA assay were negative. The absence of a history of exposure to allogeneic RBCs or possible passive transfer of maternal or other alloantibody classifies these antibodies as naturally-occurring anti-Jka.

Immunoprophylaxis using intravenous Rh immune globulin should be standard practice when selected D-negative patients are transfused with D-positive random donor platelets.

A 67-year-old female developed excessive bleeding and thrombocytopenia following cardiovascular surgery. Her blood type was group A, D-. The only platelet products available in the transfusion service were random donor platelet concentrates from D+ donors. She was transfused with a pool of 6 D+ random donor platelet concentrates. Anti-D undetected in her pretransfusion serum by solid-phase antibody screen was present 11 days later. Retrospectively, the patient provided a history of having two pregnancies more than 40 years ago, prior to the availability of immunoprophylaxis by Rh immune globulin (RhIG). Although studies have shown that as many as 19 percent of D- people may develop anti-D following transfusion of platelets from D+ donors, there is no specific standard requiring immunoprophylaxis with RhIG to prevent Rh alloimmunization after transfusion of random donor platelet concentrates from D+ donors. In contrast, vigorous efforts are routine for preventing Rh alloimmunization in D- patients requiring red cell transfusions or D- females during pregnancy or after delivery of D+ newborns. The absence of a comparable practice standard for platelet transfusions is based, in part, on concern that intramuscular injections of conventional RhIG may cause local hemorrhage in thrombocytopenic persons. The recent availability of a Food and Drug Administration-approved preparation of intravenous RhIG makes Rh immunoprophylaxis in thrombocytopenic patients safe and practical. We recommend that intravenous RhIG be considered if it is necessary to transfuse random donor platelet concentrates from D+ donors to D- recipients. As a minimal standard, intravenous RhIG should be administered to all D- females of childbearing age who are recipients of pools of random donor platelet concentrates from D+ donors.