Positive antiglobulin tests due to intravenous immunoglobulin in patients who received bone marrow transplant

To investigate an increased frequency of positive direct (DAT) and indirect (IAT) antiglobulin tests in bone marrow transplant (BMT) patients who received intravenous immunoglobulin (IVIG), serologic testing was performed weekly on blood samples from 94 consecutive BMT patients. Group 1 (47 patients) did not receive IVIG. Group II (47 patients) received high-dose IVIG as prophylaxis for cytomegalovirus infections. Before transplantation no alloantibodies were found in the serums of 92 patients and anti-E was found in the serums of two patients. DATs were negative in all patients before BMT. Four percent of Group I had a positive IAT and 13 percent had a positive DAT. In contrast, 25.5 percent of Group II patients had a positive IAT and 49 percent had a positive DAT, usually within 1 week after initiation of IVIG therapy (p less than 0.001). Antibodies identified in serums and eluates of patients in Group I were anti-A and anti-B. Antibodies identified in serums and eluates of patients in Group II were anti-A, -B, -D, and -K. Twenty-one lots of IVIG were tested and antibodies identified were anti-A, -B, -D, and -K. The data suggest that the higher frequency of positive serologic tests in Group II was due to passively acquired antibodies from high-dose IVIG.     

Algorithms for evaluating the appropriateness of blood transfusion

Medicare regulations and the guidelines of the Joint Commission on Accreditation of Healthcare Organizations require assessment of the appropriateness of transfusions by a hospital committee. A set of criteria maps for component transfusion review by nurses or technical personnel was designed, tested, and modified. The algorithms were based on written guidelines developed by a group of physicians. In the first part of the study, 196 medical records of patients from medical and surgical diagnosis-related groups with the highest utilization of blood (Group I) were screened. Forty patients were excluded because of a preexisting transfusion protocol. Of the remaining 156 patients, 146 (94%) received red cell transfusions, of which 96 percent were indicated, 1 percent not indicated, and 3 percent controversial. Thirty-five patients (22%) received fresh-frozen plasma transfusions, of which 69 percent were indicated, 11 percent not indicated, 17 percent controversial, and 6 percent indeterminate. In the second part of the study, medical records were screened from 99 randomly selected patients who had received red cell transfusions (Group II), and the results were similar to those in Group I. Physician review was necessary in 20 percent of the transfused patients screened with the criteria maps. It is concluded that algorithms for transfusion review can be developed and used easily to fulfill regulatory and accreditation requirements and to plan focused educational programs.     

Alloimmunization in patients with warm autoantibodies. A retrospective study employing three donor alloabsorptions to aid in antibody detection

We examined the value of performing alloabsorptions to detect clinically significant alloantibodies in patients with warm autoantibodies who must receive crossmatch-incompatible blood. One hundred and twenty-five (125) patients were evaluated using alloabsorption with red cells (RBCs) from three donors: R1R1, R2R2, and rr, whose phenotypes other than Rh were selected to exclude 98 percent of clinically significant alloantibodies. This technic was selected rather than autoabsorption due to insufficient quantities of patient cells available and to the possible presence of transfused cells in some instances. Patients were divided into three risk categories: I–no prior pregnancy or transfusion; II–history of pregnancy and/or one to five transfusions; and III–greater than five transfusions. No significant alloantibodies were found in 32 category I patients. Of 74 category II patients, 13 (17.5%) had significant alloantibodies detectable after absorption. Six of 19 (31.5%) category III patients had alloantibodies. The majority showed Rh specificity: anti-E (13), -C (6), -c (2), -D (1). Anti-K was found in five samples. Forty-two (42%) percent of the alloantibodies were undetectable prior to the alloabsorptions. We conclude that category II and particularly category III patients are at significant risk of allosensitization and should be evaluated by an absorption procedure prior to the transfusion of crossmatch-incompatible red cells.     

Comparison of efficacy of packed red blood cell transfusion based on its hemoglobin content versus the standard transfusion practice in thalassemia major patients (HEMOCON study)

The hemoglobin (Hb) content of packed red blood cell (PRBC) units is heterogenous. The efficacy of a transfusion episode can be assessed if the Hb content of the PRBC is known and the patient’s post-transfusion Hb increment is also determined. This prospective study compared the efficacy of PRBC transfusion based on its Hb content versus the standard transfusion practice. A total of 160 thalassemia major patients were enrolled and randomly divided into two equal groups: Group I (n = 80) – they received ABO/RhD identical PRBCs after determining its Hb content (≥50 g); and Group II (n = 80) – they received randomly selected ABO/RhD identical PRBCs. Hb estimation and a direct antiglobulin test were performed on the post-transfusion sample (1 h). The mean Hb content of the PRBC units was significantly higher (p = 0.000) in group I (67.86 ± 8.07 g; range: 50.80–92.13 g) than group II (60.92 ± 8.29 g; range: 40.86–86.76 g). The mean Hb increment was also significantly higher in group I patients (p = 0.04). In both the groups, there was a significant negative correlation between Hb increment and weight, age, body surface area and blood volume (p < 0.05). There was a significant positive correlation between Hb increment and Hb dose adjusted for body surface area as well as blood volume (p < 0.05). PRBC transfusion was more efficacious in patients who were transfused with PRBCs having a Hb content ≥50 g as compared to those who received randomly selected PRBCs.     

Revisiting the issue: can the reading for serologic reactivity following 37°C incubation be omitted?

BACKGROUND: Omitting the 37 degrees C reading from screening tests for unexpected antibodies results in failure to detect some Rh, K, and Jk agglutinins of potential significance (wanted positives). However, this measure avoids unwanted positive tests due to cold agglutinins. STUDY DESIGN AND METHODS: Using data from prior publications, actual risk calculations (ARCs) were made to predict the risk of eliminating the 37 degrees C reading, pretransfusion direct antiglobulin test (DAT), and routine indirect antiglobulin crossmatch (IAT-XM). ARCs used the equation: wanted positives missed x 0.34 (or 0.80) x 5 x percent antigen-positive, where 0.34 = percent of patients transfused (ARCs for 37 degrees C reading and DAT); 0.80 = percent of crossmatched patients transfused (ARCs for IAT-XM); 5 = average number of units transfused. Following elimination of the 37 degrees C reading, the impact of this change on patient care was monitored. Antibody detection and identification data and transfusion reaction reports for 6 months after the change were reviewed. Recently transfused patients with new antibodies were evaluated for immune hemolysis by review of clinical and laboratory data. The findings were compared with those from the same dates of the preceding year. RESULTS: The risk of transfusing incompatible blood by eliminating the DAT, IAT-XM, and 37 degrees C reading is approximately 1:13,000, 1:2,000, and 1:2,400 units transfused, respectively. The cumulative risk from eliminating all three tests is approximately. 1 :1,000 units. With respect to the 37 degrees C reading, there were no differences between the pre-change and post-change study periods in the incidence of reported transfusion reactions or cases of immune hemolysis associated with newly formed antibodies. However, unwanted positive tests decreased from 162 to 61 following elimination of the 37 degrees C reading. This represents a decrease of 20 percent in the number of samples requiring antibody identification annually. CONCLUSIONS: Eliminating the 37 degrees C reading from pretransfusion antibody screening tests imposes less risk than omitting the routine IAT-XM, and it avoids the time and costs of evaluating unwanted positive tests, thus reducing expenditures and delays in patient care.     

Direct antiglobulin tests in narcotic addicted patients

Direct Antiglobulin Tests (DAT) as well as a number of immunological parameters (immunoglobulin levels, latex fixation, VDRL) were studied in 168 narcotic-addicted patients. Of these, 94 were untreated narcotic addicts (Group I), 61 were methadone maintained patients (Group II), and 13 had completed successful detoxification with methadone and were drug-free (Group III). Weakly positive DAT were detected in 2.1 per cent of individuals in Group I, 18 per cent in Group II, and 15 per cent in Group III. The reactions were usually transient. A number of other immunological aberrations were also present in individuals of all three groups, but there was no correlation between these parameters and the positive direct antiglobulin reactions.     

非自身免疫性溶血性贫血患者直接抗人球蛋白试验阳性对临床输血效果影响

目的:研究非AIHA患者DAT阳性对临床输血效果影响.方法:收集多个科室96例DAT阳性的非AIHA输血者为阳性组,均分为甲组(48例输注洗涤红细胞)和乙组(48例输注普通红细胞悬液),对照组为58例DAT阴性的常规输血患者.采用微柱凝胶法(MGT)和凝聚胺法进行交叉配血.检测患者红细胞(RBC)、血红蛋白(Hb)、红...     

Viral serology (hepatitis B virus, cytomegalovirus, Epstein-Barr virus) and abnormal liver function tests in transfused patients with hereditary hemorrhagic diseases

Posttransfusion hepatitis and asymptomatic liver disease remain serious and unresolved problems in transfused patients with hereditary hemorrhagic diseases. We studied the occurrence of antibody and antigen to hepatitis B virus (anti-Hbs and HBsAg) as well as antibody to cytomegalovirus (anti-CMV) and Epstein-Barr virus (anti-EBV) in this population and correlated this with liver function tests. The study population was divided into two groups: Group I, consisting of 35 patients (moderate to mild disease) requiring less than 12 transfusions per year and Group II, consisting of 38 patients (severe disease) requiring more than 12 transfusions per year. Frequency of transfusion correlated with detectable anti-HBs and anti-CMV (48.6% and 25.7% in Group I, 94.7% and 47.4% in Group II). Three patients, all in Group I, were HBsAg positive while none in Group II had demonstrable antigen. Anti-EBV occurred with similar frequency in both groups. The abnormal liver funtion tests present in 62.9 per cent of Group I and 89.5 per cent of Group II correlated poorly with the presence of anti-HBs, anti-CMV and anti-EBV. Splenomegaly was not detected in any of the 73 patients. HBV and CMV appear to be transmissible by transfusion, and other viruses such as non-A, non-B may account for this liver dysfunction.     

RBC autoantibodies in autoimmune lymphoproliferative syndrome

BACKGROUND: Patients with autoimmune lymphoproliferative syndrome (ALPS) have an autosomal dominant genetic defect that affects lymphocyte apoptosis and is associated with chronic nonmalignant lymphadenopathy, splenomegaly, and autoimmunity, particularly affecting RBCs, WBCs, and platelets. STUDY DESIGN AND METHODS: DATs were performed on 34 consecutive patients with ALPS and 37 of their clinically unaffected relatives. The effects of age, sex, race, and immunoglobulin levels on the incidence of autoantibodies and clinical hemolysis were assessed. RESULTS: The DAT was positive in 21 (62%) of ALPS patients but in only 1 (3%) of their relatives (p = 0.001). The DAT reacted because of IgG alone in 43 percent, complement alone in 5 percent, and IgG plus complement in 19 percent; 33 percent of the patients' cells had a positive reaction with polyspecific reagent only. All 10 ALPS patients with a history of hemolytic anemia had a positive DAT. Sixty percent of them had only IgG on their cells, 30 percent had IgG and complement, and 10 percent reacted only with polyspecific reagent. Of the 11 patients with a positive DAT and no history of hemolytic anemia, IgG alone was present in 27 percent, complement alone in 9%, and IgG plus complement in 9 percent; 55 percent had positive DATs only with polyspecific reagent. Among ALPS patients, those with a positive DAT had greater quantities of cells with increased alpha and ss T-cell receptors that phenotyped as CD4-CD8- and higher IgG levels. CONCLUSIONS: The DAT results in ALPS patients are most similar to those found in warm autoimmune hemolytic anemia. The DAT is useful to distinguish affected and unaffected persons within an ALPS family.     

The evaluation of a positive direct antiglobulin test in pretransfusion testing

The results of serologic studies on 879 blood samples with a positive direct antiglobulin test (DAT) are presented. All blood samples were from patients who were either anemic, for reasons other than blood loss, recently transfused, or had serum antibodies detected during routine pretransfusion tests. Blood samples from only 81 of the patients included in this study had serologically reactive eluates (64 autoantibodies, three antibodies to penicillin and cephalothin treated red blood cells, three passively acquired anti-A antibodies, and 11 transfusion-induced alloantibodies). The eluted antibodies were also detected in the serum by routine pretransfusion tests in 13 of the patients whose red blood cells eluted autoantibodies, and in five of the patients whose red blood cells eluted transfusion-induced alloantibodies. All but one of the 11 transfusion-induced alloantibodies were detected within 14 days posttransfusion. Based on these findings, a cost-effective and safe approach to the management of blood samples with a positive DAT would be to restrict the preparation and testing of eluates to those samples from recently transfused patients. It is the contention of the authors that the incorporation of the DAT in pretransfusion testing should primarily serve to detect alloantibody formation before such antibodies are evident in the serum, and should not be used to screen patients for unsuspected autoimmune hemolytic anemia. Furthermore, the authors question the necessity for blood banks to routinely perform an autocontrol on all blood samples from prospective transfusion recipients.     

The evaluation of a positive direct antiglobulin test (autocontrol) in pretransfusion testing revisited

Direct antiglobulin tests (DATs) using anti-IgG were performed on 65,049 blood samples from prospective transfusion recipients; 3570 tests (5.49%) were positive. Using criteria published previously (primarily excluding patients not transfused within the preceding 14 days), 778 samples from other than neonatal patients were selected for further evaluation. Eluates that did not react were obtained on 518 (66.6%) of these samples. Warm-reactive autoantibodies were apparent in 192 eluates, while 16 contained drug-related antibodies, anti-A or anti-B from prior transfusion with ABO mismatched blood components, or anti-D passively acquired from immune serum globulin. Fifty-two eluates contained alloantibodies; however, in only six of these cases did the corresponding serum lack unexpected alloantibodies, as determined by routine pretransfusion studies. Three additional weakly reactive clinically significant alloantibodies were detected solely through additional serum tests performed on DAT-positive samples. On the basis of these findings, the DAT had a low predictive value when used to detect the early manifestations of an immune response to recently transfused red cells. Elimination of the autocontrol from routine pretransfusion testing, therefore, carries minimal risk to patients yet will undoubtedly contribute to the containment of health care costs. Moreover, the risk is lower than that associated with the elimination of the antiglobulin crossmatch.     

Experience with donors matched for minor blood group antigens in patients with sickle cell anemia who are receiving chronic transfusion therapy

Clinically significant alloimmunization to red cell antigens occurred in 28 percent of transfused patients in a sickle cell clinic. Therefore, a prospective study was undertaken to determine whether matching donors carefully for 17 blood group antigens would diminish the risk of further alloimmunization in patients on a chronic transfusion program. Alloantibodies had developed previously in 8 of the 12 patients. After chronic transfusion with selected donors, four new antibodies developed in three patients. Three antibodies were due to errors in phenotyping or matching, and one was due to an antigen that was not tested for in the protocol. The incidence of developing antibodies per unit transfused was diminished tenfold when selected donors were used. Autoantibodies developed in five patients (42%), but these did not seriously interfere with the transfusion therapy. It was concluded that matching for red cell antigens may diminish the incidence of alloimmunization in patients with sickle cell anemia requiring transfusion.     

A flow cytometric method for phenotyping recipient red cells following transfusion

BACKGROUND: Reticulocyte phenotyping is used for transfused patients, who have red cell antibodies, to match blood for subsequent transfusion. Current methods are labor-intensive and require a significant amount of sample. STUDY DESIGN AND METHODS: A simple dual- color flow cytometry method developed for antigen typing of reticulocytes in mixed red cell populations is reported. Antigens were labeled by an indirect immunofluorescence technique using undiluted reagent sera as the primary label, biotinylated goat anti-human IgG as the secondary label, and avidin-phycoerythrin as the fluorescent stain. Reticulocytes were labeled with a thiazole orange fluorescent stain. Reticulocyte identification and antigen typing were performed on 319 samples to establish the validity of the procedure. Mixed red cells were prepared in all possible c antigen combinations to simulate transfusion concentrations of 25, 50, and 75 percent. RESULTS: The anti- c flow cytometry profiles readily distinguished between antigen- positive and antigen-negative populations and allowed the detection of reticulocytes at all simulated transfusion concentrations. Similar results were obtained in experiments using C, K, s, Fya, Fyb, Jka, or Jkb sera against equal volumes of antigen-positive and -negative cells. Anti-S gave inconsistent results. The in vitro results were confirmed in 19 transfused patients who had received red cells antigenically different from their own as well as cells from 1 chimera blood donor. CONCLUSION: This method provides a simpler, safer, less labor- intensive, and less subjective technique requiring far less sample volume than current methods for antigen typing of reticulocytes in mixed red cell samples from recently transfused patients.     

The differentiation of delayed serologic and delayed hemolytic transfusion reactions: incidence, long-term serologic findings, and clinical significance

Delayed serologic transfusion reactions (DSTRs) and delayed hemolytic transfusion reactions (DHTRs) were studied in a large tertiary-care hospital. A DSTR was defined by the posttransfusion finding of a positive direct antiglobulin test (DAT) and a newly developed alloantibody specificity. A DHTR was defined as a DSTR case that showed clinical and/or laboratory evidence of hemolysis. Thirty-four cases of DSTR, 70 percent of which were due to anti-E and/or -Jka, were documented prospectively over a 20-month period. Retrospective review of the medical records found clinical evidence of hemolysis in only 6 (18%) of the 34. Thus, the incidence of DSTR was 1 (0.66%) of 151 recipients with posttransfusion samples available for testing, whereas the incidence of DHTR was only 1 (0.12%) of 854 patients tested. Fifteen of the 34 patients were followed for up to 174 days after reaction. Twelve of the 15 still demonstrated a positive DAT with anti-IgG only. Eluate studies indicated that the persistence of a positive DAT after DSTR or DHTR may involve several immunologic mechanisms, including the development of posttransfusion autoantibodies. This study indicates 1) that DSTRs are a frequent finding in multiply transfused patients, although most cases are benign and fail to meet rigid criteria for DHTR, and 2) that the persistence of a positive DAT after DSTR or DHTR is common.     

Iron stores in remunerated blood donors as evaluated by plasma ferritin levels

This study was undertaken to investigate body iron stores in so-called remunerated blood donors as well as to evaluate the sensitivity of hemoglobin determination in detecting iron deficiency in two populations of blood donors. The authors studied 522 male donors who were divided into three groups: Group I, first-time volunteer donors with hemoglobin levels greater than or equal to 13 g per dl; Group II, remunerated donors with hemoglobin levels greater than or equal to 13 g per dl; and Group III, remunerated donors rejected because their hemoglobin levels were less than 13 g per dl. Iron stores were evaluated with an enzyme-linked immunosorbent assay for plasma ferritin. In Group I, 4.5 percent were iron-deficient with a mean ferritin value of 55.3 ng per ml; in Group II, 59.7 percent were iron deficient with a mean ferritin level of 17.4 ng per ml, and in Group III, 82.5 percent were iron-deficient and the mean ferritin level was 8.4 ng per ml. The last values represent the highest percentage of iron deficiency and the lowest mean ferritin value thus far reported. In Group I, hemoglobin determination had a sensitivity of 95 percent in detecting iron deficiency, but in Group II had only 40 percent sensitivity. These results indicate that a more accurate and reliable test, such as a plasma or serum ferritin determination, may be necessary to detect iron deficiency in blood donors when they donate more than five times per year, particularly those who are remunerated.     

Blood donor-, apheresis-, and transfusion-related activities: results of the 1991 American Association of Blood Banks Institutional Membership Questionnaire

Approximately 2154 regional blood centers and hospital-based blood banks and transfusion services responded to the 1991 American Association of Blood Banks Institutional Membership Questionnaire that elicited data from 1990. Information from 2144 institutions was considered valid. Questionnaire topics were donor blood collections, hemapheresis, perioperative cell salvage, component usage, and transfusion-associated diseases. Institutional members reported collecting 9.3 million units, of which 90.9 percent were for allogeneic use in the community, 6.0 percent were for autologous use, and 3.1 percent were directed donations. The percentage of directed-donor units that were crossed over for allogeneic use (51%) was greater than the percentage of units transfused to the designated patient (49%). Only 12.5 percent of institutions reported obtaining specific consent for transfusion. Of the 15.4 million transfused blood components, 8.5 million were red cells, 4.1 million were platelets, 1.8 million were fresh-frozen plasma, and 0.9 million were cryoprecipitate. There were 1263 reported cases of transfusion-associated hepatitis. Approximately 44 percent of the patients who were tested proved positive for hepatitis B surface antigen, and 80 percent of the patients who were tested proved positive for antibody to hepatitis C. The questionnaire's aggregate results can be used to assess current patterns of blood donation and transfusion activities.     

Clinical application of a flow cytometric direct antiglobulin test

BACKGROUND: The clinical application of flow cytometric direct antiglobulin test (FC-DAT) has rarely been evaluated for patients with various diseases including immune and nonimmune hemolytic anemia.
STUDY DESIGN AND METHODS: Blood samples from 380 patients with a variety of diseases were studied using the tube direct DAT and FC-DAT. The results of tube DAT and FC-DAT were compared. The predictive values of DAT for hemolysis were evaluated.
RESULTS: Of 57 patients with autoimmune hemolytic anemia (AIHA), 6 of the 17 with a negative tube DAT (immunoglobulin G [IgG]) had a positive FC-DAT (IgG) and 23 of the 36 patients with a negative tube DAT (complement 3d [C3d]) had a positive FC-DAT (C3d). In 57 patients with AIHA, the incidence of positive results of FC-DAT (IgG) and tube DAT (IgG) were similar (42 positive vs. 40 positive); but in 323 patients without AIHA, the incidence of positive FC-DATs (IgG) was higher than that of tube DAT (IgG; 47 positive vs. 9 positive). The higher incidence of positive FC-DAT (C3d) than that of tube DAT (C3d) was seen in patients with AIHA (42 positive vs. 21 positive) as well as in patients without AIHA (61 positive vs. 5 positive). Both DAT (IgG) and DAT (C3d) positive has highest positive predictive value for hemolysis, followed by DAT (IgG) alone positive and DAT (C3d) alone positive.
CONCLUSIONS: FC-DAT is a complementary test for diagnosing AIHA. There is a synergistic effect of the red blood cell–bound IgG and complement in predicting hemolysis.     

Identifying elective orthopedic surgical patients transfused with amounts of blood in excess of need: the transfusion trigger revisited

The discharge hematocrit has been analyzed as a clinical indicator of the transfusion trigger by which to identify patients undergoing elective orthopedic surgery who were transfused with blood in excess of need. The volume of red cells lost by each patient during surgical hospitalization was compared to the volume of red cells transfused. Three clinical indicator levels were considered. Red cell losses of 10, 20, and 30 percent of each patient's baseline red cell volume at admission were considered to be appropriate before subsequent blood transfusion replacement, representing generous, intermediate, or strict clinical indicator levels, respectively. With Level I as a generous clinical indicator, 110 (25%) of 525 patients were transfused in excess of blood needs; by Level II (intermediate) and Level III (strict) criteria, 221 (42%) and 314 (60%) of 525 patients, respectively, were transfused in excess of blood needs. Significant differences were found for transfused patients analyzed by gender (26% of women vs. 13% of men; Level I, p less than 0.001) and preoperative autologous blood donation (25% of autologous blood donors vs. 11% of those who did not donate autologous blood; Level I, p less than 0.001). It can be concluded that the discharge hematocrit and amount of blood lost during hospitalization can be used as clinical indicators with which to identify patients receiving transfusions in excess of needs in the elective surgical setting. With this method, it was found that the transfusion trigger is different for women and for men as well as for autologous blood donors and those who did not donate autologous blood undergoing elective orthopedic surgery [corrected].     

Four-year survival of transfusion recipients identified by hepatitis C lookback

BACKGROUND: Information on the probability of survival of transfused patients is needed for policy making, but there is a paucity of empirical research into this question. A Swedish population-based study reported that the 40-month posttransfusion probability of survival was 51 percent in all patients and 41 percent in recipients of more than 10 units of blood and blood components. These figures were 20 percent lower than the figures reported previously from Olmsted County, Minnesota. STUDY DESIGN AND METHODS: Information was collected on the 4-year survival of 695 patients transfused at the New York University Medical Center between 1988 and 1996. These patients had been identified previously by hepatitis C lookback. RESULTS: Seventy-five percent of patients survived at 1 month after transfusion, 66 percent at 3 months, 60 percent at 6 months, 54 percent at 1 year, 50 percent at 2 years, 45 percent at 3 years, and 41 percent at 4 years. Seventy-eight percent of patients included in the study had received more than 10 units of blood and blood components. The 4-year survival of patients receiving 1 to 3, 4 to 10, or more than 10 units was 62 percent, 48 percent, and 38 percent, respectively (p < 0.0001). CONCLUSIONS: When transfusion dose is taken into account, the probability of survival of patients transfused at the New York University Medical Center in 1988 to 1996 and identified by lookback is similar to that reported for Swedish county residents transfused in 1993. Based on both the Swedish data and the information presented here and in the absence of any recent results from population-based studies, the survival of U.S. patients transfused in the 1990s appears to be 20 percent lower than that of Olmsted County residents transfused in 1981.     

Prospective evaluation of a transfusion policy of D+ red blood cells into D- patients.

BACKGROUND: Although D- patients should receive red blood cells (RBCs) from D- donors, the scarcity of D- blood components in certain situations makes the transfusion of D+ RBCs unavoidable. Therefore it is recommended that guidelines be developed in order to standardize transfusion policy in these scenarios. STUDY DESIGN AND METHODS: We have prospectively evaluated a policy for the use of D+ RBCs in 905 D- patients. The amount of D- RBCs saved as well as the incidence of hemolytic reactions and anti-D alloimmunization were assessed. RESULTS: 554 patients received D- RBCs while 351 received a total of 1032 D+ RBCs, all of them within our criteria for the acceptable use of D+ RBCs. This strategy allowed us to save 25.6 percent of D- RBCs (1032 out of 4024 RBCs requested). No hemolytic reactions were reported. The incidence of alloimmunization was 21.4 percent. Most patients who developed anti-D did so within the first 2 or 4 RBCs transfused (64% after the first 2 RBCs transfused and 88% after the first 4). In multivariate analysis the age of less than 77 years was the only predictor for alloimmuization (HR = 2.48 [95% CI = 1.21-3.81]; p = 0.014). CONCLUSION: The use of D+ RBCs in selected D- patients does not induce adverse reactions and allows the saving of a significant number of D- RBCs.