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Procoagulant effect of incompatible platelet transfusions in alloimmunized refractory patients.

The clinical effectiveness of platelet transfusion in refractory patients is still a subject of debate. We have evaluated the possible hemostatic effect of platelet transfusion in 16 alloimmunized thrombocytopenic patients whose platelet counts were less than 20,000/microliters. Platelet concentrates were always obtained by apheresis procedures from incompatible donors. The posttransfusion platelet recovery was greater than 15% only in 3 cases. In the first 6 patients, measurements of bleeding time performed immediately before transfusion were in all cases longer than 30 min and did not change significantly 10 and 60 min after platelet transfusions. In all patients, ex vivo perfusion experiments with Baumgartner's platelet adhesion model, using native nonanticoagulated blood, were performed immediately before and 10 and 60 min after transfusion. No difference in platelet deposition onto the subendothelial surface was observed after platelet transfusion. Unexpectedly, the deposition of fibrin on the subendothelial surface was statistically augmented in the posttransfusion studies. Quantification of thrombin-antithrombin complexes (TAT) in plasma showed statistically significant elevations (p < 0.01) in the posttransfusion samples (31.9 +/- 12.6 vs. baseline 5.8 +/- 1.7 ng/ml), not justified by TAT levels in the transfused material (2.3 +/- 0.17 ng/ml). Transfusion of incompatible platelets to refractory patients may activate coagulation mechanisms in the absence of an increase in peripheral platelet count.

Blood Group Incompatibility↗

Retrograde transmission of Proteus mirabilis during platelet transfusion and the use of arbitrarily primed polymerase chain reaction for bacteria typing in suspected cases of transfusion transmission of infection.

BACKGROUND: When bacteria are found, after a platelet transfusion, in the recipient's blood as well as in the platelet concentrate (PC), a causal relationship is normally suspected, with the PC as the causative agent. The other alternative, that the patient has bacteremia and contaminated the PC, is less well documented in the literature. CASE REPORT: Arbitrarily primed polymerase chain reaction (AP-PCR) was used for testing strains of Proteus mirabilis isolated from a patient's blood before and after a platelet transfusion and from the PC. Because of a febrile reaction after a platelet transfusion, bacterial culture was performed on the PC used, showing growth of P. mirabilis. The same species was found in the patient's blood after the transfusion. Posttransfusion sepsis caused by a contaminated PC was suspected, and anti-sepsis treatment was given to the recipient. Later, it became apparent that the patient had had bacteremia before the transfusion and that P. mirabilis was one of the species in the isolate. With AP-PCR, the identity of the three P. mirabilis isolates could be distinguished. CONCLUSION: AP-PCR is a useful technique for distinguishing the identity of bacterial isolates from patients and blood components. A patient with bacteremia can contaminate a PC in conjunction with a platelet transfusion. With AP-PCR, the PC could be ruled out as the cause of the posttransfusion sepsis.

Base Sequence↗

Alloimmunisation to platelet transfusions in the Indian patients.

Twenty nine patients of acute and chronic leukemia undergoing chemotherapy and receiving blood transfusions (BT) and platelet transfusions (PT) from random donors (3-20 PT from 4-56 donors) were followed up for alloimmunisation using the platelet immunofluorescence test. Two women patients aged 65 and 28 yr reacted positive. Both patients had received multiple BT but no PT at the time of testing. Both were parous women. Our results point to the need to test for alloimmunisation prior to starting PT in parous women who have received multiple BT, although a study on larger number of patients is necessary for confirmation.

Adolescent↗

Lowering the prophylactic platelet transfusion threshold: a prospective analysis.

The 20 x 10(9) /L threshold for prophylactic platelet transfusion may be unnecessarily high. Few prospective studies, however, in which other trigger values were tested have been published. In this study all hospitalized, thrombocytopenic adult hematology-oncology patients in our institution were prospectively evaluated daily for hemorrhage and platelet transfusion during a one year period; no patients were excluded for bleeding or infectious problems. By design, during the initial six-months (baseline period), the prophylactic platelet transfusion trigger was 20 x 10(9) /L; for the second six-months (study period) this threshold was changed to 10 x 10(9) /L. Patients studied during the two periods did not differ significantly in age, gender, diagnosis, blood or marrow transplant status, and duration of neutropenia. Compliance with the thresholds was 95.6% (baseline period) and 93.5% (study period). For patients with platelet counts under 20 x 10(9) /L, the mean use of platelet transfusions per patient per day was significantly lower in the study period (4.47) than in the baseline period (6.48; p<0.001). Both mean prophylactic (1.54/patient-day) and therapeutic (2.93/patient-day) platelet transfusions were reduced in the study period compared with the baseline period (2.26 and 4.22/patient-day, respectively). Hemorrhage was slightly reduced in the study period compared with the baseline period: major hemorrhage, 15.2% vs. 18.4% (p=0.014); minor hemorrhage, 63.6% vs. 70.1% (p<0.001). Thus, hemorrhage was not increased with the lower trigger level. A 10 x 10(9) /L prophylactic platelet transfusion threshold value is safe and effective.

Adult↗

A randomized trial of washed red blood cell and platelet transfusions in adult acute leukemia [ISRCTN76536440].

BACKGROUND: Platelet transfusion is universally employed in acute leukemia. Platelet concentrate supernatants contain high concentrations of biologic mediators that might impair immunity. We investigated whether washed platelet and red cell transfusions could improve clinical outcomes in adult patients with acute leukemia. METHODS: A pilot randomized trial of washed, leukoreduced ABO identical transfusions versus leukoreduced ABO identical transfusions was conducted in 43 adult patients with acute myeloid or lymphoid leukemia during 1991-94. Primary endpoints to be evaluated were platelet transfusion refractoriness, infectious and bleeding complications and overall survival. RESULTS: There were no significant differences in infectious or major bleeding complications and only one patient required HLA matched platelet transfusions. Minor bleeding was more frequent in the washed, leukoreduced arm of the study. Confirmed transfusion reactions were more frequent in the leukoreduced arm of the study. Overall survival was superior in the washed arm of the study (40% versus 22% at 5 years), but this difference was not statistically significant (p = 0.36). A planned subset analysis of those </=50 years of age found that those in the washed, leukoreduced arm (n = 12) had a 75% survival at five years compared with 30% in the leukoreduced arm (n = 10) (p = 0.037) CONCLUSION: This study provides the first evidence concerning the safety and efficacy of washed platelets, and also raises the possibility of improved survival. We speculate that transfusion of stored red cell and platelet supernatant may compromise treatment, particularly in younger patients with curable disease. Larger trials will be needed to assess this hypothesis.

Journal Article↗

Clinical consequences of alterations in platelet transfusion dose: a prospective, randomized, double-blind trial.

BACKGROUND: The dose-response relationship for platelet transfusion has become increasingly important as the use of platelet transfusion has grown. STUDY DESIGN AND METHODS: One hundred fifty-eight prophylactic apheresis platelet transfusions were administered to 46 patients undergoing high-dose therapy followed by hematopoietic progenitor cell transplantation in a prospective, randomized, double-blind, multiple-crossover study. Transfusions were administered in pairs, differing only in platelet content. Each pair consisted of a lower-dose platelet component (LDP) and a higher-dose platelet component (HDP) administered in random order to the same patient. LDPs contained a mean of 3.1 x 10(11) platelets (range, 2.3-3.5 x 10(11)), and HDPs contained a mean of 5.0 x 10(11) platelets (range, 4.5-6.1 x 10(11)). Patients with active bleeding and those who were refractory to platelet transfusions were excluded. RESULTS: The mean posttransfusion platelet count increment with LDP was 17,010 per microL, and that with HDP was 31,057 per microL (p<0.0001). Only 37 percent of LDPs resulted in platelet count increments of at least 20,000 per microL, whereas 81 percent of HDPs resulted in increments above this level (p<0.0001). The mean transfusion-free interval with LDP was 2.16 days, whereas that with HDP was 3.03 days (p<0.01). Administration of LDPs was associated with a 39 to 82 percent increase in the relative risk (per day) of requiring subsequent platelet transfusions (p<0.0001). CONCLUSION: As compared to the administration of HDPs, the administration of LDPs for prophylactic transfusion in hematopoietic progenitor cell transplant patients results in a lower platelet count increment, a lower likelihood of obtaining a posttransfusion platelet increment >20,000 per microL, a shorter transfusion-free interval, and a greater relative risk per day of requiring additional transfusions.

Adolescent↗

Platelet transfusions in infants with necrotizing enterocolitis do not lower mortality but may increase morbidity.

OBJECTIVE: Necrotizing enterocolitis (NEC), a serious multisystemic inflammatory disease most commonly seen in premature neonates, is often associated with thrombocytopenia. Infants with severe forms of NEC commonly have platelet counts of less than 50,000/mm(3), occasionally less than 10,000/mm(3). Despite an absence of data to support the practice, platelet transfusions are commonly used to maintain a certain arbitrary platelet count in an effort to prevent bleeding. As platelet transfusions contain a variety of bioactive factors including pro-inflammatory cytokines, we hypothesized that a higher number and volume of platelet transfusions would not be associated with an improvement in mortality or morbidity. STUDY DESIGN: A retrospective cohort analysis was conducted of the medical records of all infants between 1997 and 2001 with Bell's Stage 2 or 3 NEC associated with platelet counts of <100,000/mm(3). The medical records were evaluated for the following variables: platelet counts, number and volume of platelet transfusions, symptoms of bleeding, and hospital course. Mortality and development of short bowel syndrome and/or cholestasis were correlated to the total number and volume (total ml and ml/kg) of platelet transfusions. Differences between the outcome groups were compared using the independent t-test, Fisher's exact test and Mann-Whitney tests. RESULTS: A total of 46 infants met the study criteria (gestational age 28+/-4 weeks and birth weight 1166+/-756 g, mean+/-SD). There were a total of 406 platelet transfusions administered to the study population. Of these, 151 (37.2%) were given in the presence of active bleeding, with 62% of these resulting in the cessation of bleeding within 24 hours. Other listed indications for platelet transfusions were hypovolemia and severe thrombocytopenia. On analysis of the entire cohort, there was no statistical improvement in either mortality or morbidity (short bowel syndrome and cholestasis) with greater number and/or volume of platelet transfusions. Furthermore, we found that infants who developed short bowel syndrome and/or cholestasis had been given a significantly higher number and volume of platelet transfusions when compared to those who did not have these adverse outcomes [median (minimum - maximum) - number of transfusions : 9 (0 to 33) vs 1.5 (0 to 20), p=0.010; volume of transfusions (ml/kg): 121.5 (0 to 476.6) vs 33.2 (0 to 224.3), p=0.013]. CONCLUSION: This retrospective analysis suggests that greater number and volume of platelet transfusions in infants with necrotizing enterocolitis are associated with greater morbidity in the form of short bowel syndrome and/or cholestasis without the benefit of lower mortality.

Cholestasis↗

Platelet transfusion therapy: from 1973 to 2005.

Platelet transfusions are indispensable for supportive care of patients with hematological diseases. We describe the developments in platelet products for transfusion since the 1970s, when, in particular, support for patients with allo-antibodies against human leukocyte antigens was a laborious exercise with a high failure rate. Currently, due to many stepwise innovations, platelet transfusions are of low immunogenicity and sufficiently available, they have a shelf life up to 7 days, and even matched platelets can often be routinely delivered, provided that there is good communication between all partners in the chain. Future improvements can be expected from uniform type and screen approaches for immunized patients and cross-matching by computer. For efficient use of health care resources, blood banks and stem cell donor banks could share their typed donor files.

Blood Banks↗

Management of patients with hematologic malignancies and aplastic anemia who are refractory to platelet transfusions.

Patients with hematologic malignancies or aplastic anemia may have reduced responses to platelet transfusions after multiple transfusions of standard red blood cells or platelet components. This situation, conventionally described as 'refractoriness' to platelet transfusions, may result from immune or non-immune causes. Non-immune causes include fever, infections, hypersplenism, disseminated intravascular coagulation, antibiotics, or veno-occlusive disease. Immune causes include platelet-reactive alloantibodies, which are typically antibodies to human leukocyte antigens (HLA) or, less commonly, antibodies to human platelet antigens (HPA). Transfused HLA-matched platelets often have satisfactory posttransfusion survivals, but few transfusion services have the donor and logistical resources to sustain a prolonged course of platelet transfusions requiring four-antigen matches. The availability of commercially marketed kits for crossmatching samples of potential donors' platelets with a recipient's serum has facilitated donor-recipient matching. Also, platelet crossmatching may be used to select a suitable unit of from several candidates platelets that have been identified to be partial HLA matches. The high likelihood of decreased efficacy of platelet transfusions in HLA-alloimmunized recipients makes avoidance of exposure to HLA-bearing leukocytes a priority. This goal is facilitated by lowering transfusion 'triggers' for cellular blood components, particularly for prophylactic platelet transfusions, by reducing the leukocyte content of components by leukocyte-reduction filters and, possibly by ultraviolet-B irradiation of leukocyte-containing products.

Anemia, Aplastic↗

Platelet transfusion refractoriness caused by a mismatch in HLA-C antigens.

BACKGROUND: HLA-C antigens have been thought to be of little significance in determining the efficacy of platelet transfusions. However, six alloimmunized patients were encountered who were refractory to platelet transfusions because of anti-HLA-Cw3, -Cw3, -Cw7, or -Cw8. STUDY DESIGN AND METHODS: Between 1995 and the present, 88 patients with hematologic malignancies became refractory to random-donor platelet transfusions due to HLA antibodies. HLA-A- and HLA-B-compatible platelet transfusions were successful in boosting platelet levels with 82 of the patients. This study concerns the remaining six HLA-immunized patients who were refractory to HLA-A- and HLA-B-compatible platelet transfusions. The response to the platelet transfusions was assessed by calculating both 1- and 24-hour posttransfusion CCIs for each transfusion. RESULTS: The average CCI(1 hour) and CCI(24 hours) in all patients were 20.0 and 12.8 for HLA-A-, HLA-B-, and HLA-C-compatible transfusions and were 1.4 and 1.2 for HLA-A- and HLA-B-compatible but HLA-C-incompatible transfusions, respectively (p < 0.001). CONCLUSION: These findings clearly indicate that matching of the HLA-C antigens is also required in some alloimmunized patients to obtain the effectiveness of platelet transfusions.

Adolescent↗

Platelet transfusions: utilization and associated costs in a tertiary care hospital.

We implemented a prospective study to evaluate platelet transfusion utilization, resource use, and costs in a tertiary care hospital over a 6-month period. All hospitalized patients receiving platelet transfusions between July and December 1996 were followed prospectively to determine platelet use and costs. Clinical and financial data were collected, evaluated, and compared to identify trends in resource utilization based on admitting service and platelet-refractory status. One thousand nine hundred forty-four platelet units were transfused to 245 hospitalized patients (50.6% male, mean age 49 years) during the study period. The majority of platelet units transfused were single donor (N = 1,460, 75%) and administered to bone marrow patients and patients with a hematological malignancy/disorder. Median hospitalization costs per admission were $27,750, ranging from a high of $58,729 for admission to the Bone Marrow Transplant service to $13,856 per admission to the Internal Medicine/Other service. Patients were refractory to platelet transfusions during 21.6% of hospitalizations. Hospital stays were longer (35.0 days vs. 14.4 days, P < 0.001) and inpatient hospital costs ($103,956 vs. $37,817, P < 0.001) were more than two and a half times higher for patients refractory to platelet transfusions. Platelet utilization, resource use, and costs vary by admitting service. Refractoriness to platelet transfusion was associated with significantly greater costs and lengths of stay. Monitoring platelet transfusion practices, particularly for patients refractory to platelet transfusions, may be beneficial for limiting costs and improving efficacy.

Adult↗

Antibody-mediated inhibition of the human alloimmune response to platelet transfusion in Hu-PBL-SCID mice.

Severe combined immune deficient (SCID) mice were engrafted with human (Hu) peripheral blood lymphocytes (PBL) from a previously alloimmunized donor and transfused with HLA-mismatched platelets. We have previously shown this to be a useful model for platelet transfusion. These engrafted mice (Hu-PBL-SCID mice) produced high levels of alloantibody in response to standard platelet preparations. However, when the first platelet challenge was presensitized with anti-HLA antibody and then transfused there was a marked reduction in the amount of alloantibody produced to five subsequent untreated platelet transfusions. Platelets pretreated with platelet-specific anti-HPA-1a (PL(A1)) sera did not induce a decrease in the anti-HLA alloantibody response. This demonstrated that platelet-induced HLA alloimmunization can be blocked by anti-HLA antibody-sensitized cells.

Animals↗

Platelet transfusion support for patients with cancer and hematologic malignancies.

Advances in platelet transfusion have contributed to improved outcomes in the treatment of patients with cancer and leukemia. However, the optimal strategies to avoid some of the side effects that could result from platelet transfusions remain under investigation. These side effects include the development of refractoriness to transfusions, alloimmunization, transfusion reactions, the transmission of infectious agents, and transfusion-associated graft-versus-host disease. Leukodepletion by filtration is promising as a means of preventing the development of alloimmunization. Results of the Trial to Reduce Alloimmunization to Platelets will be reported shortly and will shed more light on that issue. Bedside filtration of cellular blood products also diminishes the transmission of cytomegalovirus infections by that route. Transfusion reactions are often mediated by cytokines in the plasma fraction of transfused platelet concentrates, and leukodepletion prior to storage reduces their incidence. Serious bacterial infections are sometimes transmitted by platelet transfusions and improved methods are needed for their detection and prevention. Photochemical methods that could inactivate bacteria and viruses in contaminated products deserve further study.

Hematologic Neoplasms↗

Prophylactic platelet transfusion threshold during therapy for adult acute myeloid leukemia: 10,000/microL versus 20,000/microL.

BACKGROUND AND OBJECTIVE: The threshold for prophylactic platelet transfusions has been classically established at 20,000/microL. In 48 patients with de novo acute myeloblastic leukemia (AML) we analyzed the effect of reducing the threshold for prophylactic platelet transfusion from 20,000/microL (group A) to 10,000/microL (group B) after induction and consolidation chemotherapy. DESIGN AND METHODS: Forty-eight adult patients with de novo AML diagnosed in a single institution in a nine year period were enrolled in the study. Between January 1989 and December 1993 the patients received prophylactic platelet transfusions when their platelet count was below 20,000/microL (group A), and from January 1994 to March 1998 prophylactic platelet transfusions were indicated below 10,000/microL or between 10,000/microL and 20,000/microL if there was any consumption factor. RESULTS: The mean number (SD) of platelet transfusions during induction was 8.4 (5.3) in group A and 8.5 (5.5) in group B; and during consolidation 4.7 (3.4) in group A and 4.6 (3.8) in group B (p = n.s.). Excluding the cases with consumption factors from the analysis, group B patients required 34% fewer transfusions during induction and 15.5% fewer during consolidation (p = 0.04). There were no differences between groups regarding major bleeding episodes. INTERPRETATION AND CONCLUSIONS: Our data show that the threshold for prophylactic platelet transfusion can be safely set at 10,000 microL during induction and consolidation chemotherapy for adult patients with de novo AML.

Acute Disease↗

Hypotensive reactions: a previously uncharacterized complication of platelet transfusion?

BACKGROUND: In 1993, the American Association of Blood Banks (AABB) received reports of severe hypotensive reactions associated with platelet transfusions. The question arose as to whether these reports were indicative of a previously uncharacterized platelet transfusion reaction. STUDY DESIGN AND METHODS: To further characterize these reactions, the AABB Transfusion Practices Committee developed a series of three questionnaires. The initial questionnaire was sent to all AABB institutional members; the two subsequent questionnaires were sent to those institutions reporting severe and/or unusual platelet transfusion reactions. This report focuses on the 24 responses to the third and most detailed questionnaire, which specifically addressed reactions that were characterized by hypotension and/or unexplained respiratory failure. RESULTS: Of the 24 detailed responses received, 4 were not considered to represent unusual reactions to platelet transfusion, 3 described reactions consistent with a (presumably unrecognized) diagnosis of transfusion-related acute lung injury, and 17 described reactions that were primarily characterized by hypotension. The majority of the hypotensive reactions occurred within 1 hour of the beginning of the transfusion (88%), were associated with respiratory distress (82%), and resolved rapidly after cessation of the transfusion (82%). Eighty-eight percent of implicated components had been white cell reduced by filtration. CONCLUSION: The hypotensive platelet transfusion reactions that were described appear to represent a previously uncharacterized complication of platelet transfusion. However, the nature of the questionnaires used in this investigation does not allow the drawing of firm conclusions as to the frequency or the cause of these reactions.

Adolescent↗

Platelet function testing to assess effectiveness of platelet transfusion therapy.

BACKGROUND: Posttransfusion corrected count increments (CCI) following administration of platelets is the standard method for assessing effectiveness of platelet transfusion therapy. However, improvement in platelet count following transfusion may not necessarily indicate improvement in platelet function or restoration of primary hemostatic capacity. To address this possibility, we investigated the effectiveness of platelet transfusion based on results of the Platelet Function Analyzer (PFA-100) and post-transfusion CCI. INVESTIGATION DESIGN AND METHODS: Platelet transfusion requests with different indications received at the blood bank were evaluated for inclusion in the investigation. Pre-transfusion, the following laboratory tests were performed: (1) PFA-100 assays (blood collected in 3.2% buffered sodium citrate) performed with CEPI and CADP test cartridges; (2) complete blood count (in EDTA) and platelet count; and (3) routine coagulation profile including PT, PTT, fibrinogen and D-Dimer. Only patients with normal coagulation profiles were included. The same set of tests were performed on a new blood sample collected 10-60 min post-transfusion. Chart review and clinical evaluation for response to platelet therapy were performed on each occasion of transfusion. RESULTS: Thirty-one patients, five of whom were transfused on more than one occasion were evaluated. Thirty-five transfusion incidents were included. Posttransfusion outcomes were divided into two groups--those that resulted in shortening (>40 s) or normalization of the closure time (Group A) and those that had no change or greater prolongation of the closure time (Group B) when compared to the pre-transfusion value. Seventeen and eighteen transfusion episodes were categorized as Groups A and B, respectively. In Group A with improved PFA testing, nine patients had bleeding as indication for transfusion and six of these had concomitant improvement in their clinical picture as confirmed by control of hemorrhage. In contrast in Group B with no improvement in PFA testing, seven patients had bleeding as indication for transfusion and none showed cessation of hemorrhagic symptoms. These findings were statistically significant (p=0.0114). Similar evaluation using the post-transfusion CCI showed no correlation to bleeding symptoms in these patients (p-=0.500). CONCLUSIONS: In this evaluation, platelet function testing using the PFA-100 provided a better indication of transfusion outcome than did the post-transfusion CCI. Using this approach, PFA-100 may be an effective aid for supporting platelet transfusion decisions and may further aid in improving management of the hospital blood bank platelet inventory.

Adult↗

Effect of HLA Bw4/Bw6 compatibility on platelet transfusion responses of refractory thrombocytopenic patients.

Platelet transfusions from donors matched for cross-reactive antigens have been shown to be effective in providing hemostasis in alloimmunized thrombocytopenic patients. A significant number of these transfusions, however, fail to provide posttransfusion platelet recoveries. We investigated incompatibility in the Bw4/bw6 system as a possible explanation for these failures. The Bw4/Bw6 system is a biallelic antigen system closely associated with HLA-B. HLA-B locus antigens that are cross-reactive frequently differ in their Bw4/Bw6 specificity. Posttransfusion platelet recoveries from 21 alloimmunized thrombocytopenic patients homozygous for Bw4 or Bw6 and transfused with both Bw4/Bw6 compatible and incompatible platelets were analyzed. The mean 1-hr posttransfusion recovery was 84% following Bw4/Bw6-compatible platelets versus 52% with Bw4/Bw6-incompatible platelets (p less than 0.02). Twenty-four hours following transfusion, mean recoveries were 44% and 24%, respectively, (p less than 0.01). A subgroup of 8 patients (38%) was identified who had markedly lower responses following Bw4/Bw6-incompatible transfusions as compared to Bw4/Bw6-compatible transfusions (mean recoveries: 1 hr--compatible 100%, incompatible 27%, p less than 0.001; 24 hr--compatible 45%, incompatible 7%, p less than 0.01). These data suggest that the Bw4/Bw6 antigen system has clinical significance for some patients requiring platelet transfusion therapy and, when appropriate, should be considered in the selection of donors.

Blood Transfusion↗

Prevalence of platelet transfusion reactions before and after implementation of leukocyte-depleted platelet concentrates by filtration.

To determine the impact of platelet leukodepletion by filtration on the overall prevalence of reported transfusion reactions associated with platelet concentrates, we audited platelet transfusion reactions after infusion of platelet concentrates reported at University Hospitals of Cleveland over 6 months before (interval 1, July 1, 1989 to December 31, 1989) and after (interval 2, July 1, 1990 to December 31, 1990) implementation of the Pall PL 50 filter on our adult Hematology-Oncology inpatient unit (Division 60). Thirty-two (1.7%) of 1,901 random, pooled platelet transfusion events resulted in blood bank transfusion reaction workups in interval 1, compared to 90 (5.3%) of 1,704 in interval 2 (p < 0.001). The Division 60 service accounted for more of our hospital-wide platelet reactions after implementation of the filter in interval 2 (84%) than before filtration in interval 1 (42%), p = 0.002. The prevalence of reaction workups for Division 60 was 0.6% for interval 1, compared to 4.3% for interval 2 (p < 0.001). No differences were found between interval 1 and interval 2 for the rate of discontinuation of platelet transfusion (36 vs. 32%, p = 0.14), rate of premedication for platelet transfusion (72 vs. 65%, p = 0.6), percentage of direct antiglobulin test-positive reactions (17 vs. 5.4%, p = 0.09), percentage showing icteric/hemolyzed serum (15 vs. 4.4%, p = 0.09), or reactions believed to be due to red blood cell incompatibility (8.8 vs. 1.1%, p = 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

ABO Blood-Group System↗