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Background: Septic platelet transfusion reactions (SPTRs) are the most common, serious risk of transfusion. Because SPTRs result from donor skin flora or asymptomatic bacteremia, the use of single-donor platelets (SDPs) has been proposed to reduce the risk of SPTRs from the risks with pools of platelet concentrates (PCs).Study Design and Methods: Beginning in 1986, all febrile transfusion reactions were evaluated by culture of the platelet bag. Confirmed SPTRs were identified by isolation of the same bacteria from the bag and the patient's blood or by positive Gram's stain of the bag that confirmed a positive platelet culture. In 1987, a program to minimize PC use in favor of SDP use was initiated as a means of reducing SPTRs.Results: In 12 years, the use of SDPs increased from 51.7 percent to 99.4 percent of all platelet transfusions at one institution. SPTRs fell from three events in 1 year to the current rate of one event per year. The incidence of SPTRs decreased from 1 in 4,818 transfusions to 1 in 15,098 transfusions. The rate of SPTRs due to PCs was 5.39 times higher than that of SPTRs due to SDPs (95% CI, 1.89,12.9).Conclusion: The use of SDPs is a simple means of reducing SPTRs. Other measures such as sterilization will be required to eliminate all SPTRs. [ABSTRACT FROM AUTHOR]

Classical crop models have been developed to predict crop yield and quality, and they are based on physiological and environmental inputs. After molecular discoveries, models should integrate genetic variation to allow predictions that are more genotype-dependent. An interesting approach, Quantitative Trait Locus (QTL)-based ecophysiological modeling, has shown promising results for the design of ideotypes that are adapted to biotic and abiotic stresses, but there are still limitations to attaining a fully integrated model. The aim of this case study is to clarify the impact of choosing different model equations (closely related and with different numbers of parameters) and optimization methods on the detection of QTLs controlling the parameters of crop growth. Different growth equations were parameterized based on a genetic population by following different approaches. The correlations between parameters were analyzed, and two different strategies were adopted to address the correlation issue. QTL analysis was performed on the optimized values of the parameters of the growth equations and on the observed dry mass (DM) data to validate the QTLs detected. Overall, models and strategies resulted in different QTLs being detected. Similar LOD profiles but with peaks of different heights were observed, some of which were significant, resulting in different numbers of QTLs. In some cases, peaks had slightly different positions or were absent. Even closely related growth models led to the detection of different QTLs. The goodness of fit and complexity of the growth models were found to be insufficient to select the best model. Calculating parameters independently of observed data may not be a good strategy, whereas setting parameters independent of the genotype is recommended. Given the large-scale global optimization problem and the strong correlations between parameters, the two algorithms tested showed poor performance. Currently, the lack of effective algorithms is the main obstacle to answering the question posed. The authors therefore suggest testing different model formulations and comparing the QTLs detected before choosing the best formulation to use in an ecophysiological modeling approach based on QTLs., Competing Interests: The authors have declared that no competing interests exist.

A recently introduced system for antibody detection (ReACT) consists of affinity columns (AFC) that contain protein A and protein G-coated agarose. We compared the ReACT system to a conventional tube low-ionic-strength saline antiglobulin test (LISS-AGT). We selected 100 LISS-AGT positive samples with clinically important and benign antibodies of varying strengths and 130 LISS-AGT negative samples to evaluate by the AFC method. AFC tests were positive with all 84 clinically important antibodies, including 36 antibodies that reacted <= 1+ at LISS-AGT (0% falsely negative). Eleven of 16 (69%) clinically benign antibodies reacted by AFC. Five samples (2 anti-Sda, 2 anti-I, and 1 inconclusive) were negative by AFC. AFC tests were negative with all 130 samples that were negative by LISS-AGT (0% falsely positive). The AFC method showed results comparable with results obtained with a conventional tube LISS-AGT for detection of clinically important antibodies. Some unwanted, clinically benign antibodies may not be detected by the AFC method.

We evaluated the performance of the Inverness Blood Grouping System (IBG Systems, Inc., Laytonsville, MD) for the ABO and D red cell grouping of patients' samples. The IBG System is a semiautomated microplate device for blood grouping and antibody detection We tested 2,051 samples using the IBG System and by manual grouping techniques. In no instance did the IBG System give a final ABO interpretation different from the final manual technique. For three samples, the JBG System's ABO interpretation was different from the manual interpretation. An error in interpretation by the technologist performing the manual testing was responsible for the discrepancies. The IBG System identified one sample as D-positive that was grouped as D-negative by manual testing. The patient's sample had been previously grouped manually as a weak D. Au other D results were in agreement. The IBG System provided ABO interpretatinns without technologist's intervention on 1,765 (86.1%) of the samples. In 153 (7.5%) of the samples, a single, equivocal reaction required visual inspection, but no repeat testing was necessary. In 133 (6.5%) of the samples, either repeat testing or reliance on only the manual results was required for final ABO group interpretation. The IBG System is a reliable and efficient alternative to manual techniques for ABO and D grouping of patients' samples.

Neonatal blood component transfusion practices during 1989 were surveyed via a questionnaire developed by the Pediatric Hemotherapy Committee of the American Association of Blood Banks. Of 1790 questionnaires mailed, 452 were selected to form the database for this analysis because they were from institutions in which neonates were transfused. Nearly all institutions contained intensive care units directed by neonatologists and were involved in the management of high-risk infants. Results from institutions serving as the primary pediatric teaching hospital of a medical school were compared with those with no medical school affiliation. Thirty-six percent of primary pediatric teaching hospitals and 52% of hospitals with no medical school affiliation performed pretransfusion testing in excess of that required, resulting in additional blood loss in neonates. Sixty-six percent of primary pediatric teaching hospitals used fresh frozen plasma to adjust the hematocrit of red blood cell concentrates prior to transfusion (a practice increasing donor exposure), compared with only 29% of hospitals with no medical school affiliation. The usual indication for small-volume red blood cell transfusions in severely ill neonates was to maintain a desired hematocrit level, whereas for stable infants, red blood cell transfusions were given to treat symptomatic anemia, rather than to maintain a predetermined hematocrit. As found in 1985, neonatal transfusion practices in 1989 were variable. However, improvements have occurred since 1985 to suggest that further research and educational efforts may serve to promote even better neonatal transfusion therapy.

Neonatal transfusion practices during 1989 of 452 institutions involved in transfusing infants were surveyed by questionnaire. Most respondents (77%) transfused fresh frozen plasma appropriately (ie, primarily to treat coagulation disorders). However, 11% stated that their most frequent use of fresh frozen plasma was solely to treat hypovolemia, a practice generally not recommended. Seventy-eight percent of respondents transfused platelets to treat bleeding infants with blood platelet counts of less than 50 x 10(9)/L; 84% gave platelets to sick, premature neonates with counts of less than 50 x 10(9)/L whether or not bleeding was evident. Only 35% of respondents transfused granulocytes for neonatal sepsis; most institutions used buffy coats isolated from units of blood--a product readily available, but of questionable efficacy when compared with leukapheresis granulocytes. Ninety-three percent of respondents provided blood components with low risk of transmitting cytomegalovirus: components from seronegative donors were used by 84%, leukocyte-reduced products by 6%, and a combination by 10%. Thirteen percent of respondents gave gamma-irradiated blood components to all and 46% gave them to some neonates to prevent graft vs host disease. Forty-one percent did not routinely irradiate. Ten percent of respondents used leukocyte reduction instead of gamma irradiation to prevent graft vs host disease, a practice currently not advocated. Thus, national transfusion practices for neonates are variable, controversial, and, occasionally, other than those usually recommended. Additional research and educational efforts are needed to ensure optimal transfusion therapy.

Hemolytic transfusion reactions typically are explained by red cell serologic incompatibilities. We describe a patient in whom a clinically significant red cell alloantibody could not be demonstrated, despite the occurrence of several clinically severe hemolytic reactions. Serologic studies using multiple techniques demonstrated only an anti-Bga; these studies included standard procedures as well as more sensitive experimental techniques. A 51Cr survival study using red cells from a random unit, compatible in vitro with conventional techniques, showed 72 percent survival at 1 hour and 7 percent survival at 24 hours. R2R2 (hr" (e) negative) red cells in a second 51Cr survival study showed 90 percent survival at 1 hour and 92 percent survival at 6 hours. The patient was transfused with R2R2 units which were tolerated well and survived normally. Extensive serologic testing still demonstrated only an anti-Bga. A third 51Cr survival study, 10 months after the first study, with an R1R1 (hr" (e) positive) sample showed 90 percent survival at 1 hour and 42 percent survival at 6 hours. A fourth study using a larger aliquot of R2R2 (hr"(e)negative) 51Cr-labeled red cells, examined over 2 weeks showed a near normal 21-day survival of 50 percent. These 51Cr survival studies, along with normal survival of hr" (e) negative units, suggest that this patient destroys hr" (e) positive red cells despite negative serologic testing.

The development and implementation of a preventive maintenance program are described. The details of the program are discussed to demonstrate its initial planning and the subsequent stages as a process that would be applicable to any medical laboratory.

The long-term survival of serologically incompatible red cell units was measured in five patients with antibodies to high-frequency antigens. Initially, the survival of 1 ml of 51Cr-labeled incompatible red cells was measured over 1 hour. After demonstrating that the 1-hour survival times were successful (greater than 70%), each patient then received 5 ml of the same 51Cr-labeled red cells followed by the transfusion of the remainder of the red cell unit. The long-term T 1/2Cr survival for each case was patient 1 (anti-McCa), 15 days; patient 2 (anti-JMH), 12 days; patient 3 (anti-Kna), 31 days; patient 4 (anti-McCa), 12 days; and patient 5 (anti-Hya), 14 days. Each antibody tested in an in vitro homologous macrophage assay showed less than 5 percent phagocytosis. Anti-JMH was the only antibody to react with IgG subclass antisera and was determined to be IgG4. The macrophage assay, IgG subclass testing, and short-term (1 hour, 1 ml) 51Cr survival studies all indicated that the short-term survival was good. However, only the measurement of long-term survival with transfused units of serologically incompatible red cells was able to determine the actual survival, and "clinical significance" of the alloantibodies. Determining the actual long-term survival by the method described here can be of importance for patients requiring chronic red cell transfusion.

A case of Tn polyagglutinability in a patient with acute myelomonocytic leukemia is described. This represents the third report in which Tn polyagglutination has been associated with a leukemic state. Serologic recognition of Tn polyagglutination and probable causes are discussed. Known cases of Tn-polyagglutinability are reviewed.

A type-and-screen procedure was established whereby obstetric patients with no complications would be tested for ABO, Rh, and unexpected antibody. If the antibody screen was negative, cross matches would not be performed. Type and screen could be converted in 20 minutes to cross match, or type-specific blood would be immediately available. Our initial results with type and screen demonstrated 65.5% utilization but 399 cross matches were done for 17 transfusions (cross match/transfusion ratio of 17.6/1). The protocol was changed so that all nonbleeding patients would be typed and screened. A total of 503 of the next 563 patients (89.3%) were typed and screened; cross matches provided 33 transfusions (cross match/transfusion ratio of 4.9/1). An estimated 964 cross matches were eliminated with cost savings of $14,460 in 3 months. We concluded that the type-and-screen procedure is an effective tool in reducing the cross match/transfusion ratio and in lowering costs in obstetric patients with no compromise in patient care, even in high-risk patients.

The use of type and screen (T&S) has reduced our overall crossmatch:transfusion (C:T) ratio from 2.5:1 prior to T&S to 1.9:1. Review of our progress, however, demonstrated only a partial reduction of C:T for elective cholecystectomy from 103:1 to 18:1, with only 39% T&S utilization. In addition, units crossmatched in excess of the surgical schedule for 174 high-risk patients had a C:T ratio of 18.6:1. Routine questioning of all excess orders proved unacceptable to blood bank staff and surgeons. An inflexible schedule was also deemed unacceptable. We therefore began monthly written summary reports to each surgical division listing each case in which extra crossmatching was reported and whether the units requested were transfused. These reports enabled the surgical directors to help monitor crossmatch utilization. In addition, we have reduced our C:T ratio of extra units for 405 high-risk patients to 4.0:1. T&S utilization for elective cholecystectomy has increased to 64%, and C:T has fallen to 9:1. These results demonstrate that establishing T&S can reduce the C:T ratio and patient costs; but continued attention is required to maximize the benefits of this procedure.