COMPARISON OF PADC NEUTRON DETECTORS FROM DIFFERENT SUPPLIERS.

The objective of this study was to compare poly-allyl diglycol carbonate (PADC) track detectors from different suppliers for linear energy transfer (LET) spectrometry and neutron dosimetry. PADCs are commonly used for passive personal neutron dosimetry, where a common approach is to couple the PADC with a plastic radiator to generate secondary charged particles. The neutron dose can be estimated using the track density or the average LET of the secondary particles. The characterisation of PADC in terms of LET spectrometric capability and neutron sensitivity was previously performed using PADC from Intercast S.r.l., Parma, Italy, but this company stopped the production. Since it is common experience that material from different suppliers can have different properties, it became necessary to perform a comparison of PADCs from different suppliers with the Intercast material. The study permits to compare the reading procedures used at Politecnico di Milano and at the Paul Scherrer Institute.

Evaluation of a personal and environmental dosemeter based on CR-39 track detectors in quasi-monoenergetic neutron fields.

In this paper, the evaluation of the dosimetric capability of a detector based on a CR-39 solid-state nuclear track detector coupled to a 1 cm thickness of PMMA radiator was made with the aim of understanding the applicability of this technique to personal and environmental neutron dosimetry. The dosemeter has been exposed to monoenergetic and quasi-monoenergetic neutron beams at PTB in Braunschweig, Germany and at Ithemba Laboratories, in Faure, South Africa, with peak energies ranging from 0.565 to 100 MeV. The results showed a response that is almost independent of the neutron energy in the whole energy range.

Use of IgM monoclonal reagents licensed for tube tests in column agglutination technology.

BACKGROUND: Red cell (RBC) phenotyping using column agglutination technology (CAT) is currently limited by the reagents formulated in the system. To overcome this limitation, it was investigated whether monoclonal IgM reagents licensed for use with tube tests produced valid results with CAT. STUDY DESIGN AND METHODS: Commercial CAT, does not contain antisera, was used to evaluate Procedures A (40 microL of reagent and 10 microL of 4% RBCs) and B (50 microL of reagent and 50 microL of 0.8% RBCs) with or without incubation at room temperature. In Study 1, reagents were tested to determine whether potentiators inhibit the passage of antigen-negative RBCs through the column. In Study 2, CAT sensitivity was measured by the use of potency titrations to define a procedure for each reagent that matched or exceeded that of the tube method. In Study 3, the specificity of each reagent was determined in parallel with the CAT and tube tests. Typing of 1644 samples was performed. RESULTS: Study 1: Free passage was obtained with all reagents. Study 2: Immediate-spin methods using CAT produced the same results as the tube method. Study 3: With 8048 comparisons made, discrepant results were found in 32 transfused patients and in 6 cord blood samples, mainly with Lewis reagents. With comparison of CAT and the standard tube method, complete agreement was obtained with Kell reagents, 99.9-percent agreement with Kidd reagents, and 98.9-percent and 99.4-percent agreement with Lewis reagents. CONCLUSION: Most examined reagents seem suitable for use with CAT.

Evaluation of a new automated instrument for pretransfusion testing.

BACKGROUND: A number of automated devices for pretransfusion testing have recently become available. This study evaluated a fully automated device based on column agglutination technology (AutoVue System, Ortho, Raritan, NJ). STUDY DESIGN AND METHODS: Some 6747 tests including forward and reverse ABO group, Rh type and phenotype, antibody screen, autocontrol, and crossmatch were performed on random samples from 1069 blood donors, 2063 patients, and 98 newborns and cord blood. Also tested were samples from 168 immunized patients and 53 donors expressing weak or variant A and D antigens. Test results and technician times required for their performance were compared with those obtained by standard methods (manual column agglutination technology, slide, semiautomatic handler). RESULTS: No erroneous conclusions were found in regard to the 5028 ABO group and Rh type or phenotype determinations carried out with the device. The device rejected 1.53 percent of tests for sample inadequacy. Of the remaining 18 tests with discrepant results found with the device and not confirmed with the standard methods, 6 gave such results because of mixed-field reactions, 10 gave negative results with A2 RBCs in reverse ABO grouping, and 2 gave very weak positive reactions in antibody screening and crossmatching. In the samples from immunized patients, the device missed one weak anti-K, whereas standard methods missed five weak antibodies. In addition, 48, 34, and 31 of the 53 weak or variant antigens were detected by the device, the slide method, and the semiautomated handler, respectively. Technician time with the standard methods was 1.6 to 7 times higher than that with the device. CONCLUSION: The technical performance of the device compared favorably with that of standard methods, with a number of advantages, including in particular the saving of technician time. Sample inadequacy was the most common cause of discrepancy, which suggests that standardization of sample collection can further improve the performance of the device.

Implementation of a quality system (ISO 9000 series) for placental blood banking.

Although placental blood has recently become a new source of hematopoietic progenitors for marrow replacement, limited attention has been given to systems suitable to ensure the short-term and long-term quality of placental blood units used for transplantation. In this article, we describe a quality system for placental blood banking developed in accord with ISO 9002 norms at Milano Cord Blood Bank. The quality system is the organizational structure, procedures, processes, and resources needed to implement quality management. ISO 9002 is a model for quality assurance in production, installation, and servicing, which includes a number of clauses providing guidance for the implementation of the quality system. The quality system was started by the bank medical director with step 1: the general quality plan, which included (a) the written description of mission, objectives, technical and organizational policies, and staff organization chart of the placental blood bank, (b) the definition and acquisition of adequate financial, human, and structural resources, (c) the appointment of a quality system head independent from the production laboratory and reporting directly to the medical director. Tasks of the quality system head were (a) to identify the placental blood banking process together with the placental blood bank personnel, (b) to implement a documentation plan finalized at the production and maintenance of (i) the quality manual, which provides a summary on how the bank operates with a quality system in compliance with the ISO 9002 clauses, (ii) the general procedures (or quality system procedures), which provide more detail on selected clauses, including at least those prescribed by the ISO 9002 standard, (iii) the operative procedures (or process procedures), which describe in detail the process of placental blood banking and how technical activities must be performed, (iv) the work instructions, which provide stepwise descriptions of individual activities, (v) records/forms for data collection and storage, (c) to identify quality indicators, (d) to start a regular internal audit, (e) to report audit results to the medical director for review. This was followed by step 2: the job descriptions, staff training, and qualification; step 3: the documentation plan; step 4: the internal audit plan; step 5: the launch of the quality system, and step 6: the assessment by an external team from an accredited third-party organization and final certification for compliance to ISO 9002. The quality system, which must be maintained and undergo external audit at regular intervals so that certification is confirmed, ensures the high probability that placental blood units provided to clinicians conform regularly to predefined levels of quality.

Use of SERVQUAL to assess clinicians' satisfaction with the blood transfusion service.

BACKGROUND AND OBJECTIVES: Limited information is available on the level of satisfaction of clinicians with services delivered by blood banks. The purpose of this study was to evaluate the satisfaction of clinicians with our blood transfusion service. MATERIALS AND METHODS: We prepared a questionnaire based on SERVQUAL, a method used to measure customers' appreciation of quality of service, by assessing the gap between perceived and expected quality. The questionnaire consisted of 14 items grouped according to five dimensions of quality of service: assurance, empathy, responsiveness, reliability, tangibles. Clinicians were asked to give two scores on a scale from 1 to 7 for each item, score (e) representing what they expected from an 'excellent' service, score (r) how they graded the service received. We considered wide differences in scores of service expectation and receipt for a question to be indicative of either service above expected levels (r > e) or service below expectation (r < e); similar scores for both expected and received service (within 1 point on the grading scale) were taken to indicate that the service received was that which was expected. RESULTS: A total of 184 questionnaires (49%) were returned. For the 14 items considered, the proportion of clinicians expressing levels of satisfaction similar to or above expectation ranged from 67 to 96%. Three critical areas, which clinicians considered important (expectation scores 6-7) were associated with satisfaction below expectation in more than 20% of responders. They were: clarity of procedures, clarity of blood request forms, and convenience of blood request and issuing times, which were rated as important by 77, 80 and 72% of clinicians, respectively. CONCLUSION: SERVQUAL was useful to gather information on the level of clinicians' satisfaction with our transfusion service.

Quality control of red cell filtration at the patient's bedside.

BACKGROUND: Concern has been raised about the quality of white cell (WBC) reduction in blood components when it is performed by filtration at the patient's bedside. Thus, the quality of red cell (RBC) filtration performed at the bedside through two new flatbed WBC-reduction filters was evaluated. STUDY DESIGN AND METHODS: In the laboratory, 25 and 10 RBC units suspended in additive solution were stored for 1 to 2 and 14 to 21 days, respectively, and filtered through each filter. At the end of filtration, an automated complete blood count and a manual WBC count (Nageotte chamber) were determined in two samples collected from 1) a segment clamped at 5 and 25 cm below the filter along the line connecting prefiltration and postfiltration bags and 2) the postfiltration bag. In addition, 10 of the 11 nurses of the hematology outpatient clinic administered to hematologic patients 25 RBC units stored for 1 to 2 days through each type of filter. At the end of transfusion, a segment was collected from the transfusion set and a WBC count was performed as described above. No filter priming or rinsing with saline was done. RESULTS: WBC counts obtained after laboratory filtration in the segments were similar to those obtained from the postfiltration bags and from the segments collected at the bedside in all cases, with the exception of 14- to 21-day-old RBCs filtered in the laboratory through one of the filters, which produced slightly higher WBC counts in the segments than were seen in the postfiltration bags. The difference was not significant. In no case was the count in the postfiltration bag higher than that in the segment. Nurse training was easy, and bedside filtration was associated with no untoward effects. CONCLUSION: The RBC filtration at the patient's bedside can be equal in quality to that performed in the laboratory, at least in such clinical settings as hematology and oncology departments in which blood transfusion is common practice, and if simple training is provided to the nursing staff. Under the conditions of this study, it seems that quality control of RBC bedside filtration is feasible and simple.

White cell-reduced red cells prepared by filtration: a critical evaluation of current filters and methods for counting residual white cells.

White cell (WBC) reduction, red cell (RBC) recovery, and filtration time were determined in 1-day-old standard and buffy coat-depleted RBCs filtered in the laboratory through six commercial filters for WBC reduction. Residual WBCs were counted with a Bürker chamber (BC), with a Nageotte chamber (NC), and by flow cytometry (FC). Results show that BC counts were 0 in several cases in which WBCs were detected with NC and FC, which indicated that the traditional BC method is too insensitive in use with currently available filters. Calibration curves performed by FC and with NC with samples containing known concentrations of WBCs from 1000 to 1 per microL showed that both FC and NC detected, on average, 67 percent of WBCs present in the samples (efficiency). However, the efficiency of FC showed small variability (61-70%) at different WBC levels, whereas the variability with NC was large (39-91%). This greater variability prevented the correction of NC counts by using a single factor and indicated difficulty in NC standardization. Therefore, because our main aim was to compare different filters rather than to define absolute levels of WBC contamination, uncorrected FC and NC counts were chosen to be reported. True WBC counts per unit should not exceed values that can be obtained by dividing uncorrected counts by the lowest efficiencies (61% for FC and 39% for NC). Uncorrected NC and FC counts were below 2 x 10(6) per unit in all units processed through three of the filters and below 5 x 10(6) per unit in all units processed through the other three.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective evaluation of posttransfusion hepatitis.

The incidence of posttransfusion hepatitis (PTH) was determined prospectively at our institution. An active surveillance program of transfused surgical patients was set up; alanine aminotransferase (ALT) levels were determined before transfusion and at monthly intervals for 6 months after transfusion. Patients with confirmed ALT values greater than 2.5 times the upper reference values were referred to the out-patient clinics for diagnosis. Of 4051 surgical patients who underwent transfusion between January 1986 and December 1989, 2459 (60.7%) were enrolled in the surveillance program, and 1018 (25.1%) completed the follow-up; 238 patients received autologous blood only and were used as controls. No PTH was observed in the control patients, and the incidence of the disease in patients receiving homologous blood was 10.97 percent in 1986, 6.58 percent in 1987, 5.55 percent in 1988, and 4.29 percent in 1989; the decreasing trend is significant (p = 0.018).

Removal of white cells from red cells by transfusion through a new filter.

The effectiveness of a new filter (RC100) for the preparation of white cell-depleted red cells (RBCs) at the bedside was evaluated in vitro and in vivo using three RBC products: standard RBC concentrate (CPDA units), RBCs suspended in saline-adenine-glucose-mannitol additive solution after the removal of plasma (SAGM units), and RBCs suspended in SAGM after the removal of plasma and buffy coat (SAGM-BC units). Median RBC recovery was at least 92 percent when 2 units were administered through one filter; median values for residual white cells and platelets were less than or equal to 20 x 10(6) and less than or equal to 2.5 x 10(9) per 2 units, respectively. The in vivo study was carried out in 80 multiply transfused patients with thalassemia, 35 of whom had experienced frequent nonhemolytic transfusion reactions when given standard or buffy coat-free RBCs. During the 6-month study, each patient was given two transfusions of each type of RBC product One febrile nonhemolytic transfusion reaction occurred in each of two patients receiving SAGM-BC units, but in no other case. If the flow rate is not reduced, the median transfusion time is 35 minutes per CPDA unit and 15 minutes per SAGM and SAGM-BC unit. It is concluded that the transfusion of RBCs through the RC100 is a simple and effective procedure to administer white cell-depleted RBCs prepared at the bedside.

Prevalence of hepatitis C virus antibodies in Italian blood donors. The Italian Cooperative Group.

11,117 blood donors from 24 blood transfusion services evenly distributed throughout the various Italian regions were tested for the presence of hepatitis C virus (HCV) antibodies in the serum and serum alanine aminotransferase (ALT) level. The results are as follows: (1) anti-HCV seroprevalence in Italy was 0.87% with a difference between Northern and Southern regions (0.68 vs. 1.37%) and between younger and older subjects (0.62 vs. 1.21%); (2) prevalence of elevated ALT levels was 4.74% without a North-South effect (except than for markedly elevated ALT levels); (3) anti-HCV seroprevalence was higher in subjects with elevated ALT (5.0%), with a North-South effect (2.2 vs. 9.9%) and particularly high (19.2%) in subjects with markedly elevated ALT; (4) ALT levels were elevated in 26.2% of anti-HCV positive subjects, with a North-South effect (14 vs. 40.5%).

Quality assessment of transfusion practice in elective surgery.

A program of quality assurance (QA) was adopted to improve blood transfusion practice in elective surgery at a large urban hospital. For this purpose, a cooperative multidisciplinary group was formed, key indicators were identified, and an organization was set up. Data collected by this organization in the 1-year period needed for implementation of the program indicated that blood misuse was common practice. In fact, overrequest, overtransfusion, excessive reconstitution of whole blood (i.e., concurrent transfusion of red cells and fresh-frozen plasma), and underuse of predeposit were found in all ten surgical departments of the hospital. In a pilot study, data were collected from one surgical department during and after the implementation phase of the QA program; comparison of these data showed a postimplementation reduction of about two thirds in overtransfusion, whereas overrequest, reconstitution of whole blood, and predeposit rates remained unchanged. These results prompted continuation of the program in order to reach a definitive evaluation of its effectiveness.

Leukocyte depletion of red cell units at the bedside by transfusion through a new filter.

Standard packed red cell (PRC) units can be depleted of leukocytes and platelets if they are transfused through a blood administration set in which the usual 170-mu filter has been replaced by a leukocyte removal filter (Sepacell R-500). During a 6-month period, 1550 PRC units were transfused through this filter in 611 transfusions to 80 multitransfused patients with thalassemia who had had a patient reaction rate (PRR) of 63 percent and a transfusion reaction rate (TRR) of 13 percent when given standard PRC or buffy-coat-depleted PRC. When given filtered PRC, PRR and TRR became 3.7 percent and 0.5 percent, respectively. The effectiveness of the filter was also evaluated in vitro. By filtering 2 standard PRC units through the same filter, median values (and ranges) for red cell recovery and for residual leukocytes and platelets were 87 percent (83-92), 6.1 X 10(6) (0-100), and 2.7 X 10(9) (0.6-9.7), respectively. Although refinements are needed to improve standardization of the filter and to increase red cell recovery (which is low when 1 unit is filtered through one filter) and blood administration rate, the ability to provide leukocyte-free red cells prepared at the bedside for virtually all recipients appears to be a realistic goal.

The clinical importance of leukocyte depletion in regular erythrocyte transfusions.

Antilymphocyte, antigranulocyte and antiplatelet alloantibodies, T lymphocyte subsets, expression of HLA-DR antigens on T lymphocytes and NK cell function were determined in 11 homozygous beta-thalassemic children multitransfused ab initio with Erypur-filtered leukocyte-free red cell units (group A) and in 13 similar children multitransfused with standard packed red cell units (group B). No antibodies were found in group A patients, whereas 69% of group B patients were immunized. The two groups did not differ significantly with regard to the other test results. Considered together, thalassemia patients showed a percentage of T4+ cells and a NK cell function that were significantly lower than those found in a reference group of 16 healthy male blood donors. Thalassemics moreover showed a higher than normal percentage of T3+, T4+ and T8+ cells expressing HLA-DR antigens. The results indicate that leukocyte-free red cells should be the treatment of choice for prospective recipients of multiple transfusions, since they are capable of preventing (or delaying) the production of alloantibodies against leukocytes and platelets. From the data of the present study, it does not seem that the transfusion of leukocyte-free red cells is capable of preventing the abnormalities of some immunological tests that occur in some multitransfused patients. Further investigations, however, are needed to draw conclusions on this problem.

The manual preparation of leukocyte-poor red cells for transfusion by a new filter.

Standard and buffy-coat-depleted red cell concentrates were filtered through a new cellulose acetate filter with a manual procedure. No residual leukocytes could be detected in 19 of the 21 filtered units. Extracellular hemoglobin after red cell filtration and concentration never exceeded 10 mg per unit. No transfusion reaction occurred in 10 recipients with potent lymphocytotoxic antibodies in their serum and histories of febrile transfusion reactions. This filter allows the preparation of leukocyte-poor red cell units with a safe, simple, and effective manual procedure.