The RADAR repository: a resource for studies of infectious agents and their transmissibility by transfusion.

BACKGROUND: An ongoing issue in transfusion medicine is whether newly identified or emerging pathogens can be transmitted by transfusion. One method to study this question is through the use of a contemporary linked donor-recipient repository. STUDY DESIGN AND METHODS: The Retrovirus Epidemiology Donor Study Allogeneic Donor and Recipient (RADAR) repository was established between 2000 and 2003 by seven blood centers and eight collaborating hospitals. Specimens from consented donors were collected, components from their donations were routed to participating hospitals, and recipients of these units gave enrollment and follow-up specimens for long-term storage. The repository was designed to show that zero transmissions to enrolled recipients would indicate with 95 percent confidence that the transfusion transmission rate of an agent with prevalence of 0.05 to 1 percent was lower than 25 percent. RESULTS: The repository contains pre- and posttransfusion specimens from 3,575 cardiac, vascular, and orthopedic surgery patients, linked to 13,201 donation specimens. The mean number of RADAR donation exposures per recipient is 3.85. The distribution of components transfused is 77 percent red cells, 13 percent whole blood-derived platelet concentrates, and 10 percent fresh frozen plasma. A supplementary unlinked donation repository containing 99,906 specimens from 84,339 donors was also established and can be used to evaluate the prevalence of an agent and validate assay(s) performance before accessing the donor-recipient-linked repository. Recipient testing conducted during the establishment of RADAR revealed no transmissions of human immunodeficiency virus, hepatitis C virus, or human T-lymphotropic virus. CONCLUSIONS: RADAR is a contemporary donor-recipient repository that can be accessed to study the transfusion transmissibility of emerging agents.

Particulate matter phenomenon: adverse event data and the effect of leukofiltration.

BACKGROUND: In February 2002, a multiorganizational task force investigated blood center reports of unusual particulate matter (PM) visible in packed red blood cells (RBC). A cohort study assessed increase in adverse events (AEs) related to this phenomenon, as well as the effect of post-leukofiltration (LF) on PM. METHODS: Two blood centers assessed AEs in patients transfused with RBCs having visible PM (classified as normal by-products of RBC preparation), PM RBCs subsequently LF, or RBCs without visible PM, and the effect of LF on PM removal. RESULTS: There was no difference in AEs in patients transfused with PM RBCs with or without LF compared to patients transfused with RBCs without visible PM. Subsequently filtered PM RBCs had acceptable residual WBC counts and median platelet removal of 92%. CONCLUSION: Transfusion of RBCs with visible PM or RBCs subsequently LF does not appear to increase the risk of an AE. LF use on PM RBCs results in the PM removal without adversely affecting filter performance. The lack of evidence of an increase in AE reports does not mean that there is no effect, and there may be a baseline AE rate attributable to PM which has not been thoroughly researched.

Detection of Chlamydia pneumoniae antigenin PBMNCs of healthy blood donors.

BACKGROUND: Because it has been increasingly recognized that Chlamydia pneumoniae may be linked to some chronic inflammatory diseases, including atherosclerosis, detection of this pathogen in blood from patients may be valuable in the diagnosis of such diseases. However, the prevalence of chlamydia in the blood of healthy donors has not yet been extensively studied. STUDY DESIGN AND METHODS: The presence of C. pneumoniae in PBMNCs obtained from healthy persons who donated blood for blood transfusion was assessed by a PCR that was specific for the C. pneumoniae 16S rRNA gene and by the use of staining with FITC-conjugated chlamydia MoAb. RESULTS: Twenty-one (8.9%) of 237 blood samples tested showed the presence of C. pneumoniae DNA and antigen in the PBMNCs. There was no significant difference in the presence of chlamydia in blood according to sex or to age between 20 and 59 years of age. However, a possible seasonal variation in the presence of chlamydia in blood from healthy donors was suggested by the results obtained. CONCLUSION: A significant percentage of healthy donors carry C. pneumoniae, which may be a risk factor for some chronic diseases.

Ultraviolet and visible light spectrophotometric approach to blood typing: objective analysis by agglutination index.

BACKGROUND: A new blood typing technology based on ultraviolet (UV) and visible light spectroscopy (UV/visible spectroscopy) has been developed. Blood groups and types are determined by quantifying reproducible changes in the UV and visible light spectra of blood in the presence of agglutinating antibodies. STUDY DESIGN AND METHODS: Samples of red cells in the presence and absence of agglutinating antibodies were examined by UV/visible spectroscopy. Blood groups and types were determined by comparing the optical density spectra obtained between 665 and 1000 nm. These comparisons generate numbers (agglutination index) ranging from 0 to 100, with smaller numbers corresponding to lack of agglutination and larger numbers corresponding to agglutination. RESULTS: The optical density of agglutinated blood is dramatically different from that of unagglutinated blood. The agglutination index derived from the relative slopes of the spectra is an objective indicator of agglutination strength. An agglutination index greater than 17 consistently and accurately established blood group- and type-specific agglutination. CONCLUSION: The method accurately predicted A, B, and O blood groups, and D type in over 275 samples. Scattering theory-based calculations of relative volumes of red cells before and after agglutination show a direct correlation with the agglutination index and provide the theoretical basis of the analysis. This quantitative technique is reproducible and has the potential for automation.

Hypotensive reactions associated with platelet transfusions and angiotensin-converting enzyme inhibitors.

BACKGROUND AND OBJECTIVES: To determine the cause of hypotensive reactions associated with platelet transfusions in coronary artery bypass surgery patients. MATERIALS AND METHODS: Platelet transfusion reactions that occurred during a 3-month period were retrospectively reviewed. RESULTS: Eighteen transfusion reactions occurred in 16 patients. Sixteen of the reactions were hypotensive and occurred in 14 patients transfused with platelets through negatively charged bedside leukocyte reduction filters. All 14 patients had received angiotensin-converting enzyme (ACE) inhibitors prior to transfusion. CONCLUSION: Preliminary findings suggest a new type of transfusion reaction associated with the use of negatively charged leukocyte reduction filters during platelet transfusions to patients on ACE inhibitors.

Prevention of transfusion-associated cytomegalovirus infection. Practice parameter. American Society of Clinical Pathologists.

This practice guideline represents the opinions and recommendations of the author(s), the American Society of Clinical Pathologists (ASCP) Practice Parameters Committee and the ASCP Board of Directors regarding the appropriate strategies for each clinical condition or laboratory test discussed in this guideline. This guideline is designed primarily as an educational resource for physicians in the provision of quality medical services. Adherence to this guideline is completely voluntary and does not necessarily assure a successful medical treatment or result. This practice guideline should not be considered inclusive of all proper procedures and tests or exclusive of other procedures or tests that are reasonably directed to obtaining the same results. The physician should apply his or her own professional judgment to the unique clinical circumstances presented by the particular procedure or test. Physicians are encouraged to document the reasons for whatever procedure or test they use (whether or not in conformance with this guideline). Physicians should also take care to consider other medical and scientific advances that are available after the date of adoption of this guideline. This practice guideline was developed exclusively for the purposes set forth above and not for use in connection with matters involving reimbursement, credentialing, or utilization review.

Use of irradiated blood components: practice parameter.

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare but fatal potential complication of transfusions. It is mediated by immunocompetent donor lymphocytes that cannot be eliminated by the recipient. Patients at risk for developing TA-GVHD are those who have a profound deficiency in cell-mediated immunity or those who share histocompatibility antigens with the donor and do not recognize the donor cells as foreign. Irradiation of cellular blood components is currently the only acceptable method for prevention of TA-GVHD. This practice guideline identifies the patient population who should receive irradiated blood components and describes the technical aspects of blood component irradiation that may affect the safety of the final product.

Lewis phenotype in women with preterm labor and premature rupture of the membranes.

OBJECTIVE: The purpose of this study was to evaluate the possible association between Lewis phenotype status in pregnant women and preterm labor (PTL) or preterm rupture of the membranes (PROM). METHODS: Red blood cell (RBC) Lewis phenotype was determined in 113 pregnant women admitted for PTL or PROM and in 121 controls. The results were controlled for the influence of race on Lewis phenotype. RESULTS: Pregnancy was associated with a higher frequency in women with the a-b- phenotype. There was no association between RBC Lewis phenotype and the occurrence of PTL or PROM. CONCLUSIONS: A susceptibility to PTL or PROM is not due to a lack of Lewis antigen expression on the plasma membrane of the vaginal mucosa.

Infection after injury: association with blood transfusion.

This study was undertaken to evaluate the association between red blood cell transfusions and infections in an easily stratified, homogenous group of injured adults. All received their initial transfusions upon arrival to the emergency department. Over 5 years, 390 uncross-matched trauma patients received type "O" red blood cells (RBCs) during initial resuscitation. One hundred fifty-four (39%) died within 7 days because of injuries sustained: 236 (61%) survived at least 7 days. Of these 236, clear differences could be seen between those receiving 6 or fewer or 7 or more units of RBCs. When adjusted for age, sex, and severity of injury (Champion Trauma Score, Injury Severity Score, TRISS), the risk of infection was higher in those receiving 7 or more units of RBCs. Similarly, risk of infection was related to units of RBCs transfused in a dose-related fashion. Blood transfusions should be avoided, if possible. Arbitrary "trigger points" for transfusions should be abandoned.

Informed consent for blood transfusion.

At present, few institutions consider separate informed consent for blood transfusions; rather, the patient gives this consent as part of a more comprehensive statement. This should change in the era of increasing patient's rights. The physician has the moral duty to fully inform the patient of the risks and benefits involved in the planned therapy. A separate consent requires time and paperwork but if done properly, it benefits the patients by increasing their knowledge and autonomy in the transfusion process.

Leukocyte-poor blood components: issues and indications.

Leukocyte-poor blood components (LPBC) have now become part of the armamentarium of available transfusable blood components. Indications for the use of LPBC vary in accordance with the underlying clinical condition, as well as the intended objectives of the transfusion therapy. Technological advances have made it possible to prepare LPBC using rather simple procedures. However, any manipulation of blood components and the additional use of filters, washing, rinsing solutions, etc. inevitably result in additional costs to the patient, the health-care institution, or third-party payers. Requests for LPBC involve the preparation of RBC or platelets, leuko-depleted by at least one log. Transfusion of LPBC must be done in a logical fashion that meets the needs of the patient. Currently, LPBC is indicated for patients with a history of nonhemolytic febrile transfusion reactions to delay alloimmunization to HLA antigens and avoidance of cytomegalovirus (CMV) infection.

Impact of explicit questions about high-risk activities on donor attitudes and donor deferral patterns. Results in two community blood centers.

Concern about the ineffectiveness of indirect questioning of donors about participation in activities with a high-risk of exposure to human immunodeficiency virus (HIV) led our two community blood centers independently to begin direct and explicit questioning of donors about such activities. The impact of direct questioning was assessed via a donor attitude survey and by comparing the number of donors deferred for a positive response to a direct verbal question with the number previously deferred for a positive response to indirect questions. Our donor attitude survey indicated 90% donor approval of direct questioning, and analysis of donor deferral patterns indicated almost a five-fold increase in the number of donors deferred for participation in high-risk activities. Our experience documents the acceptability of direct questioning of donors and indicates that such questioning may well have a positive impact on blood safety.

Use of Rh positive blood in emergency situations.

The emergency blood needs of 449 patients were met by supplying 1,717 uncrossmatched units of either red blood cells (RBC) type specific Whole Blood or group O RBC. The RBC were all Rh positive, and 601 units were transfused to 262 untyped patients. None of the patients presented with anti-Rh antibodies. Only 20 patients who were Rh negative received group O Rh positive RBC, and most of these patients were male. There were no acute hemolytic reactions or sensitizations of young females. Group O Rh positive RBC is our first choice to support patients with trauma who cannot wait for type specific or crossmatched blood. Those who do survive the emergency conditions can be reverted to blood of their own type without problem. Acceptance of Rh positive emergency transfusions by physicians giving emergency care can prevent unbalanced shortages in a regional blood supply system.

Comparison of assays for anti-HBc in blood donors.

Testing for anti-HBc has been recommended for use as a paradoxical or surrogate marker of carriers of non-A, non-B hepatitis. Serial sampling on a pool of 35,600 donors was done and those donors found to be repeatedly reactive by EIA method were rested using RIA methodology. Of 1367 donors found to be repeatedly reactive by EIA method, only 984 were confirmed by RIA. Those found to be reactive by EIA only were allowed to donate blood again, with only three of them becoming positive by both EIA and RIA on subsequent donations. The majority of these donors (107 out of 151) reverted to EIA negative status. Therefore, the finding of a positive anti-HBc by EIA method that could not be repeated by RIA method is not an early reproducible sign of anti-HBc reactive status.

Infusion of packed erythrocytes: an in vitro study of hemolysis.

Blood infusion through standard 20- and 22-gauge spinal needles, with varying hematocrit and rates of 1-6 mL/minute, did not result in significant amounts of erythrocyte hemolysis.

Autologous transfusion: a community blood bank experience.

Interest in the use of autotransfusion has increased greatly, as can be ascertained by looking at usage patterns and literature citations when compared to recent past years. In this paper, we discuss different autotransfusion methods, as well as the clinical experience of a community blood bank over a 3 1/2-year period with predeposited autologous transfusions for elective surgical procedures. Blood collected in Adenine-Saline (AS-1) preservatives allows up to 42 days of storage in liquid state after donation. An average of 2.4 units per donor-patient were drawn, with almost two thirds of them being reinfused during or immediately after surgery. Even though the results of cost analysis and efficiency are far from optimal, autologous transfusion remains an effective albeit expensive alternative to homologous transfusion.