Blood Banking Practices Research Articles

Red Cell Antigens and the Practice of Transfusion Medicine in Nigeria - A review

OBJECTIVE: To generate data and information that would assist in the implementation of the recently enacted National blood transfusion policy METHOD: In the Worlledge series which was carried on amongst 31050 blood donors in Ibadan and other cities in the mid 1960s and 1970s, the following blood group systems were studies: ABO, Rhesus and MNSs. The other systems analysed include Kell, Duffy, Lutheran and P1. RESULTS: Amongst the 16 ethnic groups studied, the findings for the ABO systems shows that blood group O was the most common with a value ranging from 45.9 – 64.5% and an average of 53.5%, the highest and lowest contributions coming from the Ijaws (Ogonis) and Fulanis respectively. The next common was blood group A with a range of 12-30% and an average of 21.9% and the highest contribution of 30% was from the Efiks and the lowest value of 12% emanated from the Nupes. Blood group B is next with a value ranging from 11.9-30% with an average value of 21.5%, the highest contributors being the Busus (Katsina State) 30% and the lowest value of 11.9% was from the Ijaws (Ogonis). The least common blood group is AB with a value ranging from 0-4.9% with an average of 2.98%; the highest contribution of 4.9% coming from the the Fulanis while the Efiks recorded the lowest value CONCLUSION: In conclusion, red cell antigens obviously occupy a pivotal position in transfusion medicine in Nigeria. We recommend that further intensive research in this very important field be encouraged as this would not only provide the much needed epidemiological data but also help in uplifting blood bank practice in this environment as well as helping to ensure the effective implementation of the National blood transfusion policy. Nig Jnl Orthopaedics & Trauma Vol.2(2) 2003: 68-77

Inverted spin method for removing RBCs from BM buffy coat products.

Inverted spin is a method of removing RBCs that historically has been part of blood banking practice. We investigated the feasibility of using this method for RBC depletion of BM buffy coat products in situations where recipient RBC Abs have been identified to donor RBC Ags. The BM buffy coat product was placed in a transfer pack, inverted, centrifuged at 600 g for 10 min, suspended and the RBCs removed slowly into another transfer pack. Nine patients treated between April 1998 and February 2001 received products prepared by our version of the inverted spin procedure. We removed a median value of 81.2% of the RBCs, while still recovering a median of 94.3% of the mononuclear cells (median: 0.35 x 10(8)/kg; range: 0.17-0.9 x 10(8)/kg). The median volume of RBCs remaining in the product was 15.0 mL (range: 7.3-21.9 mL). The CD34(+) cell dose of the final product ranged from 1.0 x 10(6)/kg to 4.8 x 10(6) cells/kg (median: 1.9 x 10 6/kg). Granulocyte recovery (defined as ANC count >or=500/microL for a period of 3 consecutive days) ranged from 18-30 days post-infusion of the allograft (median: 24.0 days). One patient died shortly after his transplant from complications of his disease. No patient had any evidence of an acute hemolytic reaction. Advantages of the inverted spin method include no need for additives (e.g. hydroxyethyl starch, HSA, or O negative RBC), and use of equipment readily available in most processing laboratories.

Operating room blood delivery turnaround time: a College of American Pathologists Q-Probe Study of 12647 units of blood components in 466 institutions.

To determine the normative distribution of time elapsed for blood bank personnel to fill nonscheduled operating room (OR) blood component orders in hospital communities throughout the United States, and to examine hospital blood bank practices associated with faster blood component delivery times. Participants in the College of American Pathologists Q-Probes laboratory quality improvement program collected data prospectively on the times elapsed for blood bank personnel to fill nonscheduled emergent orders from hospital ORs for red blood cell (RBC) products, fresh frozen plasma (FFP), and platelets (PLTs). Participants also completed questionnaires describing their hospitals' and blood banks' laboratory and transfusion practices. Four hundred sixty-six public and private institutions located in 48 states in the United States (n = 444), Canada (n = 9), Australia (n = 8), the United Kingdom (n = 4), and Spain (n = 1). The median time elapsed between requests for blood components by OR personnel and the retrieval of those components by blood component transport personnel, and the median time elapsed between requests for blood components by OR personnel and the arrival of those components in ORs. Participants submitted data on 12 647 units of RBCs, FFP, and PLTs. The median aggregate request-to-retrieval turnaround times (TATs) for RBCs, FFP, and PLTs ranged from 30 to 35 minutes, and the median aggregate request-to-arrival TATs for RBCs, FFP, and PLTs ranged from 33 to 39 minutes. Most of the TAT was consumed by events occurring prior to, rather than after release of components from blood banks. Shorter prerelease TATs were associated with having surgical schedules that listed patients' names and procedures available to blood bank personnel prior to surgeries, and having adequate clotted specimens in the blood bank and completed type-and-screen procedures performed before requests for blood components were submitted to blood banks. Among the fastest-performing 10% of participants (90th percentile and above), request-to-retrieval TATs ranged from 12 to 24 minutes for the 3 blood components, whereas among the slowest-performing 10% of participants (10th percentile and below), request-to-retrieval TATs ranged from 63 to 115 minutes for the 3 components. Median TATs ranged from 33 to 37 minutes for the 3 components. Institutions with TATs in the fastest-performing 25th percentile more frequently stored cross-matched RBCs in the OR daily, stocked PLTs for unexpected surgical use, stored PLTs in or near the OR, and had laboratory rather than nonlaboratory personnel deliver components to the OR than did those institutions with TATs in the slowest-performing 25th percentile. Hospital blood bank personnel can deliver blood components to the OR in slightly longer than 30 minutes, measured from the time that those units are requested by OR personnel. Practices aimed at saving time before components are released from blood banks will be more efficient in reducing overall TAT than those practices aimed at saving time after components are released from blood banks. Specific practices associated with shorter blood delivery TATs included providing blood bank personnel with access to the names of surgical patients potentially requiring blood components, having pretransfusion testing completed on those patients prior to surgery, having ample blood products on hand, and having laboratory personnel control blood product delivery.

Operating room blood delivery turnaround time: a College of American Pathologists Q-Probe Study of 12647 units of blood components in 466 institutions.

Objectives To determine the normative distribution of time elapsed for blood bank personnel to fill nonscheduled operating room (OR) blood component orders in hospital communities throughout the United States, and to examine hospital blood bank practices associated with faster blood component delivery times. Design Participants in the College of American Pathologists Q-Probes laboratory quality improvement program collected data prospectively on the times elapsed for blood bank personnel to fill nonscheduled emergent orders from hospital ORs for red blood cell (RBC) products, fresh frozen plasma (FFP), and platelets (PLTs). Participants also completed questionnaires describing their hospitals' and blood banks' laboratory and transfusion practices. Setting and participants Four hundred sixty-six public and private institutions located in 48 states in the United States (n = 444), Canada (n = 9), Australia (n = 8), the United Kingdom (n = 4), and Spain (n = 1). Main outcome measures The median time elapsed between requests for blood components by OR personnel and the retrieval of those components by blood component transport personnel, and the median time elapsed between requests for blood components by OR personnel and the arrival of those components in ORs. Results Participants submitted data on 12 647 units of RBCs, FFP, and PLTs. The median aggregate request-to-retrieval turnaround times (TATs) for RBCs, FFP, and PLTs ranged from 30 to 35 minutes, and the median aggregate request-to-arrival TATs for RBCs, FFP, and PLTs ranged from 33 to 39 minutes. Most of the TAT was consumed by events occurring prior to, rather than after release of components from blood banks. Shorter prerelease TATs were associated with having surgical schedules that listed patients' names and procedures available to blood bank personnel prior to surgeries, and having adequate clotted specimens in the blood bank and completed type-and-screen procedures performed before requests for blood components were submitted to blood banks. Among the fastest-performing 10% of participants (90th percentile and above), request-to-retrieval TATs ranged from 12 to 24 minutes for the 3 blood components, whereas among the slowest-performing 10% of participants (10th percentile and below), request-to-retrieval TATs ranged from 63 to 115 minutes for the 3 components. Median TATs ranged from 33 to 37 minutes for the 3 components. Institutions with TATs in the fastest-performing 25th percentile more frequently stored cross-matched RBCs in the OR daily, stocked PLTs for unexpected surgical use, stored PLTs in or near the OR, and had laboratory rather than nonlaboratory personnel deliver components to the OR than did those institutions with TATs in the slowest-performing 25th percentile. Conclusions Hospital blood bank personnel can deliver blood components to the OR in slightly longer than 30 minutes, measured from the time that those units are requested by OR personnel. Practices aimed at saving time before components are released from blood banks will be more efficient in reducing overall TAT than those practices aimed at saving time after components are released from blood banks. Specific practices associated with shorter blood delivery TATs included providing blood bank personnel with access to the names of surgical patients potentially requiring blood components, having pretransfusion testing completed on those patients prior to surgery, having ample blood products on hand, and having laboratory personnel control blood product delivery.

Quality indicators of fresh frozen plasma and platelet utilization.

To determine the normative rates of expiration and wastage for units of fresh frozen plasma (FFP) and platelets (PLTs) in hospital communities throughout the United States, and to examine hospital blood bank practices associated with more desirable (lower) rates. In 3 separate studies, participants in the College of American Pathologists Q-Probes laboratory quality improvement program collected data retrospectively on the numbers of units of FFP and PLTs that expired (outdated) prior to being used and that were wasted due to mishandling. Participants also completed questionnaires describing their hospitals' and blood banks' laboratory and transfusion practices. One thousand six hundred thirty-nine public and private institutions, more than 80% of which were known to be located in the United States. Quality indicators of FFP and PLT utilization: the rates of expiration and wastage of units of FFP and PLTs. Participants submitted data on 8 981 796 units of FFP and PLTs. In all 3 studies, aggregate combined FFP and PLT expiration rates ranged from 5.8% to 6.4% and aggregate combined FFP and PLT wastage rates ranged from 2.0% to 2.5%. Among the top-performing 10% of participants (90th percentile and above), FFP and PLT expiration rates were 0.6% or lower and FFP and PLT wastage rates were 0.5% or lower. Among the bottom-performing 10% of participants (10th percentile and below), expiration rates were 13.8% or higher and wastage rates were 6.8% or higher. We were unable to associate selected hospital characteristics or blood bank practices with lower rates of FFP and PLT utilization. The rates of FFP and PLT expiration and wastage vary greatly among hospitals in the United States. Hospital blood bank personnel are capable of achieving FFP and PLT expiration and wastage rates below 1%.

Quality Indicators of Fresh Frozen Plasma and Platelet UtilizationThree College of American Pathologists Q-Probes Studies of 8 981 796 Units of Fresh Frozen Plasma and Platelets in 1639 Hospitals

○ Objective.-To determine the normative rates of expiration and wastage for units of fresh frozen plasma (FFP) and platelets (PLTs) in hospital communities throughout the United States, and to examine hospital blood bank practices associated with more desirable (lower) rates. Design.-In 3 separate studies, participants in the College of American Pathologists Q-Probes laboratory quality improvement program collected data retrospectively on the numbers of units of FFP and PLTs that expired (outdated) prior to being used and that were wasted due to mishandling. Participants also completed questionnaires describing their hospitals' and blood banks' laboratory and transfusion practices. Setting and Participants.-One thousand six hundred thirty-nine public and private institutions, more than 80% of which were known to be located in the United States. Main Outcome Measures.-Quality indicators of FFP and PLT utilization: the rates of expiration and wastage of units of FFP and PLTs. Results.-Participants submitted data on 8981 796 units of FFP and PLTs. In all 3 studies, aggregate combined FFP and PLT expiration rates ranged from 5.8% to 6.4% and aggregate combined FFP and PLT wastage rates ranged from 2.0% to 2.5%. Among the top-performing 10% of participants (90th percentile and above), FFP and PLT expiration rates were 0.6% or lower and FFP and PLT wastage rates were 0.5% or lower. Among the bottom-performing 10% of participants (10th percentile and below), expiration rates were 13.8% or higher and wastage rates were 6.8% or higher. We were unable to associate selected hospital characteristics or blood bank practices with lower rates of FFP and PLT utilization. Conclusions.-The rates of FFP and PLT expiration and wastage vary greatly among hospitals in the United States. Hospital blood bank personnel are capable of achieving FFP and PLT expiration and wastage rates below 1 %.

Quality indicators of blood utilization: three College of American Pathologists Q-Probes studies of 12,288,404 red blood cell units in 1639 hospitals.

To determine the normative rates of blood unit crossmatched to transfused (C:T) ratios, red blood cell (RBC) unit wastage, and RBC unit expiration that exist in hospital communities throughout the United States, and to examine hospital blood bank practices associated with more desirable (lower) rates. In 3 separate studies, participants in the College of American Pathologists Q-Probes laboratory quality improvement program collected data retrospectively on the number of transfusion crossmatches performed in their institutions and the number of RBC-containing units that were transfused into patients, the number of units that expired (outdated) prior to being utilized, and the number that were wasted due to mishandling. Participants also completed questionnaires describing their hospitals' and blood banks' laboratory and transfusion practices. One thousand six hundred thirty-nine public and private institutions, well more than 80% of which were known to be located in the United States. Quality indicators of blood utilization (namely, the C:T ratio, the rate of RBC unit expiration, and the rate of RBC unit wastage). Participants submitted data on 12,288,404 RBC unit transfusions. The C:T ratios were 1.5 or less in the top-performing 10% of participating institutions (90th percentile and above), 1.8 to 1.9 in the midrange of participating institutions (50th percentile), and 2.4 or greater in the bottom-performing 10% of participating institutions (10th percentile and below). Red blood cell unit expiration rates were 0.1% or less at the 90th percentile and above, 0.3% to 0.9% at the 50th percentile, and 3.5% or greater at the 10th percentile and below. Red blood cell unit wastage rates were 0.1% or less at the 90th percentile and above, 0.1% to 0.4% at the 50th percentile, and 0.7% or greater at the 10th percentile and below. Depending on which quality indicator was examined, lower values (ie, better performances) were found in institutions that had fewer than 200 hospital beds, no teaching programs, no on-site full-time medical directors of transfusion services, did not utilize maximum surgical blood order schedules, set C:T threshold goals of 2.0 or less, monitored categories of health care workers responsible for RBC wastage, monitored requests for RBC components by transfusion indication, did not accept short-dated units from blood distribution centers, and if they did accept short-dated units, were allowed to return those units to the distribution centers. Hospital blood bank personnel can achieve C:T ratios below 2.0, RBC unit expiration rates below 1.0%, and RBC unit wastage rates below 0.5%. Lower C:T ratios and/or RBC unit expiration rates were associated with blood bank personnel setting C:T thresholds of 2.0 or less, monitoring requests for blood components by transfusion indication criteria, monitoring categories of health care workers responsible for blood wastage, not accepting short-dated units from blood distribution centers, and if short-dated units were accepted, being allowed to return those units to the blood distribution center. These practices were not associated with lower blood wastage rates.

Standardisation of platelet counting accuracy in blood banks by reference to an automated immunoplatelet procedure: comparative evaluation of Cell-Dyn CD4000 impedance and optical platelet counts

Prophylactic and therapeutic platelet transfusions are increasingly used for patients with conditions associated with thrombocytopenia in order to prevent the development of potentially life threatening bleeding. These clinical strategies have led to a significant expansion in platelet unit manufacture, and this now represents a major resource and cost commitment for blood banks. As part of the manufacturing process, blood banks are required to implement control procedures, and the determination of platelet counts in particular is necessary to confirm that the quality of platelet unit production meets the standards defined by national or international guidelines. Apart from linearity analysis and comparisons of platelet counts given by different instruments, there has been no systematic standardisation of platelet counting methods in blood bank practice because to date there has been no suitable reference method for counting platelets in citrate anticoagulants. The recent introduction of an automated immunoplatelet procedure on the Cell-Dyn CD4000 provides a means of determining a true platelet count that is unaffected by changes induced either by storage or anticoagulant. The CD4000 in its routine configuration also provides simultaneous impedance and optical platelet counts and this study was therefore undertaken in order to compare all three different platelet counting methods in parallel with a representative series of platelet units. Platelet counts determined after sub-sampling of platelet units into EDTA vs plain non-anticoagulated tubes revealed no differences in impedance or immunoplatelet counts but generally lower optical counts when aliquoted into tubes that did not contain EDTA. This study therefore routinely used EDTA for platelet unit sub-samples. Comparative results of platelet counts for buffy coat platelet units ( n=36) aliquoted into EDTA indicated that the impedance count was higher than the reference immunoplatelet count by a mean factor of 1.25 while the optical count was lower by a mean factor of 0.87. The degree of impedance count overestimation was particularly consistent while the optical count underestimation was more variable. Linearity studies of 10 fresh platelet units showed no deviation in the range 0– 2305×10 9 l −1 for impedance and 0 to 1420×10 9 l −1 for the optical counts, and the relative numerical relationships between impedance and optical counts were conserved throughout the range of dilutions tested. In the CD4000 optical analysis, blood samples anticoagulated with EDTA showed a distinctive elliptical population distribution that fell within the system thresholds. In contrast, the optical pattern observed for platelet units (in CPD) and ACD-anticoagulated venous blood showed a wider 90° scatter with a population of platelet events above the upper parallel discriminator. As these were excluded from the optical count (but were still identified as platelets by the immunoplatelet method) it meant that the optical counts of samples in citrate-based anticoagulants were systematically lower than immunoplatelet counts. Platelet units ( n=15) analysed daily over a seven day period of storage revealed that the greatest decline in platelet counts was with the optical measurement while the most stable value was obtained by impedance analysis. The results of the immunoplatelet analysis further suggested a progressive increase in small platelets with increasing storage time. The use in this study of a standardised immunoplatelet reference method to examine the question of analyser suitability for determining platelet counts/yields of platelet units thus provided a number of important findings. An impedance platelet counting method is utilised by the great majority of haematology instruments in current use, and in common with the CD4000 analyser, a correction factor is employed to take account of RBC/platelet coincidence. This study found that when analysed samples such as platelet units were RBC-free, that an inappropriate correction factor was applied. Consequently, the CD4000 impedance platelet count will provide reliable platelet counts, irrespective of the day of platelet unit storage, when a factor of 1.25 is applied to the system-reported result. By comparison, optical methods are more likely to be affected by subtle morphological changes that may result from anticoagulants or progressive storage time. The method limitations documented by this study may well affect many other analysers and mean that the implementation of process control statistics related to platelet counts may be less reliable than previously assumed. It is suggested that standardisation could be much better achieved if there was some form of system cross-calibration that was referenced to an independent method such as an immunoplatelet assay. It is proposed that studies of this type should be extended to a wide assessment of platelet count accuracy of blood bank instruments in order to standardise data within national organisations. If consistent inter-instrument correction factors such as those documented here can be identified, it would considerably increase the relevance of determining platelet counts in production control processes.

Alloimmunization in preterm infants after repeated transfusions of WBC-reduced RBCs from the same donor.

Preterm infants are among the most heavily transfused of patient groups, yet multiply transfused infants only rarely produce alloantibodies against RBC or WBC antigens. It is not known whether rates of alloimmunization might be increased by repeated exposure to RBCs and WBCs from the same donor, as in limited-donor-exposure programs, or whether infants might benefit from WBC-reduced RBC components as a means of diminishing the risk of possible alloimmunization. Preterm infants (birth weight 0.6-1.3 kg) received prestorage WBC-reduced RBCs from dedicated donors, collected in AS-3 as a means of limiting donor exposures. Blood samples were collected serially from infants shortly after birth until either discharge or age 6 months and were studied for RBC and WBC antibodies-the latter with reactivity against either HLA class I or neutrophil-specific antigens. Thirty preterm infants received 139 transfusions (mean, 4.6; median, 4 transfusions per infant), with 81 percent of transfusions obtained from one donor per infant. Eighty-four blood samples (mean, 2.7/infant) were studied, and no infant produced RBC antibodies. Twenty-seven percent of infants exhibited WBC antibodies, but only 13 percent actually produced WBC antibodies (passive maternal antibody excluded). Of the WBC antibodies produced by infants, three were against HLA class I and one was against neutrophil-specific antigens; none were linked to adverse effects. Because infants only rarely produce RBC antibodies, no changes in blood banking practices are necessary for limited-donor-exposure programs. Although the production of WBC antibodies by infants occurs, it seems to be uncommon; thus, the possible benefits, if any, of WBC reduction are uncertain, and further study is required before changes in practice can be justified.

Data-driven blood banking practices for neonatal RBC transfusions.

Data-driven blood banking practices for neonatal RBC transfusions.

Dernières mises au point concernant la conservation des concentrés de plaquettes à 4 °C

Summary Under current blood-banking practices, platelet concentrates (PC) can be stored for 5 days from 20 ° to 24 °C. The storage life is essentially limited because storage to 22 °C leads to an increase in the risk of bacterial contamination and to unacceptable lesions of platelets. Therefore, there is considerable interest in developing methods to improve storage conditions. In the past, platelet storage at 4 °C has been extensively studied. The advantages of the refrigerated temperature included an inhibition of the growth of bacterial contaminants and a reduction of metabolic rates which reduce the deleterious effects observed with the storage of platelets at room temperature. Unfortunately, a rapid loss of in vitro functional activity and in vivo viability was observed at 4 °C. This report summarizes storage lesions of PC at 4 °C, and evaluates the effects of a new solution (thrombosol) made up of second messenger effectors. Thrombosol provides a protective effect against in vitro platelet storage lesions and cold-induced activation. Treated platelets stored at 4 °C displayed significantly greater recovery of in vitro activity than did control platelets stored at 22 °C. This is a strong basis that supplementation of platelet concentrates with thrombosol might allow the storage of PC at 4 °C.

Stored red blood cells selectively activate human neutrophils to release IL-8 and secretory PLA2.

Packed red blood cell (PRBC) transfusion has been invoked previously with immunosuppression and increased infections, but it has now been demonstrated that stored PRBCs (>14 days) can prime PMNs and provoke multiple organ failure. Recently, the role of PMNs in the genesis of MOF has been extended to their release of inflammatory cytokines, notably IL-1, IL-8, TNFalpha, and secretory phospholipase A2 (sPLA2). We hypothesize that stored PRBCs can act as a second event via stimulating the release of inflammatory cytokines from PMNs. Isolated human PMNs were incubated for 24 h in RPMI with either 20% fresh plasma or plasma from 42 day old PRBC (day of outdate) and release of IL-8, IL-1beta, TNFalpha, and sPLA2 were measured. Plasma from stored PRBCs contained small amounts of IL-8, sPLA2, and TNFalpha (102.1 +/-5.6 pg/ml, 87.6+/-6.0 pg/ml and 9.7+/-.7 pg/ml). Levels of IL-1beta were below detection (<1 pg/ml). Day 42 PRBC plasma stimulated significant PMN release of both IL-8 and sPLA2 as compared to both control and day 0 plasma (*P < .05), but PRBC plasma did not stimulate PMN release of either IL-1beta or TNFalpha. Transfused blood is emerging as an inflammatory agent that is capable of producing PMN priming. In this study we have demonstrated that PRBC plasma selectively activates PMNs to release both IL-8 and sPLA2. Thus, transfusion of PRBCs may represent a preventable inflammatory insult via modification of both blood banking and transfusion practices.

Management of sickle cell disease: recent advances and controversies.

Management of sickle cell disease: recent advances and controversies.

Blood banking issues pertaining to neonatal red blood cell transfusions

Many preterm infants are given multiple red blood cell transfusions during the early weeks of life. Because firm standards for neonatal transfusions do not exist, it is important to consider the pathophysiology of the anemia of prematurity, the goals of transfusion therapy and blood banking practices that best provide safe and effective neonatal transfusions. There is increasing agreement that efforts continue to minimize phlebotomy blood losses, to transfuse per conservative indications and to limit donor exposure by transfusing stored red blood cells from a single unit reserved for an infant – rather than insisting on fresh blood.

HIV/AIDS and its risk factors in Pakistan

Pakistan currently reports a low prevalence of HIV/AIDS. Concern over the potential for an expanded HIV epidemic in the country is mainly due to segments of the Pakistani population who engage in high-risk practices a low level of public knowledge about HIV/AIDS dangerous blood transfusion and inoculation practices and Pakistans proximity to India a country which has experienced a rapid increase in the prevalence of HIV/AIDS. The limited data currently available on HIV/AIDS prevalence in Pakistan are presented. By November 1996 64 cases of AIDS had been reported to Pakistans National AIDS Program. However the World Health Organization estimated that by the end of 1994 there were really 40000 people infected with HIV. Data from point-prevalence studies suggest that foreign and Pakistani nationals who have either worked abroad or as seafarers may comprise a sizeable proportion of the recognized HIV/AIDS cases. The studies also documented cases of HIV infection among people with multiple sex partners blood transfusion recipients and prisoners. Heterosexual contact appears to be the dominant mode of viral transmission. Lifestyle risk factors and health care practices which contribute to HIV transmission are described.

Feasibility and usefulness of an efficient anti-HBc screening programme in blood donors.

Post-transfusion hepatitis B remains a risk for recipients of hepatitis B surface antigen (HBsAg) screened blood. Anti-hepatitis B core antibody (anti-HBc) screening may help reduce this risk. To evaluate its usefulness, 9,238 East Anglian blood donors were screened for anti-HBc. Those with isolated anti-HBc were identified with two confirmatory anti-HBc and anti-HB surface antibody (anti-HBs) assays. The prevalence of anti-HBc reactions in screening and confirmatory assays was 1.29% and 0.35%, respectively. The level of reactivity was significantly higher when two anti-HBc assays gave concordant results or, being concordant, were anti-HBs positive. All isolated anti-HBc-positive units (0.04%) were negative for additional HBV markers including DNA tested with nested polymerase chain reaction (PCR). A 0.31% prevalence of past HBV infection was found in this population, all carrying both anti-HBc and anti-HBs antibody, most above the protective level (0.1 IU/ml). The proposed screening schemes would limit the number of deferred donors and discarded units and keep the testing time within the remit of routine blood banking practices for an additional cost of approximately 1 pound per unit. However, no evidence was found in this donor population to suggest that anti-HBc screening would significantly reduce the incidence of post-transfusion hepatitis B.

The Retrovirus Epidemiology Donor Study (REDS): rationale and methods.

BY THE SPRING OF 1984, it was clear that AIDS was caused by at least one retrovirus, initially called human T-cell lymphotropic virus, type 111 (HTLV-III), and later called the human immunodeficiency virus (HIV).'.' Shortly after HTLV-111 (HIV) was described, antibody enzyme immunoassays were developed. After these tests were introduced into blood bank practice in March and April of 1985, a significant number of HIV enzyme immunoassay-repeatably reactive results, many later confirmed as true-positive results, were enco~ntered.~ This finding was unexpected and raised serious concern, because blood bankers had believed that most people at high risk for AIDS had voluntarily refrained from donating blood and plasma.4-' In 1985, a second strain of HIV was identified7 and designated HIV-2, with the original virus now called HIV1. A high degree (60-91%) of serologic cross-reactivity was exhibited against the original whole viral lysate enzyme immunoassays for HIV-1 antibodies8 To date, one blood donor infected with HIV-2 has been identified in the United States whose sera reacted with licensed HIV1 antibody screening tests,Y and one blood donor has been identified whose testing patterns suggested reactivity with HIV-2 antigens alone.' No case of transfusion-transmitted HIV-2 has been reported in the United States.' US Abbreviations: HIV-1 and -2 = human immunodeficiency virus type 1 and type 2; HTLV-I and -11 = human T-lymphotropic virus type I and type 11; HTLV-111 = HTLV, type 111, now HIV; MCC = medical coordinating center; NHLBI = National Heart, Lung, and Blood Institute; REDS = Retrovirus Epidemiology Donor Study; RFP(s) = request(s) for proposals; WBC(s) = white cell(s).

Modern Veterinary Blood Banking Practices and their Applications in Companion Animal Practice

There are two main reasons for blood component therapy: the need for an increase in oxygen-carrying capacity and improved hemostasis. Additionally, blood component therapy is used to increase plasma protein concentrations. Component therapy entails separating whole blood into its cellular and plasma components and administering the appropriate blood component based on the patient's needs. General considerations such as compatibility, defined expectations of benefits, and topics including specific disease screening, preparation of blood components, preparation of blood products for administration, and typing and crossmatching in relation to blood component therapy and its application in companion animal practice are discussed.

Minimizing Donor Blood Exposure in the Neonatal Intensive Care Unit: Current Trends and Future Prospects

Limitations in the knowledge of the pathophysiology of anemia contribute to unfounded and liberal transfusion practices in the preterm infant and to uncertain risk-benefit ratios. Researchers have explored an array of strategies to minimize transfusions. Such strategies include collection and banking of autologous placental blood, administration of recombinant erythropoietin, innovations in blood banking practices, and improved definitions of the markers of anemia with more rigorous transfusion guidelines. This article presents an overview of these and other strategies that can be applied as part of an overall approach to limit effectively the number of transfusions in the newborn.

Book Reviews

Book reviewed in this article:Modern Blood Banking and Transfusion Practices. 3rd ed. Denise. M. Harmening, ed.Transfusion Immunology and Medicine. Carel J. van Oss, ed.