Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Donating blood on a regular basis appears to reduce blood pressure, but appearances can be deceiving

BACKGROUND

Previous studies have reported a relationship between blood donation and decreased risk for cardiovascular events, and it has been proposed that this may be due to a lowering of blood pressure among hypertensive individuals who donate on a regular basis.

STUDY DESIGN AND METHODS

With the use of a retrospective longitudinal analysis, predonation blood pressure readings were examined across consecutive whole blood donations for New York Blood Center donors. With blood pressure levels recorded at the first, second, third, and fourth donations, the sample was divided into three subgroups including high (≥140 mmHg), intermediate (>100 and <40 mmHg), and low (≤100 mmHg) systolic blood pressure (SBP). In addition, a computational approach was used to estimate regression to the mean effects for donors with high SBP or high diastolic blood pressure (DBP) at their first, second, or third donation.

RESULTS

Visual examination of SBP and DBP patterns across donations revealed that, on average, donors with extreme values at one donation had relatively normal values at the other donations. Further, comparison of computed expected versus observed blood pressure decreases supported the notion of a subsequent regression to the mean among donors with elevated SBP or DBP at Donation 1, 2, or 3.

CONCLUSION

Among individuals who are hypertensive at initial donation, reductions in blood pressure at subsequent donations appear to result from regression to the mean as opposed to a salutary physiologic process.

Prolonged red cell storage before transfusion increases extravascular hemolysis

BACKGROUND

Some countries have limited the maximum allowable storage duration for red cells to 5 weeks before transfusion. In the US, red blood cells can be stored for up to 6 weeks, but randomized trials have not assessed the effects of this final week of storage on clinical outcomes.

METHODS

Sixty healthy adult volunteers were randomized to a single standard, autologous, leukoreduced, packed red cell transfusion after 1, 2, 3, 4, 5, or 6 weeks of storage (n = 10 per group). 51-Chromium posttransfusion red cell recovery studies were performed and laboratory parameters measured before and at defined times after transfusion.

RESULTS

Extravascular hemolysis after transfusion progressively increased with increasing storage time (P < 0.001 for linear trend in the AUC of serum indirect bilirubin and iron levels). Longer storage duration was associated with decreasing posttransfusion red cell recovery (P = 0.002), decreasing elevations in hematocrit (P = 0.02), and increasing serum ferritin (P < 0.0001). After 6 weeks of refrigerated storage, transfusion was followed by increases in AUC for serum iron (P < 0.01), transferrin saturation (P < 0.001), and nontransferrin-bound iron (P < 0.001) as compared with transfusion after 1 to 5 weeks of storage.

CONCLUSIONS

After 6 weeks of refrigerated storage, transfusion of autologous red cells to healthy human volunteers increased extravascular hemolysis, saturated serum transferrin, and produced circulating nontransferrin-bound iron. These outcomes, associated with increased risks of harm, provide evidence that the maximal allowable red cell storage duration should be reduced to the minimum sustainable by the blood supply, with 35 days as an attainable goal.REGISTRATION. ClinicalTrials.gov NCT02087514.

FUNDING

NIH grant HL115557 and UL1 TR000040.

Applying self-determination theory to the blood donation context: The blood donor competence, autonomy, and relatedness enhancement (Blood Donor CARE) trial

The Blood Donor Competency, Autonomy, and Relatedness Enhancement (Blood Donor CARE) project was designed as a practical application of self-determination theory to encourage retention of first-time donors. Self-determination theory proposes that people are more likely to persist with behaviors that are internally-motivated, and that externally-motivated behavior can evolve and become internalized given the appropriate socio-environmental conditions. According to self-determination theory, motivation to engage in blood donation may become increasingly self-determined if the behavior satisfies fundamental human needs for competence (a sense of self-efficacy to achieve specific goals), autonomy (a sense of volitional control over one's behavior), and relatedness (a sense of connection to a larger group). The primary aim of this randomized controlled trial is to examine the effect of competence, autonomy, and/or relatedness interventions on donor retention. Using a full factorial design, first-time donors will be assigned to a control condition or one of seven intervention conditions. Donation competence, autonomy, and relatedness, along with additional constructs associated with return donation, will be assessed before and after the intervention using online surveys, and donation attempts will be tracked for one-year using blood center donor databases. We hypothesize that, compared to the control condition, the interventions will increase the likelihood of a subsequent donation attempt. We will also examine intervention-specific increases in competence, autonomy, and relatedness as potential mediators of enhanced donor retention. By promoting first-time donor competence, autonomy, and relatedness our goal is to enhance internal motivation for giving and in so doing increase the likelihood of future donation.

Immune Regulation of sickle Cell Alloimmunization

Red blood cell (RBC) transfusion remains an important treatment for patients with sickle cell disease (SCD) and the majority of patients receive transfusions by adulthood. However, SCD patients are at a high risk of alloimmunization, which can cause life-threatening complications. The high rate of alloimmunization can in part be explained by chronic inflammatory condition in SCD characterized by significant immune and inflammatory activation. Heightened immune effector cell responses and/or impaired regulatory networks are likely to drive alloantibody production in alloimmunized SCD patients. In support of this, altered T cell immunoregulation, known to control antibody responses, have been reported in alloimmunized SCD patients. In addition, stronger follicular help T cell responses that help antibody production by B cells were described in alloimmunized as compared to non-alloimmunized SCD patients. Furthermore, several innate immune abnormalities have been identified in alloimmunized SCD patients, including a compromised anti-inflammatory response against extracellular cell free heme. The data support a model in which alloimmunized SCD patients are unable to switch off their proinflammatory state in response to the ongoing hemolytic state characteristic of SCD, placing this patient subset at a higher risk to develop a strong immune response against allogeneic determinants on transfused RBCs, thus increasing the risk of further alloimmunization. A detailed mechanistic understanding of innate immune abnormalities that can contribute to pathogenic T cell responses in alloimmunized SCD patients will lay the foundation for identification of biomarkers of alloimmunization with the goal that this information will ultimately help guide therapy in these patients.

Storage characteristics of multiple-donor pooled red blood cells compared to single-donor red blood cell units

BACKGROUND

Each unit of blood donated is processed and stored individually resulting in variability in the amount of red blood cells (RBCs) collected, RBC properties, and the 24-hour posttransfusion RBC survivability. As a result, each unit differs in its ability to deliver oxygen and potentially its effects on the recipient. The goal of this study was to investigate the storage of pooled RBCs from multiple donors in comparison to control standard RBC units.

STUDY DESIGN AND METHODS

Two units of irradiated, leukoreduced RBCs of same ABO, D, E, C, and K antigen phenotype were collected from each of five donors using apheresis. One unit from each donor was pooled in a 2-L bag and remaining units were used as controls. After being pooled, RBCs were separated in five bags and stored at 4°C along with the controls. Quality indexes were measured on Days 2, 14, and 28 for all the units.

RESULTS

Adenosine triphosphate assays for both pooled and controls showed a slight decrease from Day 2 to Day 28 (pooled/control from 5.22/5.24 to 4.35/4.33 µmol/g hemoglobin [Hb]). 2,3-Diphosphoglycerate was successfully rejuvenated for all RBC units on Day 28 (pooled 11.46 µmol/g Hb; control 11.86 µmol/g Hb). The results showed a nonsignificant difference between pooled and control units, with a general trend of lower standard deviation for pooled units when compared to controls.

CONCLUSION

Pooled units have reduced unit-to-unit variability. Future exploration of their immunogenicity is required before using pooled units for transfusion.

Survey of Irradiation Practice for the Prevention of Transfusion-Associated Graft-versus-Host Disease

Context.—Transfusion-associated graft-versus-host disease is a rare, often fatal complication of cellular blood product transfusion. The requirement that at-risk groups receive irradiated products reduces the incidence of transfusion-associated graft-versus-host disease. A comprehensive survey of irradiation practices has not been performed since 1989; meanwhile, new indications for irradiation have emerged.

Objective.—To assess current irradiation practices at College of American Pathologists member institutions. Changes in irradiation practice indicated by comparing results of a survey of irradiation practices in 1989 with those of a survey performed in 2014 may reveal how the field has developed and what areas (if any) remain to be improved.

Design.—A supplemental College of American Pathologists survey was sent out with questions regarding irradiation practices for specific conditions and circumstances. The questions included conditions for which irradiation is generally considered required for the prevention of transfusion-associated graft-versus-host disease as well as those not considered to be a special risk.

Results.—An average of 2100 organizations responded to each question regarding their irradiation practices. Irradiation for transfusion from blood relatives, human leukocyte antigen–matched products, preterm infants, and Hodgkin disease were the most common indications cited. A few organizations had universal irradiation, whereas others irradiated products by floor/unit or by service.

Conclusions.—For some at-risk populations irradiation of cellular blood products is more common than in 1989, whereas for others this practice has been reduced. Although gains have been made since the last national survey of irradiation practices, work remains to eliminate the possibility of transfusion-associated graft-versus-host disease from known at-risk populations.

Impact of Uniform Methods on Interlaboratory Antibody Titration Variability: Antibody Titration and Uniform Methods

Context.—Substantial variability between different antibody titration methods prompted development and introduction of uniform methods in 2008.

Objective.—To determine whether uniform methods consistently decrease interlaboratory variation in proficiency testing.

Design.—Proficiency testing data for antibody titration between 2009 and 2013 were obtained from the College of American Pathologists. Each laboratory was supplied plasma and red cells to determine anti-A and anti-D antibody titers by their standard method: gel or tube by uniform or other methods at different testing phases (immediate spin and/or room temperature [anti-A], and/or anti-human globulin [AHG: anti-A and anti-D]) with different additives. Interlaboratory variations were compared by analyzing the distribution of titer results by method and phase.

Results.—A median of 574 and 1100 responses were reported for anti-A and anti-D antibody titers, respectively, during a 5-year period. The 3 most frequent (median) methods performed for anti-A antibody were uniform tube room temperature (147.5; range, 119–159), uniform tube AHG (143.5; range, 134–150), and other tube AHG (97; range, 82–116); for anti-D antibody, the methods were other tube (451; range, 431–465), uniform tube (404; range, 382–462), and uniform gel (137; range, 121–153). Of the larger reported methods, uniform gel AHG phase for anti-A and anti-D antibodies had the most participants with the same result (mode). For anti-A antibody, 0 of 8 (uniform versus other tube room temperature) and 1 of 8 (uniform versus other tube AHG), and for anti-D antibody, 0 of 8 (uniform versus other tube) and 0 of 8 (uniform versus other gel) proficiency tests showed significant titer variability reduction.

Conclusion.—Uniform methods harmonize laboratory techniques but rarely reduce interlaboratory titer variance in comparison with other methods.

Zika Virus and the Blood Supply: What Do We Know?

Zika virus (ZIKV), a mosquito-borne Flavivirus and emerging infectious disease, is the focus of an international public health emergency after its rapid spread through the Americas and the Caribbean. Although most ZIKV infections are subclinical or characterized by mild febrile illness, ZIKV has been implicated in severe complications, most notably microcephaly in babies born to incident infected mothers during pregnancy. As yet, the extent to which ZIKV is transfusion transmissible remains undefined. Nonetheless, a high prevalence of asymptomatic infection during outbreaks, the demonstration of ZIKV in blood donors, and 4 possible cases of transfusion-transmitted ZIKV in Brazil have raised concern for risk to the blood supply. Consequently, a proactive response is underway by blood collection agencies, regulatory bodies, national funding agencies, and industry alike. Mitigation strategies differ between endemic and nonendemic areas. In the continental United States, the American Association of Blood Banks and Food and Drug Administration guidelines recommend travel-based deferral for those returning from affected areas, and nucleic acid testing is being initiated under an investigational new drug application in Puerto Rico and selected areas of the United States. Options are less clear for countries where autochthonous vector-borne transmission is active. The burden of Zika falls in low-resource countries where high cost and technical barriers associated with testing and pathogen reduction pose barriers to implementation. Additional strategies include maintaining selective inventory for high-risk recipients (eg, pregnant women). We review the available data as of July 2016 on ZIKV in relation to the blood supply including risk, mitigation strategies, and barriers to implementation in addition to the research that is needed to address current uncertainty.

Motivations for donating and attitudes toward screening policies in US blood donors with viral infection

BACKGROUND

Differences in motivating factors that contribute to the decision to donate blood between infected and uninfected donors may help to identify areas for improving donor education.

STUDY DESIGN AND METHODS

As part of a risk factor study, confirmed-positive donors (cases) based on serology-only (human T-lymphotropic virus [HTLV]) or serology and nucleic acid testing (NAT) or NAT-only (human immunodeficiency virus [HIV], hepatitis B virus [HBV], hepatitis C virus [HCV]), and serology-unconfirmed, NAT-negative false-positive donors (controls) were asked about motivations and opinions toward blood donation. "Test seeking" was inferred if a donor answered "yes" to "I wanted to get my test results" and one of the following: "blood center testing is confidential," "free," "more accurate than other test centers," or "tests will identify problems with my blood." Cases were compared to controls using descriptive and multivariable analyses.

RESULTS

Whether a case or control, the most common donation reason was "to help someone in need" (>90% in each group). After adjusting for demographic characteristics, test seeking was not significantly associated with infection status. Test seeking was more common in first-time, younger males and nonwhite, non-Hispanic donors. Of donors with HIV, 13% considered selection policies to be unfair, compared with 1, 2, 0.5, and 6% of donors with HBV, HCV, and HTLV and controls, respectively (adjusted odds ratio for HIV cases vs. controls, 3.9; 95% confidence interval, 2.3-6.7).

CONCLUSIONS

Most donors give to help those in need, including HIV-positive donors. Our results establish a baseline from which additional studies can be compared focused on alternate ways to reduce noncompliance and improved messaging to ensure that high-risk potential donors understand the reasons for blood donor screening policies.

Serologic screening of United States blood donors for Babesia microti using an investigational enzyme immunoassay

BACKGROUND

The tick-borne pathogen Babesia microti has become recognized as the leading infectious risk associated with blood transfusion in the United States, yet no Food and Drug Administration-licensed screening tests are currently available to mitigate this risk. The aim of this study was to evaluate the performance of an investigational enzyme immunoassay (EIA) for B. microti as a screening test applied to endemic and nonendemic blood donor populations.

STUDY DESIGN AND METHODS

The study aimed to test 20,000 blood donors from areas of the United States considered endemic for B. microti and 10,000 donors from a nonendemic area with the investigational B. microti EIA. Repeat-reactive samples were retested by polymerase chain reaction (PCR), blood smear, immunofluorescent assay (IFA), and immunoblot assay. In parallel, serum samples from symptomatic patients with confirmed babesiosis were tested by EIA, IFA, and immunoblot assays.

RESULTS

A total of 38 of 13,757 (0.28%) of the donors from New York, 7 of 4583 (0.15%) from Minnesota, and 11 of 8363 (0.13%) from New Mexico were found repeat reactive by EIA. Nine of the 56 EIA repeat-reactive donors (eight from New York and one from Minnesota) were positive by PCR. The specificity of the assay in a nonendemic population was 99.93%. Among IFA-positive clinical babesiosis patients, the sensitivity of the assay was 91.1%.

CONCLUSION

The B. microti EIA detected PCR-positive, potentially infectious blood donors in an endemic population and exhibited high specificity among uninfected and unexposed individuals. The EIA promises to provide an effective tool for blood donor screening for B. microti in a format amenable to high-throughput and cost-effective screening.

A prospective evaluation of chronic Babesia microti infection in seroreactive blood donors

BACKGROUND

Babesia microti is the foremost infectious risk to the US blood supply for which a Food and Drug Administration (FDA)-licensed test is unavailable for donation screening. Characterization of the antibody response to B. microti and correlation with parasitemia is necessary to guide screening and donor management policies.

STUDY DESIGN AND METHODS

During an FDA licensure trial, blood donors were prospectively screened (July-November 2013) using a B. microti-specific antibody enzyme immunoassay (EIA, Immunetics) in highly endemic (New York [NY]; n = 13,688), moderately endemic (Minnesota [MN]; n = 4583), and nonendemic (New Mexico [NM]; n = 8451) regions. Blood donors with repeat-reactive (RR) results participated in a 12-month prospective cohort study using B. microti EIA, immunofluorescent assay, polymerase chain reaction (PCR), blood smear, and clinical questionnaire.

RESULTS

Thirty-seven (61.67%; 24 NY, seven MN, six NM) of 60 eligible RR donors enrolled in the study; 20 of 37 (54%) completed the 12-month follow-up visit of which 15 (75%) were still seroreactive. Nine PCR-positive donors were identified during index screening; five participated in the follow-up study, three were PCR positive at 6 months, and two remained positive at final follow-up (378 and 404 days). Most RR donors displayed low-level seroreactivity that was either stable or waning during follow-up. The level and pattern of reactivity correlated poorly with PCR positivity.

CONCLUSION

The findings indicate prolonged seropositivity in blood donors. Although rare, asymptomatic, persistent PCR positivity supports the current policy of indefinite deferral for donors with a history of babesiosis or positive test results. Repeat testing by PCR and serology will be necessary if reinstatement is to be considered.

Evidence of relative iron deficiency in platelet- and plasma-pheresis donors correlates with donation frequency

BACKGROUND

The loss of iron stores and resulting iron deficiency is well documented in whole blood or red blood cell donors. We hypothesized that relative iron deficiency also occurs as a result of more frequent platelet- and plasma-pheresis (apheresis) donation.

MATERIALS AND METHODS

To test this hypothesis, we proposed a pilot cross-sectional study to analyze erythropoiesis- and iron-related parameters in white male apheresis donors: (1) relative to controls, (2) in correlation with apheresis donation frequency, and (3) in correlation with pre-donation platelet count.

RESULTS

Fifty eligible apheresis donors and eight controls were enrolled in the study. Apheresis donors were found to have a lower serum ferritin and serum hepcidin and exhibited evidence of iron restricted erythropoiesis relative to controls. Furthermore, among donors, lower MCV, CH^r , hepcidin concentration, and serum ferritin were observed in more frequent apheresis donors. Correlations between donation frequency and hepcidin and ferritin were noted in apheresis donors.

CONCLUSIONS

This pilot study demonstrates that apheresis donors are relatively iron deficient compared to controls and supports the premise that frequent apheresis donation correlates with relatively iron restricted erythropoiesis. An analysis of iron- and erythropoiesis-related parameters in a broader population of frequent apheresis donors (i.e., female and non-white donors) may demonstrate larger deficits and an even greater potential benefit of iron replacement. J. Clin. Apheresis 31:551-558, 2016. © 2015 Wiley Periodicals, Inc.

A brief motivational interview with action and coping planning components enhances motivational autonomy among volunteer blood donors

BACKGROUND

In contrast to standard donor retention strategies (e.g., mailings, phone calls, text messages), we developed a brief telephone interview, based on motivational interviewing principles, that encourages blood donors to reflect upon their unique motivators and barriers for giving. This study examined the effect of this motivational interview, combined with action and coping plan components, on blood donor motivations.

STUDY DESIGN AND METHODS

The design was to randomly assign blood donors to receive either a telephone-delivered motivational interview with action and coping plan components or a control call approximately 6 weeks after their most recent donation. Participants completed a series of surveys related to donation motivation approximately 3 weeks before telephone contact (precall baseline) and then repeated these surveys approximately 1 week after telephone contact (postcall).

RESULTS

The sample was 63% female, included a majority (52.6%) of first-time blood donors, and had a mean age of 30.0 years (SD, 11.7 years). A series of analyses of variance revealed that, relative to controls (n = 244), donors in the motivational interview group (n = 254) had significantly larger increases in motivational autonomy (p = 0.001), affective attitude (p = 0.004), self-efficacy (p = 0.03), anticipated regret (p = 0.001), and intention (p = < 0.001), as well as larger decreases in donation anxiety (p = 0.01), from precall baseline to postcall assessment.

CONCLUSION

This study supports motivational interviewing with action and coping planning as a novel strategy to promote key contributors to donor motivation.

Retrospective analysis of community hospital red blood cell recovery procedures: improved utilization needed for effectiveness

BACKGROUND

Perioperative blood recovery (PBR) is an important component of patient blood management. We analyzed our experience providing PBR for community hospitals to determine procedure types and clinical variables associated with efficacy and cost-effectiveness.

STUDY DESIGN AND METHODS

PBR cases (>25,000) from January 2008 through December 2012 were analyzed. For each procedure type, the median number of returned red blood cell units (rRBCs) and ratio of cases with at least 1 to less than 1 rRBC unit were calculated. Clinical predictors of rRBC were identified by linear and logistic regression.

RESULTS

The overall median rRBC was 0.29 units despite median estimated blood loss (EBL) of 350 mL. Only three of 31 common procedure types had ≥1:<1 rRBC ratios near to or higher than 1. In nine of 31 common procedure types, at least 50% of cases had no rRBC return. Linear regression demonstrated significant association of rRBCs with increased EBL, longer operative duration, surgeon, PBR device type (autoLog vs. CS5), and decreasing age. EBL, autoLog use, high surgeon case volume, vascular procedures, and emergent versus elective procedures associated with higher odds of at least 1 rRBC.

CONCLUSION

Discrepancy between rRBC and EBL and high percentages of cases with no rRBC suggests that PBR technique and case selection need optimization. Identification of procedure types and variables associated with PBR efficacy (≥1 rRBC) should improve utilization of PBR. Association of autoLog use with higher rRBC warrants further investigation.

Determination of Babesia microti seroprevalence in blood donor populations using an investigational enzyme immunoassay

BACKGROUND

Transfusion-transmitted babesiosis caused by Babesia microti has emerged as a significant risk to the US blood supply. This study estimated the prevalence of B. microti antibodies in blood donors using an investigational enzyme immunoassay (EIA).

STUDY DESIGN AND METHODS

A peptide-based EIA that detects both immunoglobulin (Ig)G and IgM antibodies to B. microti was developed and validated. Donor samples randomly selected from areas defined as high-risk endemic, lower-risk endemic, and nonendemic for B. microti were deidentified and tested using the investigational EIA. Samples that were EIA repeat reactive were further tested by B. microti immunofluorescent assay (IFA), polymerase chain reaction (PCR) on red blood cell lysates, and peripheral blood smear examination. A random subset of 1272 samples from high-risk endemic areas was tested by IFA, PCR, and peripheral blood smear in parallel with EIA.

RESULTS

Among 15,000 donations tested with the investigational B. microti EIA, EIA repeat-reactive rates were 1.08% (54/5000) in a high-risk endemic area, 0.74% (37/5000) in a lower-risk area, and 0.40% (20/5000) in a nonendemic area. After application of a revised cutoff, these values were reduced to 0.92%, (46/5000), 0.54% (27/5000), and 0.16% (8/5000). Overall concordance between EIA and IFA among donor samples was 99.34%. One seropositive sample was positive by PCR.

CONCLUSION

The seroprevalence of B. microti in blood donors in a high-risk area measured by an investigational EIA was approximately 1%. The EIA shows promise as an efficient high-throughput blood donor screening assay for B. microti.

The value of area-based analyses of donation patterns for recruitment strategies

BACKGROUND

Lack of ready access to a donation site may be a potential barrier to or influence the frequency of blood donations. In this study, we applied geographic analysis to blood donor behavior and use of different donation sites.

STUDY DESIGN AND METHODS

The study population consisted of blood donors who gave whole blood in Georgia between 2004 and 2008. Zip code, city, and county of donor's residence were matched with the addresses of their donation sites. Donors were dichotomized as either nonmetro Atlanta or metro Atlanta residents. Six donation site categories were defined: donation within the same or a different zip code, within the same or a different city, and within the same or a different county. Logistic regression was used to compare donations by zip code, city, and county.

RESULTS

The study population consisted of 402,692 blood donors who donated 1,147,442 whole blood units between 2004 and 2008, more than half of whom (56.4%) resided in the metro Atlanta area. The majority of donors were white (75.0%) and female (55.7%). In nonmetro Atlanta, repeat donors were more likely to have donated at fixed sites (p < 0.001). In metro Atlanta, repeat donors were more likely to have donated at a mobile site than at a fixed site (p < 0.001).

CONCLUSION

Geographic and demographic differences in blood donation patterns exist. The locations of donor residences and blood donation sites influence donor behaviors. Understanding the geographic influence on donation patterns provides an important tool for optimizing donor recruitment strategies.