Comparison of demographics and motivations of highly committed whole blood and platelet donors

To compare donor demographics and motivations for donation, we surveyed 159 consecutive whole blood donors (WD) and 146 consecutive plateletpheresis donors. All donors had donation experiences of at least 2 gallons (i.e., 16 previous donations). Evaluation of answers to fixed-response and open-ended questions revealed no difference between the two groups in age, type of wages, compensation by employer, “time off” for donation, and church or volunteer organization memberships. The two groups differed in that the platelet donor (PD) group had a higher percentage of males than females (PD group 72.6% males and 27.4% females versus WD group 59% males and 41% females [chi-square = .01]). PDs most often began donating platelets because they were asked (22.6%), demonstrating the importance of active recruitment. When asked why they do not donate platelet products by apheresis, highly committed WDs reported lack of time (25%), lack of knowledge (“Don't know about it,” 21%), lack of recruitment (“No one asked,” 18.5%), or lack of awareness (“Never thought about it,” 5%) as reasons. Factors centering on time constraints, lack of knowledge or awareness about platelet donation by apheresis, and lack of active recruitment prohibit highly committed WDs from entering into plateletpheresis programs. © 1993 Wiley-Liss, Inc.     

Pseudothrombocytopenia in plateletpheresis donors

BACKGROUND: EDTA pseudothrombocytopenia (PTCP) is an in vitro artifact in which the anticoagulation of blood with EDTA is associated with in vitro agglutination of platelets, resulting in a spuriously low platelet count. In apheresis donors, whole-blood samples for complete blood counts are routinely drawn into tubes anti-coagulated with EDTA. STUDY DESIGN AND METHODS: Records of apheresis donors were examined to identify persons in whom the postdonation counts were less than 100 × 10(9) per L. Identified donors were studied to confirm the presence of PTCP by drawing blood samples into EDTA, heparin, and trisodium citrate for serial platelet counts at room-temperature incubation. Platelet counts in citrated plasma were measured before and after the addition of EDTA. A single HLA-matched component from an identified PTCP donor was monitored for response by corrected count increment in the recipient. RESULTS: A total of nine donations were identified, involving 2 donors from a population of 945 donors (prevalence 0.2%). On testing, both donors were confirmed to have PTCP. The addition of EDTA to citrated plasma did not affect the platelet count. Response in a recipient to an HLA-matched component showed an acceptable corrected count increment. CONCLUSION: PTCP may occur in plateletpheresis donors and result in needless medical referral or donor deferral. PTCP does not appear to alter the yield content of the component or to be passively transferred to a recipient.     

Plateletpheresis in 90- to 110-pound donors using the CS-3000 blood cell separator

BACKGROUND: Increases in the use of single-donor apheresis components have increased the need for platelet donors. In the United States, persons must weigh 110 pounds or more to qualify as blood donors, and the same weight limitation has been placed on apheresis donors. Because automated plateletpheresis with some instruments differs considerably from whole-blood donation with respect to the volume of blood removed from the donor, the feasibility of using persons weighing between 90 and 110 pounds as platelet donors was evaluated by the use of the CS- 3000 blood cell separator. STUDY DESIGN AND METHODS: The study was performed using female subjects who met all usual donor requirements except for minimum weight. The standard platelet collection procedure of the instrument was used, except that the blood processing rate was manually selected so as to optimize the blood withdrawal and return rate in individuals. Vital signs were recorded before and after donation as were signs or symptoms of any type of donor reaction. RESULTS: Twenty-six of 28 women completed the donation procedure; in two instances, collection was terminated prematurely because of an inability to maintain adequate venous access. An average of 4.5 × 10(11) platelets were collected during a mean donation time of 110 minutes. All donors tolerated the procedure well, and no serious adverse reactions were seen. Because of the administration of priming solution and anticoagulant during apheresis, there was a net positive fluid balance following the procedure, in spite of the removal of approximately 220 mL of platelet concentrate. CONCLUSION: These preliminary studies suggest that 90- to 110-pound persons may serve as plateletpheresis donors. Additional studies are needed to more fully document the safety and efficacy of this approach. The use of lower- weight donors may significantly increase the number of persons available to provide single-donor platelet components.     

A highly specialized and motivated volunteer population: platelet donors

The plateletpheresis program of the M.D. Anderson Hospital was established in 1963. Approximately 20,000 units of platelet concentrates are produced per year. Credit for the nonreplacement fee generates the greatest number of donors. No organized recruitment campaign exists. Each donor becomes a recruiter for the program. Also involved in donor recruitment are all laboratory personnel, as well as Donor Room exployees.     

Recruiting blood donors into a local bone marrow donor registry

To date, most persons joining bone marrow donor registries have been recruited from platelet-pheresis panels. The potential of recruiting regular blood donors into bone marrow donor registry (BMDR) was explored. It was found that, with minimal effort, 6.2 percent of the age-eligible blood donors were recruited. A distinguishing feature of those who joined the BMDR was a history of frequent blood donations. Although local media attention had a major impact on recruitment, even those joining as a result of the publicity usually were regular blood donors. This program has the potential to recruit nearly 8000 volunteers from 120,000 regular blood donors over an 18-month period.     

Decreased levels of ferritin,mild thrombocytosis,and increased erythropoietin are sequential events among frequent plateletpheresis donors: Implication for a ferritin screen

BackgroundIt is generally recognized that repeat apheresis increases the risk for iron deficiency, thus may impact on the blood homeostasis. With regard to donor vigilance, we clarified the mid- to long-term effects of plateletapheresis by comparing the most frequent donors with the first-time ones in hematological and biochemical tests.MethodsLevels of erythropoietin (EPO), hemoglobin (Hb) and ferritin were analyzed in double-unit (500 mL whole blood or 6 × 10¹¹ apheresis platelets) donations in three male cohorts, with identifiers of first-time whole-blood donors (n = 30), first-time platelet donors transited from maximal whole blood to apheresis (n = 30) and frequent donors subjected to extreme plateletpheresis (n = 90), respectively. According to the number of donations, the last earnest cohort, who donate almost 24 times a year, was further subdivided into three groups– casual (76–120 life-time donations in 5 years), mediocre (121–168 within 7 years) and enthusiastic (≥169 within 7 years and a month).ResultsRegardless of the donation experience in whole blood or plateletpheresis, iron deficiency (serum ferritin concentrations <15 μg/L) was identified in all earnest cohorts. The ferritin means were significantly lower in plateletpheresis groups, with the lowest values in the enthusiastic group. EPO levels showed a significant inverse correlation with ferritin (p = 0.015, r = –0.224). Long-term earnest donors had the lowest iron stores accompanied by a later thrombocytosis and a final increase in EPO was revealed.ConclusionRegular ferritin screens are crucial to ensure a high level of donor health protection.     

Current topics on centrifugal plasmapheresis technologies.

In the field of plasmapheresis centrifugal technology has recently focused on the collection of peripheral blood stem cells (PBSCs) for both autologous and allogeneic transplantation in patients with malignancies or hematological diseases and on donor plasmapheresis. PBSC transplantation is rapidly replacing bone marrow transplantation in such patients. Various kinds of apheresis equipment were applied and described for PBSC collection. Comparison among machines is described. Allogeneic PBSCs were collected from healthy normal donors. Specific attention to the dose and administration duration of granulocyte colony-stimulating factor and a careful apheresis procedure should be made for donor safety. In platelet transfusion practice, a platelet concentrate product derived plateletpheresis from a single donor is preferable to minimize and to prevent adverse transfusion reactions. The status of platelet collection and its efficacy by various kinds of plateletpheresis equipment are discussed. The Amicus and CCS might be preferable plateletpheresis machines because of their collection efficiencies and wider indication for donors. With the limited number of donors, it is essential that plateletpheresis should be more effectively performed and managed by each regional blood center. The status of plasma and red cell collection by apheresis technologies is described also briefly.     

Increase in endogenous thrombopoietin in healthy donors after automated plateletpheresis

BACKGROUND: Thrombopoietin (TPO) is a key cytokine involved in the regulation of megakaryocytopoiesis and platelet production. The aim of the present study was to test whether platelet donation is associated with changes in the serum TPO levels in healthy donors undergoing plateletpheresis. STUDY DESIGN AND METHODS: The study group consisted of 23 healthy donors undergoing single-donor plateletpheresis for the first time. Serum TPO levels and platelet counts were determined before platelet collection, at the end of apheresis, and for 4 days thereafter. Serum TPO levels were determined by a TPO-specific enzyme- linked immunosorbent assay. RESULTS: In relationship to platelet donation, serum TPO levels showed a temporary increase from baseline levels of 69.2 +/? 7.1 pg per mL to 117 +/? 6.8 pg per mL 2 days after plateletpheresis (p < 0.05). Further evaluation revealed a decline in serum TPO levels as platelet counts increased. Female donors showed a delayed normalization of circulating platelet numbers and serum TPO levels as compared to male donors. There was no significant correlation between serum TPO levels and the absolute platelet number during normalization of the donors' platelet counts after plateletpheresis. CONCLUSION: Single-donor plateletpheresis results in a temporary increase in serum TPO levels in healthy platelet donors, which may be part of a compensatory response-boosting megakaryocytopoiesis after platelet collection.     

Lowering the hemoglobin cutoff for female plateletpheresis donors

BACKGROUND: The standards of the American Association of Blood Banks describe a minimum hemoglobin level of 12.5 g per dL for apheresis donors. Until 1995, the authors' institution accepted occasional platelet donors with a lower minimum hemoglobin (11.5 g/dL), if accompanied by medical director approval. STUDY DESIGN: All donation records from a 6-month period before 1995 were retrospectively reviewed to determine whether this lower hemoglobin cutoff adversely affected either the safety of the platelet donation process or donors' subsequent hemoglobin levels. RESULTS: Of 450 donations, 56 (12%, Group 1) were from donors with hemoglobin concentrations between 11.5 and 12.4 g per dL (2 donations from 1 man; 54 donations from 45 women). The remaining 394 donations (88%, Group 2) came from donors with hemoglobin concentrations > or = 12.5 g per dL (216 donations from 118 men; 178 donations from 119 women). The frequency of donor reactions was acceptable (Group 1, 11%; Group 2, 6%); 2 percent of donations by Group 1 donors and 1 percent by Group 2 donors were terminated because of these reactions. Of 46 donors in Group 1, 30 returned to donate platelets again at a later time; at least once, 23 (77%) had a hemoglobin > or = 12.5 g per dL. Ten donors in Group 1 returned for additional donations within 56 days; no meaningful decrease in hemoglobin levels occurred. A hemoglobin cutoff of 12.5 g per dL during the study period would have excluded 1 percent of platelet donations by men and 23 percent by women. CONCLUSION: The data demonstrate that the lower hemoglobin cutoff of 11.5 g per dL is a safe and relevant threshold for accepting female plateletpheresis donors and would allow more participation by women in blood donor programs.     

Apheresis donors and platelet function: inherent platelet responsiveness influences platelet quality

BACKGROUND: Process-induced platelet (PLT) activation occurs with all production methods, including apheresis. Recent studies have highlighted the range and consistence of interindividual variation in the PLT response, but little is known about the contribution of a donors' inherent PLT responsiveness to the activation state of the apheresis PLTs or the effect of frequent apheresis on donors' PLTs. STUDY DESIGN AND METHODS: The relationship between the donors' PLT response on the apheresis PLTs was studied in 47 individuals selected as having PLTs with inherently low, intermediate, or high responsiveness. Whole-blood flow cytometry was used to measure PLT activation (levels of bound fibrinogen) before donation and in the apheresis PLTs. The effects of regular apheresis on the activation status of donors' PLTs were studied by comparing the in vivo activation status of PLTs from apheresis (n = 349) and whole-blood donors (n = 157), before donation. The effect of apheresis per se on PLT activation was measured in 10 apheresis donors before and after donation. RESULTS: The level of PLT activation in the apheresis packs was generally higher than in the donor, and the most activated PLTs were from high-responder donors. There was no significant difference in PLT activation before donation between the apheresis and whole-blood donors (p = 0.697), and there was no consistent evidence of activation in the donors immediately after apheresis. CONCLUSION: The most activated apheresis PLTs were obtained from donors with more responsive PLTs. Regular apheresis, however, does not lead to PLT activation in the donors.     

Sustained decreases in platelet count associated with multiple, regular plateletpheresis donations

BACKGROUND: Transient but significant decreases in platelet counts have been documented to occur in donors undergoing single and serial short-term plateletpheresis collections. The effect of long-term regular plateletpheresis on donor platelet counts has not been characterized. STUDY DESIGN AND METHODS: A retrospective study was performed to evaluate the effects of long-term regular plateletpheresis donation on donor platelet counts. A computerized database containing records of 11,464 apheresis collections from 939 donors over a 4-year period was queried for serial preapheresis platelet counts. Donors were categorized by sex, age, and cumulative number of donations. The average difference in platelet counts (mDeltaPC) between each donor's first and last platelet count during this period was calculated for each category. A subgroup of frequent donors was selected for analysis of mDeltaPC, using the baseline platelet count obtained before the first plateletpheresis procedure. RESULTS: A significant and sustained decrease in platelet count was identified for all donation frequency categories. The frequency of donation correlated directly with decrease in platelet count for all but the highest-frequency donation group, in which deferrals for low platelet count blunted the extent of the mDeltaPC. A mean decrease of 40,000 per microL from baseline occurred in the frequent-donor subgroup. A total of 84 donors (9%) were deferred for low platelet count. The majority returned to donate successfully after temporary deferral. CONCLUSIONS: Regular plateletpheresis donors develop sustained decreases in platelet count. However, clinically significant thrombocytopenia is unusual when rigorous ongoing review and prudent deferral policies are established and followed.     

成都市2010-2015年机采血小板献血者的调查研究

目的 探讨成都市2010-2015年机采血小板捐献现状及其变化趋势,为制定机采血小板采集计划、献血者招募方案和指导临床用血提供科学依据.方法 选择2010-2015年,于成都市血液中心捐献机采血小板的73 106人次无偿献血者为研究对象.通过本中心血站信息管理系统查询、收集及整理机采血小板献血者的年龄、性别、献血人次等资料,计算2010-2015年成都市机采血小板献血人次的发展速度和增长速度,并且采用统计学方法比较不同性别及年龄机采血小板献血者的构成比差异.结果 ①2010-2015年,成都市机采血小板献血人次由6 798人次增加至17 684人次,累计绝对增加量为10 866人次,年平均增长量为2 173人次,年平均增长速度为21.1％.2010-2015年,成都市机采血小板献血人次环比增长速度分别为22.4％、28.4％、31.1％、11.6％和13.2％,其中2012年和2013年环比增长速度较高.②2010-2015年,成都市机采血小板献血者中,男性献血者为52 650人次(72.02％),女性为20 456人次(27.98％),各年男性献血者均多于女性,并且所占比例均＞60％,其中2014年男性献血者所占比例最高,为76.88％(12 010/15 622).2010-2015年,成都市机采血小板献血者性别构成比比较,差异有统计学意义(x2 =691.483,P＜0.001).③2010-2015年,成都市机采血小板献血者中,各年均以18～25岁人群为主要机采血小板献血人群,其中2010年机采血小板献血者中,18～25岁献血人群所占比例最高,为62.80％(4 269/6 798).2010-2015年,18～25岁机采血小板献血者所占比例呈下降趋势,而＞25～30岁和＞30～35岁机采血小板献血者所占比例均呈增加趋势.自2012年起,有年龄为＞55～60岁献血者参与机采血小板献血,2012-2015年该年龄段机采血小板献血者各年所占比例分别为0.46％(49/4 561)、1.09％(153/14 002)、1.42％(222/15 622)及1.19％(210/17 684).2010-2015年,成都市机采血小板献血者不同年龄构成比比较,差异有统计学意义(x2=2 542.556,P＜0.001).结论 2010-2015年,成都市机采血小板献血人次呈逐年增加趋势,各年机采血小板献血者均以男性多于女性,且以18～25岁人群为主要机采血小板献血人群.应根据成都市机采血小板捐献特点,制定科学的机采血小板采集计划和献血者招募方案,确保为临床提供充足、安全的机采血小板制品.     

Volunteer donor apheresis.

Volunteer donor apheresis has evolved from early plasmapheresis procedures that collected single components into technically advanced multicomponent procedures that can produce combinations of red blood cells, platelets, and plasma units. Blood collection and utilization is increasing annually in the United States. The number of apheresis procedures is also increasing such that single donor platelet transfusions now exceed platelet concentrates from random donors. Donor qualifications for apheresis vary from those of whole blood. Depending on the procedure, the donor weight, donation interval, and platelet count must be taken into consideration. Adverse effects of apheresis are well known and fortunately occur in only a very small percentage of donors. The recruitment of volunteer donors is one of the most challenging aspects of a successful apheresis program. As multicomponent apheresis becomes more commonplace, it is important for collection centers to analyze the best methods to recruit and collect donors.     

Voluntary whole-blood donors, and compensated platelet donors and plasma donors: motivation to donate, altruism and aggression.

BACKGROUND AND OBJECTIVES: To establish if voluntary whole-blood donors and compensated platelet donors and plasma donors may differ in their motivation to donate, altruism, aggression and autoaggression. MATERIAL AND METHODS: Whole-blood (n=51), platelet (n=52) and plasma donors (n=48) completed a battery of validated questionnaires while waiting to donate. Bivariate and multivariate analyses of variance and t-tests were performed to detect differences between groups as noted. RESULTS: Altruism (mean=40.2) was slightly higher in whole-blood donors than in platelet (mean=38.3) and plasma donors (mean=39.1) (p=0.07). Blood donors (mean=2.8) scored lower in the spontaneous aggression measure than platelet (mean=4.1) and plasma donors (mean=4.4) (p=0.01). Plasma donors (mean=4.9) had higher auto-aggression than whole-blood donors and platelet donors (mean for both groups=3.4) (p=0.01). Differences between the three groups were mediated by sociodemographic variables (MANCOVA). Whole-blood donors donated to help others, platelet and plasma donors mostly to receive the compensation. However, those platelet and plasma donors, who would continue to donate without compensation were similar in altruism and aggression to whole-blood donors. CONCLUSION: While most platelet donors and plasma donors were motivated by the compensation, those who stated that they would continue to donate without compensation had altruism and aggression scores similar to voluntary whole-blood donors.     

Repeat whole-blood and plateletpheresis donors:unreported deferrable risks, reactive screening tests, andresponse to incentive programs

BACKGROUND: Evaluating plateletpheresis (PPH) and repeat community whole-blood (RWB) donors' responses to donation incentive programs is essential for developing effective donor retention programs. STUDY DESIGN AND METHODS: Using data from a 1998 anonymous questionnaire sent to 92,581 US blood donors, the prevalence of unreported deferrable risks, screening test reactivity, and response to incentives were compared in RWB and PPH donors by the use of weighted chi-square tests and logistic regression analyses. RESULTS: From 52,650 respondents, 38,884 RWB and 2,028 PPH donors were identified. Levels of screening test reactivity (1%) and unreported deferrable risks (UDRs, 2-3%) were similar in RWB and PPH donors. RWB and PPH donors were strongly encouraged or discouraged by similar incentives. Of the incentives that would encourage a higher proportion of UDR-free RWB donors to return, cholesterol screening and earning a blood credit appealed to >50 percent. Similar results were obtained for cholesterol screening in PPH donors. Community service or education credits, premarital screening, and cash had limited appeal for PPH and RWB donors, respectively, and would be more likely to differentially encourage donors with a UDR to return. CONCLUSION: Incentives that were associated with the greatest donor appeal and that minimized the potential recruitment of more risky donors were identified.     

Motivation of plateletpheresis donors

Twenty randomly chosen voluntary plateletpheresis donors were interviewed in depth. Information on their family histories, past histories, present psychosocial adjustment, and history of blood donation was elicited. Most donors had a high level of commitment and drive to achieve, frequently related to low self-image dating from childhood. The act of platelet donation had several important meanings for the subjects. It improved their self-esteem, making them feel more worthy and responsible persons. It provided them with an opportunity to establish relationships with others. The data obtained in this survey suggest that the altruistic behavior of the voluntary donors should be seen both as an act of giving and also one of receiving emotional gratification which fulfills one's important psychological needs. Utilization of these data in recruitment of plateletpheresis donors is suggested.     

Frequent multiunit plateletpheresis from single donors: effects on donors' blood and the platelet yield

Two thousand plateletpheresis procedures performed on 335 donors by either semicontinuous flow centrifu-gation (Haemonetics Model 30) or a multiple bag technique were analyzed for effects on donors and the yield of platelets. The platelet yield was independent of collection method, number of prior donations and donor's hematocrit. It varied directly with the donors' platelet count and was significantly higher for women donating by semi-continuous flow centrifugation. Even at the lowest platelet harvest, the number of platelets obtained was sufficient to meet federal standards for platelet collection procedures. Donor platelet counts decreased following the first multiunit plateletpheresis procedure. After the equivalent of continued alternate day platelet collections the count reached a mean low of 70 per cent as compared to the precollection count, occurring after six to eight donations. The yield was comparably reduced to a mean of 64 per cent. By the tenth donation platelet counts had returned to baseline values, apparently as a result of increased production by the marrow. Similarly, platelet yields returned to higher (i.e. normal) levels. Further donations did not cause platelet counts or yields to vary from normal values. Repeated daily plateletpheresis resulted in more variability in donor platelet counts. Since none of the donors was subjected to this procedure for more than nine consecutive days, marrow response could not be assessed. Comparing number of donations, donor platelet counts and subsequent yields, there was no difference between daily pheresis and an alternate day schedule. Donor hematocrits were not changed by these frequent collections and other side effects were not observed. This study indicates that repeated multiunit plateletpheresis can continuously provide adequate platelet yields without adversely affecting donors.     

Switching iron‐deficient whole blood donors to plateletpheresis

BACKGROUND: Iron deficiency is a frequent side effect of whole blood (WB) donation. In contrast, less red blood cell loss and therefore less iron loss results from plateletpheresis. STUDY DESIGN AND METHODS: WB donors presenting a decrease in either hemoglobin (Hb) or ferritin levels were offered to switch to plateletpheresis with or without iron supplementation. We analyzed the effect of this intervention on deferral rates for an insufficient Hb level in 168 donors. Further, we assessed how this intervention affected Hb and ferritin levels, anemia occurrence, and platelet (PLT) concentrate yields in the donors who presented at least four successive times for thrombapheresis. RESULTS: Switching WB donors to repetitive plateletpheresis procedures resulted in an increase of median Hb (+12 g/L, p < 0.001) and ferritin (+15.5 ng/mL, p = 0.002) values. Anemia and deferral rates were reduced by 23% (p = 0.004) and 13% (p < 0.001). Between high‐ and low‐frequency apheresis donors, no significant differences in Hb and ferritin levels were found. Similarly, discrepancies in Hb and ferritin values between donors that adopted iron supplementation and those who did not were insignificant. The median PLT concentrate yield was 5.43 × 10¹¹ PLTs. CONCLUSION: Switching iron‐deficient WB donors to plateletpheresis was an effective intervention that permitted us to correct low Hb and ferritin levels while retaining donors in our pool.     

青岛地区已知HLA和HPA分型血小板供者库的建立及临床应用

目的建立青岛市已知HLA和HPA分型的无偿机采血小板供者库并用于解决血小板输注无效(PRT)患者的血小板输注。方法采用PCR-SSO流式磁珠法和PCR-SSP法分别对青岛地区无偿机采血小板捐献者1 800人进行HLA-Ⅰ类(A,B位点)、HPA-1—-5,-15基因分型,针对不同免疫状态的PTR患者比较3种不同配型法(血小板随机交叉配型法、抗原特异性配合法、抗原阴性选择法)解决血小板输注无效的效果。结果在高致敏(群体反应性抗体PRA>60%)患者中,HLA和或HPA特异性配型效果较好;轻度致敏(PRA<60%)患者随机交叉,抗原阴性选择,抗原特异性配型方案效果相似。不考虑ABO血型的因素1 800名的血小板供者库可以使99%的患者在库中找到至少1例HLA完全相合的供者,理论估算的供者库规模被不同表型的患者库中检索结果证实。结论理论上青岛本地化已知分型血小板供者库规模需达到6 000人左右可以有效解决血小板输注无效患者的血小板输注问题。只有重度致敏的患者需要HLA完全相同的供者,而轻度致敏的患者可以选择随机交叉配合或抗原阴性选择方案。     

The impact of immediate adverse donation reactions on the return of volunteers undergoing platelet apheresis

IntroductionImmediate adverse reactions experienced during donation decrease return rates among whole-blood donors, but little is known about this effect among platelet apheresis donors. We investigated the impact of immediate adverse reactions on the return rates of volunteer apheresis platelet donors.MethodsIn a sample of 4108 consecutive platelet apheresis donors seen from August 2016 through June 2019, we evaluated whether immediate adverse reactions were associated with returning for a subsequent platelet apheresis donation within a 12-month period. We used propensity score matching to compare donors with and without adverse reactions.ResultsAn immediate adverse reaction occurred in 312 (7.6%) donors; 98.5% were mild, and 0.3% were severe. Of the original 4108 platelet apheresis donors, only 3211 (72.3%) returned for a subsequent donation within 12 months. Experiencing an immediate adverse reaction during the donation process significantly decreased the return rate for a subsequent donation [HR= 0.74 (0.63–0.87)], especially among female donors [HR= 0.70 (0.53–0.93)], donors aged < 30 years [HR= 0.71 (0.54–0.94)], with a high school educational level [0.63 (0.49–0.81)], donors donating for the first time [HR= 0.73 (0.59–0.90)], and repeat donors with a previous platelet apheresis donation more than 180 days prior [HR= 0.68 (0.50–0.93)].ConclusionEven mild adverse events reduce the return rates for a subsequent donation among platelet apheresis donors. Female donors, younger donors, and first-time donors are at higher risk of not returning after an immediate adverse reaction. Preventing the incidence of immediate adverse reactions during platelet apheresis donation may increase the rate of donor retention.