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Motives for joining an unrelated HSC donor registry: description, categorization, and association with donor availability


A challenge for registries of unrelated hematopoietic stem cell (HSC) donors is to recruit and retain sufficient donors for patients needing transplants. Many registered HSC donors opt-out when called as a potential match for a patient. Anecdotal evidence suggests that motives for joining a registry may be linked to the donation decision. The primary goals of this investigation were to describe the range of motives for joining a registry and to examine donor availability by motive type. A diverse sample of 357 potential HSC donors from the Anthony Nolan registry in the UK was asked about their motives for joining and their decision to continue or opt-out after matching a patient was recorded. Motives for joining (N = 557) were first coded and categorized into 17 specific motive types and then arranged along a spectrum from internal to external. Internal values-based motives were most prevalent and availability was highest among potential donors expressing these motives (92%) and lowest among those expressing external motives (pressure, incentives; 0%). Although further research is needed to confirm these findings, they suggest that registries should assess donors’ motives for joining at recruitment in order to conduct follow-up to ensure commitment among those potential members expressing external motives.


The demand for unrelated hematopoietic stem cell (HSC) donors continues to grow due to medical advances that allow the use of HSC transplantation in patients that would not have previously been eligible and increased access to transplantation in multiple countries. There are multiple international registries which help patients to find unrelated HSC donors. One of the central challenges for most HSC donor registries is the ability to ensure that registry members are available when they are called as a potential match for a patient. Availability of registered donors varies from 50–90% across registries depending on registry location, size, and diversity. There have been several investigations into factors associated with potential donor availability [1,2,3,4,5,6,7]. However, an area that has received less attention is registry members’ motivations for initially joining a registry. There is anecdotal evidence that such motives might be linked to donation-related decisions.

Although there has been relatively little work investigating the motives of HSC registry members, our own study of motives among registry members who have previously donated suggested that (a) donors provide distinct motives for their behavior, and (b) self-reported motive types are linked to more/less positive physical and psychological donation experiences [8]. The limited investigation of motives among potential and actual HSC donors is contrasted with much more extensive work in the context of blood donation which has some similarities to HSC donation.

Blood donation research suggests that there are multiple reasons that donors give for donating, including wanting to help others, doing the “right thing”, social obligation, personal benefits, etc. and that these motives are linked both to making an initial donation, as well as to becoming a sustaining donor [9,10,11,12,13]. Additionally, there is evidence that internal values-based (e.g., religious or moral responsibility) reasons are most often cited by blood donors (~85%) as their reason for donating and that external factors are reported less frequently [11, 14, 15]. Although these investigations of blood donors are potentially informative, they may be limited in their application to HSC donation due to some key differences between blood and HSC donation. These differences include the delay between volunteering to donate and actual donation, the urgency of the need for HSCs based on the patient’s condition, matching requirements which link a single donor and patient, and the more intensive medical procedure and longer recovery periods involved in bone marrow donation. Furthermore, to date, these motives have simply been reported, without attempts to place these motives on a broader, superordinate spectrum (e.g., more/less altruistic, more/less empathetic) that might help to explain donor participation and behavior more comprehensively.

A central aim of this survey investigation of HSC registry members at the Anthony Nolan (AN) registry in the United Kingdom was to qualitatively categorize motives for joining the registry into a superordinate dimension from internal to external motives. We chose these endpoints for the continuum because anecdotal evidence in the context of HSC donation suggested that internal, values-based motives for joining (e.g., deeply held religious beliefs) might be more highly associated with long-term commitment to donating than are motives based on external pressure or incentives to join. We defined internal motives as those based on internally held values/beliefs and external motives as those that had clear external source—e.g., non-monetary incentives offered at recruitment or pressure from others to join.

Key goals of this investigation were to (a) describe registry members’ motives for joining the registry, (b) determine whether the motive types that emerged could be arranged along a superordinate internal-external axis, and (c) explore whether motives were associated with potential donor availability at VT. Findings are expected to have implications for both additional research into the relationship between motives and HSC donor behavior and operational decisions in the recruitment and retention of donors.

Materials and methods

Human subjects research protection

This investigation was reviewed and approved by the Institutional Review Board at the University of Pittsburgh and received ethical review and approval from Anthony Nolan. All participants completed informed consent before completing the study interview.

Participants and study design

The current study was conducted in conjunction with the Anthony Nolan (AN) registry in the United Kingdom which has more than 600,000 registry members and which facilitated 1225 donations using AN donors during our 3-year study time period [16]. As part of a broader investigation, we conducted a survey that included an open-ended question about the participant’s motives/reasons for joining the Anthony Nolan registry. Survey data were collected at verification typing (VT) stage—that is, the point at which a potential donor is contacted as a possible match for a patient and decides to either move forward with additional typing and medical work-up as part of the donation process or to opt-out of the registry. The annual percentage of “unavailable” donors at AN across the three study years—including those whom AN could not contact—was approximately 40%. The three largest categories of “unavailable” donors were “donor no-show for medical appointment” (9%), “unable to contact donor” (8%), and “transplant canceled for patient reason” (5%). Approximately 5% specifically opted-out of continued testing and were eligible for participation in our opt-out group.

A random sample of AN members—stratified by their VT decision (continue vs opt-out) and race/ethnicity—who were contacted for VT between April, 2013 and May 2016 after having been identified as a potentially suitable HLA match for a patient in need of a HSC transplant were included. Potential participants had not previously donated bone marrow or peripheral blood stem cells, were between the ages of 16 to 60, and had either decided to continue toward donation or to opt-out of the registry after hearing that they were a potential match for a patient. Potential participants were excluded if they did not speak English or were unable to complete a telephone interview or online survey.

Those who agreed to participate were mailed a paper consent form or directed to a link to an online consent form. If the consent form was not completed within 3 weeks staff from the University of Pittsburgh and Anthony Nolan followed up by email. After consenting, participants were given the option to complete the survey by telephone or online. A Computer Assisted Telephone Interview (CATI) system was used by University of Pittsburgh Survey Research Program staff to collect and directly enter the interview data. Data were cleaned and exported from the CATI system to IBM SPSS Statistics. For those who opted to complete an online survey, a link was emailed and the data was collected using Survey Monkey. All data were stored on secure servers. Participants in the cohort who continued with testing received a £35 honorarium and those in the cohort who opted-out received an honorarium of £35-50 after completing the survey.

Study measures

Participants were asked a series of closed-ended and open-ended questions. The primary focus of this investigation was an open-ended question asking about participants’ main motivation(s) for joining the registry—“In your own words, what motivated you to join the register at that time? The open-ended question allowed participants to list multiple motivations. We thought carefully about whether the unit of analysis should be the individual or the motive statement. Ultimately, we concluded that it is critical to examine the motive statements as the unit of analysis given that (a) our goal was to describe motives and their link to availability, (b) it is reasonable to expect that individuals may have more than one motive for joining the registry, and (c) it is difficult to determine how to treat an individual as the unit if he/she provided more than one motive statement. Therefore, each motive statement was treated as a single unit and the respondent’s availability status was attached to that motive statement. For example, if a person expressed a “sense of duty” motive and a “to help a specific patient” motive and were available at VT, they appear in both those motive categories and contribute to percent available in that category in both the numerator and denominator of the calculation. The overall argument here is that when certain types of motives are expressed—regardless of whether they are expressed along with other motives—they are associated with availability.


Qualitative data resulting from responses to the open-ended question regarding motivation for joining the registry were reviewed independently and then discussed by two members of the research team (AH & JB) to identify key themes in the responses. The goal at this point was not to fit motives into an internal versus external framework, but simply to identify major motive types. Once main and sub-themes had been identified and agreed upon, one coder (AH) coded the open-ended responses. A second coder (JB) independently coded 50% of the responses. The few discrepancies in coding (<15%) were discussed with a third coder adjudicating any remaining coding differences (GS). Through a series of discussions among the co-authors, the motive themes were categorized as clearly internal, mixed, or clearly external. The percent of potential donors available to move forward toward donation was calculated for each motive category.


Participant characteristics

Six hundred and sixty-nine potential donors were randomly selected for participation and 357 completed the survey and described their motives for joining the registry. Participation rates and demographic characteristics are presented in Table 1. The 357 donors reported a total of 557 motives—mean 1.6 and mode 1 motives per person. The majority of donors in our sample (87%) continued with testing after having preliminarily matched a patient.

Table 1 Participant characteristics

Generation of motive categories

Initial review of the motives by a study investigator identified 17 distinct motive categories: (1) personal values, (2) desire to save a life, (3) to make a difference, (4) alternative to donating blood/organs, (5) anticipated positive feelings, (6) easy to donate, (7) sense of duty, (8) ethnic background, (9) responded to public appeal, (10) to help a specific patient, (11) would want someone to be there for me or my family, (12) encouraged by friends/family, (13) inspired by past experience with illness, (14) it was convenient, (15) why not?, (16) feeling pressured, (17) non-monetary incentives. Some motive themes were represented by a single type of motive statement while others had more than one subcategory. For example, the theme personal values contained sub-themes such as commitment to other types of donation (e.g., blood/organ, charity), religious values, and a background in the medical profession or science. Each of these sub-themes was cited as the source of an internal belief/value that served as the motivation to join the registry. Many motive statements had components that fit more than one category and were coded into each motive category they represented, for example: “As a blood donor it is something I have always thought about but never done. The death of an old school friend from Leukemia prompted me to be more proactive”. This motive statement was coded as both “inspired because of past illness” because of the statement about a friend passing away, as well as “personal value” because of the potential donor already donating blood. Finally, it was necessary to make some general rules about coding of motives that sounded relatively similar—e.g., some of those motives that appear in the “personal values” and “desire to save a life” categories. In this case, general statements about saving a life were coded into the category of “desire to save a life”, except when the respondent gave a specific reason for this desire—e.g., moral or religious beliefs—in which case they were coded into the “personal values” category. It should be noted that both of the broader motive categories (Personal values and Desire to save a life) are closely related and are part of the “clearly internal” set of motives.

Three motive statements were too vague to be coded—e.g., “mainly because of the time they said I was a good match for a couple of people they looking for stem cells”, “I joined 30 years ago”, or were statements that only appeared once and were not clearly representative of any of the 16 motive categories—e.g., “I was scared of the procedure, however I feel more confident now so decided to join the registry, it was a change in my attitude”. These statements were excluded from the coding results.

Broad motive types and registry member quotes

Table 2 lists the motive categories and examples of each motive type. At the two ends of the internal-external spectrum—and possibly the best representatives of these categories—were “personal values” (internal) “incentives” (external). Most motives themes were not exclusively internal or external and fell into the mixed category. For example “help a specific patient” is a mixed category because the statements representing this motive type do not reflect either solely internal or external motivation. Personal values, desire to save a life, to make a difference and alternative to blood/organ donation represented motive types that were most clearly internal while incentives and pressure represented motive types that were most clearly external.

Table 2 Motives, quotes and availability of joining of participants

Motive frequency

The most frequently mentioned motive types represented the “sense of duty” category with 151 of all respondents (42%) reporting this motive. Within “sense of duty”, the subgroup “helping those in suffering and need” comprised 92 (61%) of the broader motive type and was the single most mentioned motive. The second most frequently reported motive category was “public appeals” with 63 mentions followed by “personal values” and “desire to save a life”—both of which had 47 mentions.

The least frequently cited motive for joining was “rewards” with only 2 mentions, making up <1% of the motives. This was followed by “alternative to donating blood or organs” with 3 mentions and “pressure” with 5 mentions. Motives categorized as clearly external (“rewards” and “pressure”) were mentioned 7 times (1.3% of total motives). Clearly internal motives were mentioned 105 times (18.9% of total motives).

Motives and decision at testing

We examined the percent availability among the potential donors who reported clearly internal, mixed, or clearly external motives. Availability was 91.8% for registry members who reported clearly internal motives for joining the registry (105 total clearly internal motives mentioned), 86.5% for individuals who reported motive types that were mixed (445 total mixed motives mentioned), and 0.0% for those with clearly external motives (7 total clearly external motives mentioned). There were no clear differences by gender or ethnic group in terms of the frequency or types of motives cited for joining the registry.


This investigation set out to describe self-reported motives for joining an HSC registry, to determine whether we could categorize those motives along an internal-external spectrum, and to examine their association with decisions about whether to continue with or opt-out of continuing a testing. It is one of the first to examine the role of motives in the context of HSC donation, and extends our previous work in this area.

The majority of motives for joining the registry fell in the mixed internal–external categories. The fact that “sense of duty” was the most commonly mentioned motive category seems to indicate that many registrants joined the registry as a way to give back and help those around them. External motives were given least often and made up the smallest percentage of motive types—a finding that is similar to those in blood donation [14,15,16]. However, it is likely that these external motives are substantially underrepresented in this dataset as fewer opt-out donors—who were the only members to report these motive types—participated in this investigation. The finding that the majority of motives were internal or mixed likely reflects the recruitment messages and contexts used by the Anthony Nolan registry in its appeals to potential donors and reflects the type of person who is more likely to join.

Although our categorization of motive types along the spectrum from internal to external involves a degree of subjectivity, we did find that we were able to arrange motive types generally into three broader categories along this continuum. Most motives fell in the middle category of mixed internal/external and it is possible that a larger volume of data from similar populations would allow for further internal/external gradations within that middle category. Inclusion of more registry members who opted-out of donation could also provide a richer variety of motives that are clearly external.

The drop in availability along the spectrum from clearly internal to clearly external suggests that targeting for recruitment people with strong personal values about helping others is likely a beneficial strategy for HSC registries although additional research will need to determine if this holds true across different societies and sociocultural backgrounds. Recruitment at sites where people who are more naturally prone to thinking about helping others such as at blood drives, religious venues, and charity events may result in more committed and available registry members. Tailoring messages to reinforce the possible good a person can do may help in increasing the longer-term commitment of potential donors and reduce attrition.

The finding that none of the group of individuals reporting clearly external motives—such as pressure or rewards—was available when contacted as a potential match for a patient is striking. Although incentives such as “glow in the dark bands” mentioned by one study participant are likely to boost recruitment, it seems clear that individuals who are motivated to join by such incentives are unlikely to be committed to actual donation for donation requests that happen much later. In other words, the incentive for joining the registry is transient and immediate and similar incentives are not offered when a member is called sometime later to actually consider donating. Furthermore, although it may be difficult to recognize or limit pressure from peers/family, recruitment staff themselves can ensure that they are being encouraging without applying undue pressure to join. Removing pressure/rewards as incentives to join will likely result in a smaller but more committed set of registry members. An additional strategy could be to directly ask individuals their motivations for joining at recruitment and to use evidence of external motivations to intervene early such as providing more information regarding the donation process with the potential donor to address concerns, and confirming their commitment to join.

A potential limitation to this investigation is the low number of opt-out participants in the survey. Although multiple attempts were made to contact selected participants of this group such as by calling at different times of the day and contacting via post and email many did not reply. The low number of opt-out participants means that perhaps some motivation types in this group are underrepresented. It is also clear that our decisions about coding motive categories along the internal-external spectrum were somewhat subjective. Both the motive categories and their status as internal, mixed, or external will require further investigation with additional samples of HSC registry members. A second potential limitation is the retrospective nature of the motive reporting. However, the demonstrated links between stated motives and behavior in this and other investigations suggests that motives are an important element to examine in this context. Finally, the coding of qualitative statements and the naming of categories, by nature, involves some degree of subjectivity. While the broader finding that availability declines as we move from clearly internal to clearly external motives provides some validity evidence for our motive categorization strategy, additional research will need to be conducted to fully confirm or refine the motive subcategories.

In conclusion, we believe that these findings are novel in the field of HSC and have implications for the importance of motive expression on member availability. Internal motives seem to be strongly associated with willingness to continue toward donation while external motives are associated with the opposite. The role of motives in the donation experience should be examined further as a potential tool to improve donor management strategies.


The contents do not reflect the views of the Department of Veterans Affairs or the United States Government.


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This project was supported by funds from Anthony Nolan.

Author contributions:

All authors participated in the design of the research, selection of the analytic strategy, and manuscript preparation. B.S., C.A., A.B., and A.O. facilitated sampling and participant recruitment and data management at Anthony Nolan. J.B. and G.P. collected and managed data at the University of Pittsburgh. A.H., G.S., J.B., and G.P. analyzed the data. All authors interpreted data and reviewed and approved the final manuscript.

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Correspondence to Galen E. Switzer.

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La Casta, A.H., Shaw, B.E., Anthias, C. et al. Motives for joining an unrelated HSC donor registry: description, categorization, and association with donor availability. Bone Marrow Transplant 54, 425–431 (2019).

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