Donors and blood collection - Practice in Blood Centres and Hospitals

Practical Transfusion Medicine 4th Ed.

19. Donors and blood collection

Ellen McSweeney¹ & William G. Murphy^1,2

¹ Irish Blood Transfusion Service, National Blood Centre, Dublin, Republic of Ireland

² Health Service Executive, Clinical Strategy and Programmes, and University College Dublin, Republic of Ireland

Collecting blood from people for transfusion to others is not optional – it is an essential part of healthcare. A developed healthcare system needs to provide approximately 30–40 therapeutic units of red cells and up to six therapeutic doses of platelets annually per thousand of the population it serves. There is no satisfactory alternative therapy in most cases and no prospect of any such alternative emerging soon.

Blood donors: paid, directed, payback and altruistic

People can be motivated to donate blood in three different ways: (1) as a direct response to the needs of an individual they care about, (2) for an economically valued reward or (3) as an altruistic act. All three methods are in wide use today. All have their drawbacks. However, it has by now become clear that societies that succeed in establishing a mature programme of altruistic donations generally gain a more secure and stable supply of safer blood for transfusion than those that do not. There is compelling evidence that the incidence and prevalence of infectious diseases are higher among donors who donate for personal economic gain. There is also some evidence that individuals who are directly approached by a relative or friend to donate for a particular patient are more likely to withhold critical information about their personal infectious risk history that may compromise the safety of the recipient of the donation.

Motivation, recruitment and retention of altruistic donors are not easy or cheap. In most developed nations 5% or less of the population donates per year. While donors will queue for hours in times of clear perception of need, such as in a major disaster, most of the time blood services need to work hard to maintain supply. Establishing a mature altruism-based blood donation and collection programme requires a high degree of social cohesion and an immense effort in education and communication. Maintaining a programme once it is established may also need considerable effort and expense. Many successful national or regional programmes based on altruism were set up around the middle of the 20th century, at a time of national need in conflict or post-conflict. The appeal of sharing health and well-being was relatively easily conflated with national military or civil requirements at that time. Countries that did not establish altruism-based blood services to begin with have tended to find it much more difficult to establish one afterwards, and often remain dependent on nonaltruistic donations. Huge efforts are currently being made to redress this throughout the developing world, often directed towards younger adults (Chapter 24).

Paying blood donors will provide a supply of blood, but it requires enough people in the population for whom the payment on offer provides sufficient motivation. Students or other economically marginalized individuals will often provide blood or plasma for payment, but the strategy will limit overall supply where there are not enough economic marginals in the community to respond. In more developed economies the balance of high demand for blood for transfusion with limited numbers of people who will be motivated by the rewards on offer often makes paying for donations an inadequate strategy. In addition, paying for blood also undermines the alternative, more successful motivation of altruism in these economies.

Apart from the problems of supply, paid donors are, in general, a less safe source than volunteer donors. Data comparing disease markers between paid and nonpaid donors reflect this difference in safety. In an analysis of 28 published data sets, it was found that while the incidence of disease markers had diminished over the years between 1977 and 1996 for paid and unpaid donors alike, unpaid donors were on average 5–10 times safer than paid donors and that this difference had not changed over time (see van der Poel et al., in Further Reading). The logic is compelling: people who genuinely feel well, and have no great incentive to donate other than genuine regard for their fellow humans, will tend not to withhold risk information, or at least not return regularly even if they do. People who need money or items of small economic value at the level they may be offered by blood services will have more pressing needs and are more likely to withhold relevant risk information. In addition, increased at-risk exposure from drug addiction or sex working occurs more frequently at the lower economic margins of a Westernized society.

A system of directed and payback donations, where donors are recruited among the relatives and friends of the patient requiring blood transfusions, also provides some supply. Such an approach will generally be insufficient to support a well-developed healthcare system and is prone in places to covert payments to donors, including professional donors.

European Union (EU) Directive 2002/98/EC (see Further reading) instructs member states to promote community self-sufficiency in human blood and blood components and to encourage voluntary unpaid donations of blood and blood components.

Whereas starting a career as a blood donor is mainly driven by external stimuli, becoming a committed regular donor requires a high level of intrinsic motivation. It is essential that the donor sees him/herself as a dedicated donor and that donating becomes a habit. Key strategies that blood services must consider in blood donor retention programmes include active communication with the donor from the beginning, making donation convenient, reducing donor anxiety and adverse reactions, having well-trained and motivated staff, and encouraging temporarily deferred donors to return as soon as possible following the expiry of their deferral period. These measures enable blood services to convert first-time donors to regular committed donors, a primary goal of donor management [1].

Challenges still remain in recruiting donors from ethnic minorities. Migrant populations have different disease patterns with different transfusion demands. Added to this, data suggest that migrants tend not to become blood donors in their new country. A number of factors may contribute to the proportionally low representation of minorities in the donating population, including culture, lack of social/ethnic identification, fear and lack of information.

Donor management in Europe

Almost 50 blood establishments from 34 European countries contributed to the development of the DOMAINE Donor Management in Europe Project (see Further reading) to analyse practices in donor management in Europe. The project compiled a Donor Management Manual and developed a Training Programme to provide tools for blood establishments to optimize practice in their local context. The manual covers development and usage of donor recruitment and retention strategies, organization of blood donor sessions, blood donor data management and donor counselling, in addition to donor management in relation to patients needing multiple transfusions, human resources issues, training, information technology and ethical issues.

Risks to the blood donor

Blood donation is generally very safe. Most people can readily tolerate venesections of approximately 10% of their blood volumes without apparent harm or significant physiological compromise. However, it is not a trivial undertaking and requires considerable care to minimize the risk to the donor. This is particularly the case since there is no proven health benefit to the donor except in the treatment, inadvertent or otherwise, of haemochromatosis. The risks associated with blood donation are listed in Table 19.1.

Table 19.1 Adverse events or reactions in blood donors.

Type of event or reaction	Incidence
Vasovagal events or reactions
Dizziness, nausea, simple fainting, severe faint with prolonged loss of consciousness and convulsions; associated trauma from falls or vehicle accidents	1.4–7% moderate reactions rate* 0.1–0.5% severe reaction rate*
Hospitalization rate	1 per 198 000 donations* Two-thirds of these are due to vasovagal reactions
Needle injury
Sore arm	12.5% females, 6.9% males*
To the vein, causing pain and bruising, which may be extensive, thrombophlebitis, thrombosis	9–23%*
To the artery, causing extensive bruising, fistula, aneurysm, distal ischaemia, compartment syndrome	0.003–0.011%*
To the nerve, causing pain, and motor and sensory loss, which can be prolonged	0.016–0.9%* 0.0022% (disablement)*
To a tendon, causing acute and intense pain	Rare
Serious cardiovascular events or reactions
Angina, myocardial infarction, cerebrovascular accident	Very rare; may or may not be causally related to the donation; always associated with underlying pre-existing disease
Iron deficiency with or without anaemia
Even in the absence of anaemia, tissue iron deficiency may be associated with mild disturbance of cerebral function, such as impaired concentration, and with sleep disturbance/restless legs	Regular blood donors: iron depletion >20%* Absent iron stores 15%* Frequent donors:Absent iron stores: males 16.4%, females 27.1%*
Allergic reactions/anaphylaxis
Reactions may be to the skin preparation materials or adhesives, or to latex in the attendants' gloves	Rare
In apheresis donors in addition to the above
Citrate toxicity from the anticoagulant	Mild reactions are common 80%* Severe reactions are rare 0.4%*
Thrombocytopenia and protein deficiency from excessive platelet or plasma donations respectively	Rare and easily prevented
Allergic reactions to ethylene oxide used in the sterilization of the harness	Rare
Haemolysis/air embolus due to errors in the procedure or problems with the manufacturing of the harness	Very rare
For granulocyte donors: allergic reactions to hetastarch if used as a sedimentation agent or adverse drug reactions to steroids or growth factors used to raise the donor's leucocyte count	Mild reactions including bone pain are common with the use of growth factors and steroids in donors. Many blood services do not provide granulocytes by apheresis. Pooled buffy coats provide an alternative that is logistically simpler, safer for the donor, and may be equally efficacious
*When marked with an asterisk, the figure is from Reference [10].

An internationally accepted description and classification of adverse events and reactions was proposed by the European Haemovigilance Network (EHN) and the International Society of Blood Transfusion (ISBT) in 2004 and refined in 2008. They classified complications into two main categories: those with predominately local symptoms, such as haematomas, nerve injuries and tendon injuries, and those with predominately generalized symptoms, such as vasovagal reactions. Complications specific to apheresis procedures were categorized separately. Complications were further graded into mild, moderate and severe, and were assigned an imputability score for the likelihood of blood donation being the cause of the reaction.

Some complications are specific to apheresis donations, e.g. citrate reactions, haemolysis, air emboli and allergic reactions to ethylene oxide used in the sterilization of the harness. The majority of apheresis donors experience mild citrate reactions, such as a metallic taste or tingling in the lips. This is an accepted occurrence, considered to be an inevitable effect of the anticoagulant. Most blood establishments will only report citrate effects if they are severe or if they result in the donation being discontinued.

Longer term consequences of donation, such as iron depletion with or without associated anaemia, psychological consequences of false positive reactions in screening assays or increased bone resorption, as has been reported in apheresis donors, are not currently reported as complications of donation, but this may change given time.

The overall incidence of complications directly related to blood donation is often quoted as being approximately 1%, though the reported rate of reactions may be much less than the true reaction rate. One study where information on adverse events was actively sought on follow-up rather than relying on passive collection of spontaneous reports by donors reported that from 1000 randomly selected donors three weeks after donation 36% of donors had had one or more adverse events: fatigue (7.8%), vasovagal symptoms (5.3%), nausea and vomiting (1.1%), along with bruising (22.7%), soreness (10%) and haematomas (1.7%) at the venepuncture site [2]. Of complications collated by the EHN/ISBT Working Group 99% belonged to four categories: vasovagal reactions (86% of all complications), haematomas (13%), nerve injuries (1%) and arterial punctures (0.4%) [3].

Rarely severe complications arise, such as accidents related to vasovagal reactions and nerve injuries with long-lasting symptoms. These can have serious consequences for the donor and can impact on his/her daily life. Vasovagal reactions that occur after the donor has left the session are of particular concern. Such delayed reactions are thought to account for 10% of all vasovagal reactions and occasionally death has been attributed to accidents following them. A retrospective analysis of Danish data relating to 2.5 million donations found that severe complications occurred with an incidence of 19 per 100 000 procedures; two-thirds of which were due to vasovagal reactions with loss of consciousness and one-third due to needle insertion [4].

Young age, first time donor status and low total blood volume are independent predictors of higher reaction rates. A complication rate of 10.7% in 16 and 17 year olds, 8.3% in 18 and 19 year olds and 2.8% in donors aged 20 years and older has been observed, as has a higher incidence of donation-related injury (particularly physical injury from syncope-related falls) in 16 and 17 year olds compared with older donors. Syncope occurred in 4 in 1000 donations and injury in 6 in 10 000 donations in this age group and almost half of the injuries that occurred in American Red Cross regions involved 16 to 17-year-old whole blood donors [5].

It is unlikely that the risks to blood donors can ever be reduced to zero. Coupled with the societal necessity for blood donations, this places a significant ethical burden on blood services to use their best endeavours to reduce the risks. This includes particular attention to detail, careful collation and analysis of data on the incidence and nature of adverse events or reactions, and proper management of the information derived, e.g. by sharing and comparing data among blood services to identify and promote best practices. The uneven risk-to-benefit ratio for blood donors also places an ethical responsibility on healthcare givers, the users of blood donations, to avoid wastage and unnecessary use of blood transfusions.

Several strategies can be taken to reduce the risk of complications occurring during and after donation. Efforts to improve the donation experience are crucial not only to ensure the health and well-being of blood donors but to sustain an adequate blood supply. Even minor reactions discourage donors from donating again and syncope, particularly if associated with injury, profoundly decreases the return rate of donors. Good needle insertion techniques are critical to reduce the incidence and severity of venepuncture-related complications. Other successful strategies include pre-donation education, optimizing the session environment, appropriate selection criteria (particularly as regards estimated blood volume), vigilant supervision of donors by staff, water ingestion before donation, distraction techniques and muscle tension during phlebotomy, and post-reaction instructions to donors [6].

Donor selection and exclusion

Prospective blood donors are subjected to a process, often specified in national legislation, intended to minimize the risks to the donor and to the eventual recipient of the donated blood. This involves a donor history to identify clinical conditions in the donor that may suggest increased risk to the donor of a serious adverse event/reaction if the donation goes ahead or any recognizable risk in the donor for transmitting infectious agents to the recipient. Infectious risks from donors are listed in Table 19.2, along with available donor exclusion strategies to address these risks.

Table 19.2 Infections risks from blood donors.

Categories of risks	Examples of infections	Donor exclusions that may reduce risk
Failure of a test to detect an infectious agent where it should have done so: while this risk is very low, it is not zero and provides a reason to continue strict exclusion practices in the presence of increasingly sensitive testing methods	HIV 1 and 2, hepatitis C, hepatitis B	Excluding at-risk donors identified by questions about risk activities in the past: e.g. drug use or high risk sexual activity at any time in the past
Window-period infections: a donor is infectious with an agent for which the donation is routinely tested, but the infection was acquired so recently that the donor does not yet have detectable infectivity in the blood	HIV 1 and 2, hepatitis C, hepatitis B	Excluding at-risk donors identified by questions about risk activities in the recent past: e.g. recent at-risk sexual activity, recent tattoos or piercings or recent invasive procedures
Infections for which donors are not routinely tested	Malaria, West Nile virus, Chagas' disease, visceral leishmaniasis, vCJD, dengue	Excluding donors, where possible, on the basis of travel or previous residence. This is very difficult in areas of high prevalence and endemicity, and requires additional testing where possible
	Any recently acquired infection that the donor has not yet cleared and that may have a viraemic or bacteraemic phase	Excluding donors on the basis of a recent history of any febrile illness; excluding donors who have recently had a live virus vaccination
Known diseases in the donor's past that may have an unknown transmissible element	Cancer, autoimmune diseases	Excluding donors with a previous history of cancer, with the exception of some localized and cured forms
		Excluding donors with a history of a multisystem autoimmune disease
Risks from unrecognized yet-to-emerge infectious agents	In the recent past HIV and HCV were extensively spread by blood transfusions before the true nature of the diseases became apparent. A similar fate could have arisen with vCJD	Excluding donors with a history of conditions strongly associated in the past with the early and extensive spread of emerging diseases with long incubation periods. Such donors include sex workers and intravenous drug users
		More contentiously, excluding men who have previously had sex with men at any time in their past
		Excluding donors who have previously received blood transfusions
		Excluding xenotransplant recipients
Risk from transmissible spongiform encephalopathies	All prion diseases are considered to have the possibility of an infectious blood phase	Excluding donors who have a strong family history of spongiform encephalopathy
		Excluding donors who have been treated with human-derived pituitary hormones or dura mater
		Outside the UK and Europe, exclusion on the basis of residence in higher risk countries during the BSE epidemic
		In some European countries previous recipients of blood transfusions are excluded to try to limit the risk of transfusion-acquired vCJD

In some services the donor undergoes some form of physical examination, but this is often cursory and abbreviated and, among altruistic donors at least, is of doubtful value in someone who has provided satisfactory answers to a detailed history.

Donors generally undergo a measurement of their haemoglobin level at some point, either prior to the donation or, in some countries, on a sample taken at the same time as the donation. This is either from a skin puncture (‘capillary sample’) or a venous sample. This measurement of haemoglobin serves two purposes – it provides some protection to the donor against having a pre-existing anaemia made worse by donating and it helps ensure that the final therapeutic product will have a minimum red cell content. It might also help prevent acute adverse reactions or events in the donor, but there is no evidence that this is the case. The cut-off levels for the allowable haemoglobin level in the donor vary between blood services and regulatory authorities and are empirically derived. Often, as in the European Union (EU) rules (Directive 2004/33/EC, see Further reading) a different level is used for males and females, with the allowable minimum haemoglobin level set 1 g/dL higher for males than for females. Haemoglobin levels vary in the same individual between capillary and venous blood [7], with the seasons and the time of day, and with posture and activity. In addition, measuring haemoglobin levels does not provide protection against nonanaemic iron deficiency.

Where a blood service is subject to legally binding regulations, donor exclusions may be specified by law. In the EU the specifications are generally interpreted as a minimum requirement by the member states or the national blood services; in the USA and other jurisdictions, in contrast, the specifications are generally regarded as a maximum requirement by the blood service operators, who rarely add to them on their own initiative. The EU requirements for permanent and temporary exclusion of donors are listed in Table 19.3; the blood services in many countries routinely exceed these requirements, sometimes on the basis of local epidemiological risks and sometimes on the basis of national or regional perceptions of best practice. For example, exclusions on the basis of sexual risk, travel, haemochromatosis or previous transfusions vary from country to country in the EU, while remaining within the legal specification defined in the EU Directives.

Table 19.3 Deferral criteria for donors of whole blood and blood components. Reproduced from Commission Directive 2004/33/EC of 22 March 2004 implementing Directive 2002/98/EC of the European Parliament and of the Council as regards certain technical requirements for blood and blood components, OJ L 91, 30.3.2004, http://eur-lex.europa.eu, © European Union, 1998–2012.

1 Permanent deferral criteria for donors of allogeneic donations

Cardiovascular disease

Prospective donors with active or past serious cardiovascular disease, except congenital abnormalities with complete cure

Central nervous system disease

A history of serious CNS disease

Abnormal bleeding tendency

Prospective donors who give a history of a coagulopathy

Repeated episodes of syncope or a history of convulsions

Other than childhood convulsions or where at least 3 years have elapsed since the date the donor last took anticonvulsant medication without any recurrence of convulsions

Gastrointestinal, genitourinary, haematological, immunological, metabolic, renal or respiratory system diseases

Prospective donors with serious active, chronic or relapsing disease

Diabetes

If being treated with insulin

Infectious diseases

Hepatitis B, except for HBsAg-negative persons who are demonstrated to be immune

Hepatitis C

HIV-1/2

HTLV I/II

Babesiosis (*)

Kala-azar (visceral leishmaniasis) (*)

Trypanosomiasis cruzi (Chagas' disease) (*)

Malignant diseases except in situ cancer with complete recovery

Transmissible spongiform encephalopathies (TSEs) (e.g. Creutzfeldt–Jakob disease, variant Creutzfeldt–Jakob disease)

Persons who have a family history that places them at risk of developing a TSE, or persons who have received a corneal or dura mater graft, or who have been treated in the past with medicines made from human pituitary glands. For variant Creutzfeldt–Jacob disease, further precautionary measures may be recommended.

Intravenous (IV) or intramuscular (IM) drug use

Any history of nonprescribed IV or IM drug use, including bodybuilding steroids or hormones

Xenotransplant recipients

Sexual behaviour

Persons whose sexual behaviour puts them at high risk of acquiring severe infectious diseases that can be transmitted by blood

2 Temporary deferral criteria for donors of allogeneic donations

2.1 Infections. Duration of deferral period

After an infectious illness: prospective donors shall be deferred for at least 2 weeks following the date of full clinical recovery. However, the following deferral periods shall apply for the infections listed in the table:

Brucellosis (*): 2 years following the date of full recovery

Osteomyelitis: 2 years after confirmed cured

Q fever (*): 2 years following the date of confirmed cured

Syphilis (*): 1 year following the date of confirmed cured

Toxoplasmosis (*): 6 months following the date of clinical recovery

Tuberculosis: 2 years following the date of confirmed cured

Rheumatic fever: 2 years following the date of cessation of symptoms, unless evidence of chronic heart disease

Fever > °C: 2 weeks following the date of cessation of symptoms

Flu-like illness: 2 weeks after cessation of symptoms

Malaria (*):

· individuals who have lived in a malarial area within the first 5 years of life:

3 years following return from last visit to any endemic area, provided person remains symptom free; may be reduced to 4 months if an immunologic or molecular genomic test is negative at each donation;

· individuals with a history of malaria: 3 years following cessation of treatment and absence of symptoms; accept thereafter only if an immunologic or molecular genomic test is negative;

· asymptomatic visitors to endemic areas: 6 months after leaving the endemic area unless an immunologic or molecular genomic test is negative;

· individuals with a history of undiagnosed febrile illness during or within 6 months of a visit to an endemic area: 3 years following resolution of symptoms; may be reduced to 4 months if an immunologic or molecular test is negative. West Nile virus (WNV) (*): 28 days after leaving an area with ongoing transmission of WNV to humans.

2.2 Exposure to risk of acquiring a transfusion-transmissible infection:

· endoscopic examination using flexible instruments;

· mucosal splash with blood or needlestick injury;

· transfusion of blood components;

· tissue or cell transplant of human origin;

· major surgery;

· tattoo or body piercing;

· acupuncture unless performed by a qualified practitioner and with sterile single-use needles;

· persons at risk due to close household contact with persons with hepatitis B; defer for 6 months or for 4 months provided a NAT test for hepatitis C is negative;

· persons whose behaviour or activity places them at risk of acquiring infectious diseases that may be transmitted by blood; defer after cessation of risk behaviour for a period determined by the disease in question and by the availability of appropriate tests.

2.3 Vaccination

Attenuated viruses or bacteria: 4 weeks

Inactivated/killed viruses, bacteria or rickettsiae: no deferral if well

Toxoids: no deferral if well

Hepatitis A or hepatitis B vaccines: no deferral if well and if no exposure

Rabies: no deferral if well and if no exposure. If vaccination is given following exposure defer for 1 year

Tickborne encephalitis vaccines: no deferral if well and if no exposure

2.4 Other temporary deferrals

Pregnancy: 6 months after delivery or termination, except in exceptional circumstances and at the discretion of a physician

Minor surgery: 1 week

Dental treatment:

Minor treatment by dentist or dental hygienist (note that tooth extraction, root-filling and similar treatment is considered as minor surgery): defer until next day

Medication: based on the nature of the prescribed medicine, its mode of action and the disease being treated

3 Deferral for particular epidemiological situations

Particular epidemiological situations (e.g. disease outbreaks):

Deferral consistent with the epidemiological situation (these deferrals should be notified by the competent authority to the European Commission with a view to Community action)

4. Deferral criteria for donors of autologous donations

Serious cardiac disease: depending on the clinical setting of the blood collection

Persons with or with a history of:

· hepatitis B, except for HBsAg-negative persons who are demonstrated to be immune

· hepatitis C

· HIV-1/2

· HTLV I/II

Member states may, however, establish specific provisions for autologous donations by such persons. Active bacterial infection.

The tests and deferral periods indicated by an asterisk (*) are not required when the donation is used exclusively for plasma for fractionation.

Deferral rates vary in different blood services. Reported deferral rates in EU blood services range from 0.5 to 25.2% of donors, with a mean of 10.9%. The lowest deferral rates are in countries where the public knowledge of blood donation selection criteria is high – where donors may register online and complete an eligibility questionnaire in advance. A low haemoglobin level is typically the commonest reason for deferral, accounting for nearly 40% of deferrals. Other factors include relative proportions of new and regular donors, urban versus rural venues and sessions with a majority of younger donors in whom deferrals for skin piercing, tattooing and travel are higher.

Iron deficiency in blood donors

Blood donation results in a significant iron loss of approximately 200–250 mg per donation. Both iron deficiency causing anaemia and iron deficiency in the absence of anaemia are common among donors, particularly though by no means exclusively, in females of

child-bearing age. Iron depletion below a ferritin level of 12 μg/L can be present even when there is no evidence of iron-deficient erythropoiesis. It may cause poor concentration and sleep disturbances, and has been associated with restless legs syndrome. Iron deficiency also arises in donors of plasma or platelets by apheresis due to the red cell losses from blood samples and from the residual amounts of blood in the collection harness. A study of 1535 male and 1487 female Australian blood donors showed that 5.3% of males and 18.9% of females who met the EU criteria for haemoglobin levels were iron deficient as defined by a serum ferritin level of less than 12 μg/L. The prevalence of iron deficiency among the general female population in Australia is 5–7% and is negligible among the general male population [8]. Similar findings were noted in a US study [9].

Iron deficiency among donors may be prevented or treated by adequate intake of oral iron. However, optimum regimens for iron prophylaxis or therapy among blood donors have not been generally defined and practice varies considerably. Options include regular measurement of blood or plasma indices of iron deficiency, routine provision of iron supplements, particularly to female donors, and dietary advice. Fears about the risk of serious iron toxicity in children who accidentally take a donor's iron tablets are probably well founded: iron should be dispensed with adequate warnings, packaging and advice when it is supplied.

Large-scale studies and technical developments will be required to optimize the approach to screening donors to prevent morbidity from anaemia and iron deficiency.

The blood collection/donation process

Assessing the donor, collecting and storing the information obtained, collecting the unit of blood and the accompanying blood samples, and storing and transporting the collected blood are all critical manufacturing steps in the preparation of the final therapeutic product. The entire process needs to be controlled within a functioning quality system, while maintaining the humanity of the process, and especially the dignity of the donor. The venue must be clean, warm, but not excessively so, uncluttered, bright and without excessive noise. Staff should not be distracted or distressed by extraneous events. There must be appropriate space available for confidential discussions between donors and staff. The flow of the donor from reception through registration, interview, haemoglobin check if done, and venesection should be orderly and unidirectional. Allocation of numbers and labels for the units collected must be rigorously controlled; a mix up in labels between units or between samples is a potentially fatal error. Materials used in the collection clinic – bags, antiseptic wipes, mixer-weighers, haemoglobinometers, etc. – must all be controlled.

Several blood services do not take a blood collection from a donor on their first attendance. Instead, they take a sample for blood group, blood count and virus screen. This practice almost guarantees that a unit of blood will not be mislabelled with the wrong ABO group provided an automated check against historical donor records is in place; it also provides some protection against window period donations from people who are donating for the purposes of getting an HIV or hepatitis test. It is, however, very costly – a significant proportion of blood in most services come from first time and once-only donors.

Preparation of the venepuncture site must also be rigorously controlled to reduce the risk of bacterial contamination; this is discussed in Chapter 14. This process and indeed all collection activities should be subject to regular audit.

Donors may be recruited or retained to donate for apheresis as well as, or instead of, whole blood. Apheresis may be for red cells, usually as a double dose from larger donors, platelets or plasma, or combinations of these. Donor acceptance or rejection criteria are similar to those for whole blood donors, though plasma donors may be exempted for some infectious risks (Table 19.3). Platelet and plasma donation intervals are shorter. Since patients receiving apheresis platelets, and to a lesser extent apheresis red cells, receive fewer donor exposures, there is a benefit to using these components as much as possible. For selected products, such as HPA-1a negative platelets, apheresis is the only viable approach. Apheresis is generally a more expensive method of providing components than whole blood collection and processing, but the economics vary from place to place. In addition, apheresis donation can be a very effective way of maximizing the return to a blood service from many of its committed donors.

Much of the plasma used in the manufacture of blood components comes from apheresis donors, many of whom are paid and who can donate up to twice weekly. Populations of paid plasma donors have a higher prevalence and incidence of infectious disease markers than nonremunerated donors, but since the early 1990s blood component manufacture has had a very good safety record from the point of view of transmission of infectious diseases. This has been achieved by increased donor screening and exclusion procedures, advances in testing, including the introduction of nucleic acid testing for viruses, and effective methods of pathogen removal or inactivation, such as pasteurization, solvent detergent treatment and nanofiltration. As things stand at present, the supply of manufactured blood components worldwide could probably not be maintained without paid plasma donation, though several countries have in the past supplied their national needs for blood components from nonremunerated donors, and several of these still do.

Obligations to donors

Although donors are well and are not seeking care, they are subjected to a healthcare intervention from the moment they begin to complete the history questionnaire. The blood service enters a contract with them and develops an ethical obligation to them from the very start of the first attendance. The service's main duty of care is to the recipient of the donation, and it cannot compromise that, but it has obligations to the donor that must also be discharged. Donation is not a right, but rights accrue to the donor once the process is embarked upon.

The donor has a right:

· to confidentiality and autonomy;

· to informed consent;

· to protection from harm – this includes not being made to feel unhealthy when they are merely outside donation specifications;

· to receive the results of tests when these are of significance to their health;

· they are entitled to receive direction and counselling around the results of such tests;

· they must be protected as much as possible from adverse events or reactions by the use of adequate facilities, adequately trained staff, provision of clear and accurate information, and 24-hour access to advice after donation.

In turn, donors are required:

· to identify themselves correctly;

· to be truthful in their answers to the screening questions – in some countries this obligation is explicitly stated to have the force of the law behind it; and

· to inform the blood service if any change arises in their health after they have donated.

In some services, donors are also provided with a form or a phone number they can use if they have knowingly withheld important information during the screening process that they have been too embarrassed to give at interview. This process, termed confidential unit exclusion, is still in use in some countries. It may provide some protection against donations in the window period, but it may also encourage donors to withhold information at the point where it should be given; this in turn would compromise blood safety.

Donors also have some rights in relation to the use of their donation – the consent that they give must include the possibility that the donation may not be used for the therapeutic use that they assume, but that it might expire unused or be used for control purposes. Where a unit of blood is collected specifically for control, test or calibration purposes, the donor is entitled to be asked to give explicit consent for that. Lastly, donors have a right to expect that healthcare providers will take account of the unique nature of the medicine that they are using, and ensure ethical and appropriate use.

Key points

1. The incidence and prevalence of infectious diseases are higher among donors who donate for personal economic gain.

2. Iron deficiency is common among donors; it can occur in the absence of anaemia and even of iron-deficient erythropoiesis and may cause symptoms such as poor concentration and sleep disturbances.

3. Assessing the donor, collecting and storing the information obtained, collecting the unit of blood and the accompanying blood samples, and storing and transporting the collected blood are all critical manufacturing steps in the preparation of the final therapeutic product.

4. The donor has a right to confidentiality and autonomy, informed consent and protection from harm.

5. Clinicians should take account of the unique nature of blood components as a medicine, so as to avoid wastage and ensure appropriate use.

References

1. Ringwald J, Zimmermann R & Eckstein R. Keys to open the door for blood donors to return. Transfus Med Rev 2010; 24: 295–304.

2. Newman PH & Roth AJ. Estimating the probability of a blood donation adverse event based on 1000 post donation interviewed whole-blood donors. Transfusion 2005; 45: 1715–1721.

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