Print version ISSN 1516-8484
Rev. Bras. Hematol. Hemoter. vol.34 no.5 São Paulo 2012
Maria Stella Figueiredo
Universidade Federal de São Paulo - UNIFESP, São Paulo, SP, Brazil
The World Health Organization recommends a collection rate of 10-20 whole blood units per 1000 inhabitants to address transfusion needs(1). However, demand for blood is ever-increasing as medicine continuous to develop(2).
Donor selection is critical to blood transfusion safety and blood donor eligibility policies are designed to protect both the donor and the recipient(1,3). Donors with relatively low hemoglobin (Hb) levels are not allowed to donate to prevent them from developing iron deficiency anemia (IDA). In addition, deferral of these donors guarantees that blood units for transfusion meet the required standards for Hb content(4).
Deferral for low Hb accounts for 35% to 75% of total deferrals, with the vast majorityoccurring in women(5-7). At the New York Blood Center, 92.7% of these deferrals were women(6,7).
Iron deficiency is the world's most widespread nutritional disorder, affecting both industrialized and developing countries(8). In Brazil, there are no consistent studies to show the real problem, although some studies showed 25% of anemia in women of childbearing age(9,10).
On the other hand, because IDA is the last stage of iron-deficiency, Hb measurement alone is inadequate to detect blood donors with iron deficiency but without anemia. Recent publications have suggested that serum ferritin levels could be a reliable indicator for body iron stores since they provide a determination of iron deficiency at an early stage(11,12).
As ferritin testing is comparatively costly, various red blood cell (RBC) parameters have been proposed as markers for low ferritin/iron depletion(13). Significant correlations between ferritin and RBC parameters were shown in these analyses, but no study has determined which marker is the most useful to identify donors at risk of developing anemia(13).
Beta-thalassemia trait (BTT) is the second most common cause of microcytic anemia and, for this reason, the possibility of this disease must be discarded when anemia or microcytosis is present(12,14). An interesting paper by Tiwari et al.(14) suggested that it could be useful to routinely perform a complete blood count (CBC) for all blood donors and further analyze the microcytic samples for ferritin and Hemoglobin A2 to differentiate between IDA and BTT. This approach, however, is relevant only in areas where there is an elevated prevalence of BTT. These authors, also, reviewed nine indices to differentiate IDA and BTT. (Table 1)
In order to fulfill their necessities, blood centers have long recognized that it is more effective and less expensive to collect blood from existing donors than to recruit new donors and in the United States, 71% of donors are repeat donors. But, this strategy has come at a price: iron depletion of these donors(5). After donation of 450 mL of blood, a male donor loses 242 ± 17 mg and a female 217 ± 11 mg of iron(5,15). Since the 1970s, various investigators documented the decrease in serum ferritin levels in association with blood donation(5,11,13,16-18).
The lost iron is not readily repleted. It has been common practice for blood centers to recommend iron-rich diets to donors who have been rejected for low Hb. However, even with excellent compliance, it requires 6 months or longer to positively impact ferritin levels(5). Because of this, many researches have prescribed iron supplementation with good results(15,19,20). However, the majority of regular blood donors with low or absent iron stores will never develop IDA(13).
It is important to remember that avoiding unnecessary deferrals, keeps donors engaged with the blood center(6). In fact, Boulton demonstrated that only 25% of first-time donors return to the blood donation facility after rejection, while 47% of first-time donors come back within 6 months when accepted at their first visit(21).
Anemia is an important topic for blood donor candidates and effort has to be made to identify these individuals, prevent iron depletion in regular blood donors, and engage these individuals with blood donation.
1. Kouao MD, Dembele B, N'Goran LK, Konate S, Bloch E, Murphy EL, et al. Reasons for blood donation deferral in sub-Saharan Africa: experience in Ivory Coast. Transfusion. 2012;52(7 Pt 2):1602-6. [ Links ]
2. Bonig H, Schmidt M, Hourfar K, Schuttrumpf J, Seifried E. Sufficient blood, safe blood: can we have both? BMC Med. 2012;10:29. [ Links ]
3. Gonçalez TT, Sabino EC, Schlumpf KS, Wright DJ, Mendrone A, Lopes M 1st, Leão S, Miranda C, Capuani L, Carneiro-Proitetti AB, Basques F, Ferreira JE, Busch M, Custer B; NHLBI Retrovirus Epidemiology Donor Study-II (REDS-II), International Component. Analysis of donor deferral at three blood centers in Brazil. Transfusion. 2012. Doi: 10.1111/j.1537-2995.2012.03820.x. [ Links ]
4. Baart AM, de Kort WL, Atsma F, Moons KG, Vergouwe Y. Development and validation of a prediction model for low hemoglobin deferral in a large cohort of whole blood donors. Transfusion. 2012. Doi: 10.1111/1537-2995.2012.03655.x. [ Links ]
5. Popovsky MA. Anemia, iron depletion, and the blood donor: it's time to work on the donor's behalf. Transfusion. 2012;52(4):688-92. [ Links ]
6. Davey RJ. Recruiting blood donors: challenges and opportunities. Transfusion. 2004;44(4):597-600. [ Links ]
7. Bianco C, Brittenham G, Gilcher RO, Gordeuk VR, Kushner JP, Sayers M, et al. Maintaining iron balance in women blood donors of childbearing age: summary of a workshop. Transfusion. 2002;42(6):798-805. [ Links ]
8. WHO. Nutrition for Health and Development. A global agenda for combating malnutrition: World Health Organization; 2000. [ Links ]
9. Batista Filho M, de Souza AI, Bresani CC. Anemia como problema de saude publica: uma realidade atual. Cienc Saude Coletiva. 2008;13(6):1917-22. [ Links ]
10. Brasil. Ministério da Saude. Pesquisa Nacional de Demografia e Saúde da Criança e da Mulher. PNDS, 2006. Brasília, DF. 2009. Available from: http://bvsms.saude.gov.br/bvs/folder/pesquisa_demografia_saude_crianca_mulher2006.pdf [ Links ]
11. Cancado RD, Chiattone CS, Alonso FF, Langhi Junior DM, Alves Rde C. Iron deficiency in blood donors. Sao Paulo Med J. 2001;119(4):132-4; discussion 131. [ Links ]
12. Silva MA, de Souza RA, Carlos AM, Soares S, Moraes-Souza H, Pereira GA. Etiology of anemia of blood donor candidates deferred by hematologic screening. Rev Bras Hematol Hemoter. 2012;34(5): 356-60 [ Links ]
13. Stern M, O'Meara A, Infanti L, Sigle JP, Buser A. Prognostic value of red blood cell parameters and ferritin in predicting deferral due to low hemoglobin in whole blood donors. Ann Hematol. 2012;91(5):775-80. [ Links ]
15. Mahida VI, Bhatti A, Gupte SC. Iron status of regular voluntary blood donors. Asian journal of transfusion science. 2008;2(1):9-12. [ Links ]
16. Cable RG, Glynn SA, Kiss JE, Mast AE, Steele WR, Murphy EL, Wright DJ, Sacher RA, Gottschall JL, Tobler LH, Simon TL, Nemo GJ, Schulman J, King MR, Busch MP, Norris P, Rios JA, Benjamin RJ, Roback JD, Wilkinson SL, Carey PM , Custer BS, Hirschler NV, Triulzi DJ, Kakaiya RM, Mast AE; NHLBI Retrovirus Epidemiology Donor Study-II (REDS-II). Iron deficiency in blood donors: the REDS-II Donor Iron Status Evaluation (RISE) study. Transfusion. 2012;52(4):702-11. [ Links ] Comment in: Transfusion. 2012;52(6):1382-3; author reply 1383-5. [ Links ]
17. O'Meara A, Infanti L, Stebler C, Ruesch M, Sigle JP, Stern M, et al. The value of routine ferritin measurement in blood donors. Transfusion. 2011;51(10):2183-8. [ Links ]
18. Passos LN, Yurtserver MS, Silva UG, Cordeiro GW, Machado LF, Vasques F, et al. Sideropenia sem anemia em doadores de sangue do Hemocentro do Amazonas - Hemoam. Rev Bras Hematol Hemoter. 2005;27(1):48-52. [ Links ]
19. Radtke H, Mayer B, Rocker L, Salama A, Kiesewetter H. Iron supplementation and 2-unit red blood cell apheresis: a randomized, double-blind, placebo-controlled study. Transfusion. 2004;44(10):1463-7. [ Links ]
20. Radtke H, Tegtmeier J, Rocker L, Salama A, Kiesewetter H. Daily doses of 20 mg of elemental iron compensate for iron loss in regular blood donors: a randomized, double-blind, placebo-controlled study. Transfusion. 2004;44(10):1427-32. [ Links ]
21. Boulton F. Evidence-based criteria for the care and selection of blood donors, with some comments on the relationship to blood supply, and emphasis on the management of donation-induced iron depletion. Transfus Med. 2008;18(1):13-27. [ Links ]
Maria Stella Figueiredo
Disciplina de Hematologia e Hemoterapia - Escola Paulista de Medicina - UNIFESP
Rua Dr Diogo de Faria, 824, 3º andar Vila Clementino
04037-002 -São Paulo, SP, Brazil
Conflict-of-interest disclosure: The author declares no competing financial interest