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Scientific Comments
Rev Bras Hematol Hemoter. 2012;34(5):323-33
Blood donation, blood supply, iron deficiency and anemia – It is time to shift attention
back to donor health
Since the 1980s blood collectors worldwide have focused on two central themes: blood
product safety and an adequate blood supply. From the standpoint of safety, specifically the
reduction of transfusion-transmitted diseases, the achievements over the past quarter century
are remarkable. With respect to the adequacy of the blood supply, the past decade has witnessed
major gains in some countries of Europe, Canada and the US and less than had been expected
in others, including Brazil, where the challenge of having a more stable blood supply, in which
supply and demand are in better balance remains an important issue
(1)
.
On the other hand, the aforementioned achievement has come at a price: iron depletion
of the repeat blood donor. Blood centers have long recognized that it is more effective and less
expensive to collect blood from existing donors than to recruit new donors. While first-time
donors, particularly the young and minorities, have been more successfully recruited, 70% of
US and 40-70% (depending on the region) of Brazilian donors are repeat donors
(1,2)
.
The only known significant disadvantage of blood donation is the potential risk of iron
deficiency (ID). Iron is a vitally important element in the human metabolism. It plays a central
role in erythropoiesis and is also involved in many other intracellular processes in all the
tissues of the body. The potentiality of the individual donor to give blood without developing
ID and iron deficiency anemia (IDA) varies widely, probably due to differences in nutritional
iron intake, the differences in prevalences of ID in each study population, menstrual iron loss
in females, the frequency of blood donation and the use of supplemental iron
(2)
.
The frequency of ID is high in blood donors (1.8% to 8.4% in males and 4.5% to 34.8%
in females), and more dependent on the frequency of donations than on the cumulated number
of donations
(2-4)
. In addition to this, ID is a significant problem and its prevalence is increasing
in many countries around the world. The prevalence has been reported to be 9-40% in women,
depending on age and menstrual status and 2-5% in men
(1,2)
. Because menstruating females
begin their blood donation careers from a lower starting point, subsequent donations pose a
risk for greater clinical harm. Females have much higher rates of both ID and IDA.
The clinical implications of ID and IDA are not insignificant, including fatigue, reduced
work performance and intellectual capacity, reduced endurance, restless leg syndrome, pica,
and cognitive and immune function changes. The degree of symptomatology is proportionate
to the severity of the anemia
(1,2)
.
Moreover, low hemoglobin (Hb) accounts for 4-10% of total deferrals, with the vast
majority occurring in women. Therefore it seems reasonable to secure adequate iron reserves
in the donor population in order to maintain an appropriate donation potentiality and to avoid
possible hematological and non-hematological complications related to ID
(1,2)
.
The question that arises is whether this practice is in the best interest of donor health. In
this issue of
Revista Brasileira de Hematologia e Hemoterapia
, Silva et al., representing the
Hemocentro Regional de Uberaba, Minas Gerais, Brazil, have brought this issue to light
(5)
.
Given the findings in this and other studies, what measures can blood collectors pursue
to address iron depletion? There is no single answer, but several approaches should be
considered: 1) modifying the donor Hb requirements and measurement of Hb, 2) changing the
interdonation interval, 3) testing for serum ferritin, and 4) iron supplementation.
1. Modifying donor Hb requirements and measurement of Hb
The current minimum Hb requirement in the Brazilian guidelines as well as in the
European Union guidelines is 12.5 g/dL for females and 13.0 g/dL for males; these values
seem to be reasonable
(6,7)
. However, we know that IDA is the last stage of ID and it is evident
that Hb measurement, alone, is inadequate to detect blood donors with ID but without anemia.
It is not surprising that the current practice results in accepting many iron-depleted female
donors who have normal Hb values
(2)
.
Regarding measurement of Hb, Silva et al. demonstrated that there was significant
discrepancy between the Hb measurements, with 38% previously considered unfit,
Rodolfo Delfini Cançado
Dante Langhi Junior
Faculdade de Ciências Médicas da Santa Casa
de São Paulo - FCMSCSP, São Paulo, SP, Brazil
Conflict-of-interest disclosure:
The authors declare no competing financial
interest
Submitted: 8/10/2011
Accepted: 8/11/2012
Corresponding author:
Rodolfo Delfini Cançado
Hemocentro da Santa Casa de São Paulo
Rua Marquês de Itú, 579 – 3º andar
01223-001 -São Paulo, SP, Brazil
Phone: 55 11 21767255
www.rbhh.org or www.scielo.br/rbhh
DOI: 10.5581/1516-8484.20120086