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Original Article
356
Rev Bras Hematol Hemoter. 2012;34(5):356-60
Etiology of anemia of blood donor candidates deferred by hematologic screening
Introduction
There are several factors that lead to the deferral of candidates from donating blood
including anemia, in particular iron deficiency anemia which is strongly linked to the frequency
of donations
(1,2)
. In Brazilian blood banks, about 100,000 blood units are not collected annually
due to anemia; this significantly affects the blood stocks in the country
(3)
. This has also been
reported in other countries. A recent multicenter study carried out in several American states
reported alarming levels of iron deficiency among repeat donors; two thirds (66%) of women
and almost half (49%) of men were iron deficient
(4)
.
Besides iron-deficiency anemia, hemoglobinopathies are common in blood donors and
so the early detection of these blood disorders benefits both donors and recipients of blood
products. Donors will benefit by the prompt correction of iron deficiency and proper guidance
about the disease and recipients by receiving good quality blood
(1,2,5-8)
.
In several countries of the world, including Brazil, screening for anemia is essential for
blood donation and for the subsequent protection of the donor. Hemoglobin levels should be
above 12.5 g/dL and 13.0 g/dL and hematocrit concentrations above 38% and 39% in women
and men, respectively
(9,10)
.
The most frequently used technique to screen blood donors is a manual measurement of
hemoglobin or hematocrit of a blood sample obtained by finger prick
(1)
. The copper sulfate method
has also been used in some countries, although there are still doubts about its sensitivity, specificity
and accuracy
(11)
. Although there is no consensus among blood banks about what is the best method,
the International Committee for Standardization in Hematology proposes the measurement of
hemoglobin by an automated technique using the cyanmethemoglobin method
(12)
.
Hematological screening of donors in the Uberaba Regional Blood Bank (HRU-MG)
was made in the period of this study by manually measuring hemoglobin using the
cyanmethemoglobin method (Bioclin kit®, Belo Horizonte, Brazil) in a sample taken from
the digital pulp. However, on the possibility of deferral, additional laboratory methods were
used for confirmation, investigation of the etiology and to provide guidance, which is done
with the individual’s transfer to an appropriate referral service.
In 2003, anemia occurred most often in candidates on their first attempt to donate and
this was the commonest reason for the clinical deferral of blood donors (4% according to
Michel Alves da Silva
1
Renata Andréia Volpe de Souza
2
Aline Meneses Carlos
2
Sheila Soares
2
Helio Moraes-Souza
2
Gilberto de Araujo Pereira
2
1
Universidade Federal de Minas Gerais -
UFMG, Belo Horizonte, MG, Brazil
2
Universidade Federal do Triângulo Mineiro -
UFTM, Uberaba, MG, Brazil
Conflict-of-interest disclosure:
The authors declare no competing financial
interest
Submitted: 4/4/2012
Accepted: 6/21/2012
Corresponding author:
Renata Andréia Volpe de Souza
Universidade Federal do Triângulo Mineiro
- UFMG
Av. Frei Paulino, 30 - Bairro Abadia
38025-180 Uberaba, MG, Brazil
Phone: 55 34 3318-5000
revolpesouza2010@hotmail.com
www.rbhh.org or www.scielo.br/rbhh
DOI: 10.5581/1516-8484.20120092
Objective:
Iron deficiency is the most common cause of anemia and one of the main factors in the clinical
deferral of blood donors. This fact prompted the current study that aimed to determine the prevalence and
etiology of anemia in blood donor candidates and to evaluate the hematological screening technique used for
the exclusion of these donors.
Methods:
This was a prospective study that compared two groups (Anemic and Non-anemic). Initially screening
for anemia was performed by manually measuring hemoglobin (Bioclin® Kit); the results were subsequently
compared with an automated screening method (Coulter T-890). The etiology was investigated by hemoglobin
electrophoresis in alkaline and acid pH, Hb A2 dosage and measurement of the ferritin concentration by
immunoagglutination. Differences and associations of interest were analyzed using the Yates and McNemar’s
Chi-square tests and the Fisher, Mann-Whitney, Wilcoxon and Kruskal-Wallis tests.
Results:
The deferral rate due to anemia was 4.2%; iron deficiency was identified in 37.5% and beta thalassemia
in 9.3% of the excluded candidates. There was a significant discrepancy between the two techniques used
to measure hemoglobin with 38.1% of initially deferred donors presenting normal hemoglobin levels by the
automated method.
Conclusion:
The results show a high rate of blood donors being deferred for anemia and confirm that iron
deficiency is the most prevalent cause. The discrepancies found by comparing screening methods suggest
that hemoglobin and hematocrit levels should be confirmed before deferring a donor due to anemia; this may
increase supplies in blood banks.
Keywords:
Iron deficiency; Blood donors; Donor selection; Anemia