Prevalence of hemoglobin S trait among blood donors: a cross-sectional study
Antwi‑Baffour et al. BMC Res Notes
Prevalence of hemoglobin S trait among blood donors: a cross‑sectional study
Samuel Antwi‑Baffour s.antwi‑ 0
Ransford Owiredu Asare 0
Jonathan Kofi Adjei 0
Ransford Kyeremeh 0
David Nana Adjei 0
0 Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, College of Health Sciences, University of Ghana , P. O. Box KB 143, Korle‐Bu, Accra , Ghana
Background: Sickle cell trait (SCT) or Hemoglobin S (HbS) trait which is due to inheritance of an abnormal hemoglobin (Hb) gene from one parent and a normal gene from the other has been known to be common among people of African descent. Individuals with SCT may find themselves in the blood donor population without knowing their 'carrier' status and this may have severe consequences on their health as well as that of a recipient, particularly if they happen to be a sickle cell disease patient. The aim of the study was to determine the prevalence of HbS trait among blood donors. Results: This cross‑ sectional study employed convenience sampling method to recruit subjects. A total of 150 prospective and healthy blood donors comprising 138 males and 12 females were involved in the study. Two (2) ml of venous blood was collected from each donor into K3EDTA tubes and analyzed using the sodium metabisulphite slide test and cellulose acetate Hb electrophoresis at alkaline pH (8.6) for Hb genotypes. Statistical Package for Social Sciences version 20.0 (SPSS 20.0) and Chi square were used to analyse the data obtained. Out of the 150 blood donors, 133 (88.7 %) tested negative for sickling (131 were genotype AA and 2 were AC) and 17 (11.3 %) tested positive for sickling, all of whom were genotype AS. Conclusion: The results of the study showed the existence of SCT among the blood donor population sampled. Taking blood from such people can harm their health as well as that of the recipient if they happen to be sickle cell disease (SCD) patients. It is therefore recommended that blood donors as well as donated blood units should be screened for SCT to avoid causing any harm to both the donor and recipient.
Hemoglobin; Blood donor; Sickle cell disease; Electrophoresis; Genotype
Sickle cell disease (SCD) refers to a group of disorders
that affects hemoglobin (Hb), causing them to form
abnormal hemoglobin S (HbS) molecules [
people inherited the abnormal gene (HbS) from both
parents. A person who inherits an abnormal gene from one
parent and a normal gene from the other has a sickle cell
trait (SCT) or is said to be a carrier of SCD [
]. The gene
for sickle cell disease is more common in Sub-Sahara
Africa, Mediterranean countries, the Middle East and
]. The Hispanic population of both Spanish or
Latin American descent is also at risk of the disease—at
least 1 in 180 Hispanic births have sickle cell trait [
Reports from studies conducted in Ghana show that
about 25–30 % of the Ghanaian population carry the
sickle cell trait and 2 % of newborns have sickle cell
]. Sickle cell disease is a major public health
concern, having socio-economic implications for the affected
child as well as their family. Patients with SCD are often
hospitalised for long periods [
]. Also, death in early
childhood as a result of SCD is high in Africa partly due
to lack of comprehensive healthcare [
Blood transfusion is an important act that saves
millions of lives each year [
]. It is estimated that over 90
million blood units are collected worldwide each year
]. According to the WHO, four main types of blood
donors can be identified. They include: voluntary
nonremunerated donors; family/replacement/directed
donors; paid/commercial donors and autologous donors
]. In order to ensure a safe and sufficient blood
supply, the WHO adopted a strategy that aimed to
implement a national policy for each African country by 2012
]. This included the recruitment of regular voluntary,
healthy and non-remunerated blood donors. However,
with the high prevalence (25–30 %) of sickle cell trait in
Ghana, people who have the sickle cell trait may enrol
as prospective blood donors since majority of them are
asymptomatic and in stable condition [
may therefore find themselves in the donor population
unknowingly. This may have severe consequences on
their health after they have donated blood as well as that
of the recipients particularly if they happen to have sickle
Patients with SCD may require frequent blood
transfusion to treat complications associated with the disease
]. However, transfusing blood containing HbS to
a SCD patient can increase the proportion of sickled red
cells in the person’s circulation, inducing further sickling
and causing occlusions in the microcirculation . This
deprives the tissues and organs of oxygen, resulting in
vaso-occlusive crisis and affecting proper management of
the patient [
]. In view of the above, this study sought
to determine the prevalence of HbS trait among blood
donors to help in ensuring efficient and safe blood
donation and transfusion.
The study was a cross-sectional study carried out from
May to July, 2014.
The study subjects were apparently healthy individuals
between the ages of 17 and 60 years who came to donate
blood at the southern area blood centre (SABC) of the
Korle-bu Teaching Hospital, Accra. They included
voluntary and replacement blood donors.
Ethical clearance for this research was sought from the
Ethics and Protocol Review Committee at the School
of Biomedical and Allied Health Sciences, University of
Ghana, Legon. All the participants gave their informed
consent before their samples were collected.
Some of the materials needed for the work include: EDTA
tubes, 2 % Sodium metabisulphite, Physiological saline
(0.85 %), Electrophoretic tank and power pack (Consort
EV 243), Centrifuge, Cellulose acetate paper/membrane,
Tris–EDTA Borate (TEB) buffer (pH 8.6), Carbon
tetrachloride (CCl4), 5 % Acetic acid, Ponceau S stain.
One hundred and fifty (150) subjects, involving 138
males and 12 females were recruited using convenience
sampling method. Two millilitres (2 ml) of blood was
collected from each of the participants during blood
donation into labelled tri-potassium ethylene diamine
tetra-acetic acid (K3EDTA) tubes and mixed gently. All
samples were kept at 4–8 °C after which they were
transported to the laboratory for analysis. Samples were
processed within 24 h after collection.
Sickling test (Sodium metabisulphite method)
Equal volumes of well-mixed EDTA anticoagulated blood
and 2 % sodium metabisulphite were mixed on a cleaned
labelled slide, covered with a cover slip and incubated at
room temperature for at least 30 min. It was then
examined microscopically, using the 40× objective for sickle
cells. Sickle cells appeared crescent-shaped [
and negative controls, from a known sickle cell trait
person and a person without the sickle cell trait respectively,
were set-up alongside the test.
Hemoglobin electrophoresis (cellulose acetate method at alkaline pH)
The blood samples were centrifuged at 1500g for 5 min
and the plasma removed. The red cells were then washed
four times with physiological saline (0.85 %). Few drops
of distilled water were added to lyse the cells after which
four drops of CCl4 was added, vortexed and centrifuged
at 1500g for 20 min to separate the hemoglobin. The
Hemolysate was transferred into a clean glass test tube
Each compartment of the electrophoretic tank was
filled with Tris–EDTA Borate (TEB) buffer (pH 8.6) to a
depth of about 2.5 cm. The cellulose acetate membrane
was impregnated with TEB buffer and blotted with a
tissue paper to remove excess buffer, but not allowed
to dry. By means of an applicator, the control and test
hemolysate samples were applied on the cellulose acetate
membrane and carefully introduced onto the frame of the
electrophoretic tank, with both ends in contact with the
buffer. The lid of the tank was replaced and the tank
connected to a power supply of voltage 250 V and current
50 mA, and allowed to run for 30 min. The power was
disconnected and the membrane removed and stained
with Ponceau S for 5 min. The excess stain was removed
with 3 changes of 3 % acetic acid for 5 min each. The
membrane was blotted and allowed to air-dry after which
it was labelled and the results read against the controls
]. A combination of hemolysate from a sickle cell trait
(AS) and HbC trait samples (ASC) served as the control.
Data collected was entered into Microsoft Office Excel
2010 and analysed using Statistical Package for Social
Sciences version 20.0 (SPSS 20.0). A summary was
presented using descriptive statistics such as frequencies,
percentages, mean and standard deviations. Chi square
analysis was used to establish association between
sickling status, Hb genotypes and gender. A p value of <0.05
was considered statistically significant.
A total number of 1300 prospective and mainly
replacement blood donors presented to donate blood during the
period of this study. Out of these, 1066 (82 %) were males
and 234 (18 %) females. The study examined one
hundred and fifty (150) of these donors who consented to take
part in the study. Out of these, 138 (92 %) were males and
12 (8 %) females respectively. The mean age of the
participants was 30.5 ± 8.4 years. The youngest participant
was 18 years and the oldest was 51 years. The age group
of 20–24 was the highest representing 28.7 % of the total
number of participants (Table 1). Only four (4) participants
(first time donors) representing 2.7 % knew their sickling
status and Hb genotype while the remaining 146 (97.3 %)
did not know both their sickling status and Hb genotypes.
Ninety-six (64 %) of them had not donated blood before
but the remaining 54 (36 %) had (Table 1). Out of the 54
that have had previous blood donation experience, 29 had
donated blood once, 14 twice, 7 thrice and 4 four times. In
terms of types of donors, Sixteen (16) participants
representing 10.7 % were voluntary donors and the remaining
134 representing 89.3 % were replacement donors. There
were no commercial and autologous donors.
For the sickling status of the participants, seventeen
(17) representing 11.3 % tested positive for sickling
(Fig. 1a) while the remaining 133 (88.7 %) were sickling
negative (Fig. 1b) as shown in Table 2. Twelve (8.7 %) of
the 138 male participants tested positive for sickling with
the remaining 126 (91.3 %) testing negative. Also, out of
12 females, 5 (41.7 %) tested positive for sickling and 7
(58.3 %) were sickling negative as shown in Table 2 below.
Out of the total 150 donors, 131 (87.3 %), 2 (1.3 %) and 17
(11.3 %) were AA, AC and AS respectively. Subsequently,
124 (89.9 %) of the males were AA, 2 (1.4 %) were AC and
12 (8.7 %) were AS, then 7 (58.3 %) of the females were
AA and 5 (41.7 %) were AS with no AC (Fig. 2) (Table 2).
Discussion and conclusion
Blood transfusion is a therapeutic procedure but can be
harmful instead of saving lives. Every blood donation and
transfusion carries a potential risk for both the donor
and recipient [
]. Individuals with certain medical
defects may unknowingly find themselves in the donor
population which may have effect on their health as well
as that of the recipient . The Blood Transfusion
Services therefore, have a duty of care towards blood donors
and recipients to make sure any contraindications are
Out of the total 150 blood donors involved in this
study, 138 (92 %) were males and 12 (8 %) were females
giving a male to female ratio of 12:1. This was high
compared to the gender distribution in another study that
had a male to female ratio of 4:1 from a population of
]. The greater proportion of male donors
compared to females in our study may be attributed
to the fact that females are not very much encouraged
to participate in blood donations, be it voluntary or
replacement due to certain socio-cultural beliefs. Other
physiological conditions may also exclude females from
blood donation including pregnancy, lactation and
menstruation . Age distribution also showed that,
the age group of 20–24 years had the highest number
of blood donors (28.7 %) which is similar to the
findings in a study by Omisakin et al. that had age group of
15–24 years (53.8 %) with the highest number of donors
Only 4 (2.7 %) of the participants had knowledge of
their sickle cell status and Hb genotype, which agrees
with a study by Lippi et al. that stated that most blood
donors, especially those with SCT are not aware of their
sickle cell status [
]. This is because individuals with
SCT are usually asymptomatic with most of their
hematological parameters such as hemoglobin and red blood
cell indices within the normal range [
]. Those with
the knowledge of their sickling status were first time
donors and presented themselves for donation because
they were not aware their sickling status had any
bearing on them as blood donors. The prevalence of SCT—
(AS) of 11.3 % in this study was found to be lower than
the 25–30 % quoted for Ghana and 20–40 % for Africa in
]. Also, considered low in relation to studies
done by Omisakin et al. and Zaccheaus et al. which had
prevalence of HbS trait as 26.1 and 19.68 % respectively
It is recommended that, to achieve a safe and
sufficient blood supply, blood should be collected from
voluntary non-remunerated donors who have a lower
risk of Transfusion-transmissible infections (TTIs)
compared to replacement and commercial donors [
However, in this study, only 10.7 % were voluntary
donors compared to 89.3 % of replacement donors. This
falls short of the 80–100 % voluntary donations
encouraged in a publication by the centre for disease control of
the WHO [
There is significant number of people carrying sickle
cell trait, especially in Africa and Ghana in particular,
who might not be aware of their carrier status before
enrolling to be blood donors. It is therefore reasonable
to consider the possibility of implementing a practice
of routine screening for sickle cell trait in blood donors
prior to donating blood or donated blood units. This way
transfusion of HbS containing blood to recipients, which
can induce further sickling in sickle cell patients, may
be avoided. This will go a long way to help in the proper
management of sickle cell disease patients and to
establish a useful diagnosis of SCT in blood donors.
CCl4: carbon tetrachloride; EDTA: ethylene diamine tetra‑acetic acid; Hb:
hemoglobin; HbA: hemoglobin A gene; HbAS: hemoglobin AS (SCT); HbC:
hemoglobin C gene; HbS: hemoglobin S gene; pH: hydrogen ion concentra‑
tion; SCD: sickle cell disease; SCT: sickle cell trait; SPSS: statistical package for
social sciences; TEB: tris‑EDTA borate buffer; TTIs: transfusion‑transmissible
infections; WHO: World Health Organization.
SAB participated in the design of the study, supervised the research and
drafted the manuscript. ROA participated in the design of the study and car‑
ried out the experimental work. JKA, RK and DNA participated equally in the
supervision of the work and proof reading of the manuscript. All authors read
and approved the final manuscript.
We are grateful to Prof. Patrick F. Ayeh‑Kumi the Dean of the School of
Biomedical and Allied Health Sciences (SBAHS), College of Health Sciences,
University of Ghana for his assistance in the development and drafting of the
manuscript. We will also like to acknowledge the following persons for their
help in putting the manuscript together: Dr. I.A Bello and Dr. Charles Brown of
The authors declare that they have no competing interests.
1. de Montalembert M. Management of sickle cell disease . Br Med J. 2008 ; 8 : 337 .
2. Chowing JT . Sickle cell anaemia case study: Summary . Biolab, Seatle, WA. 2000 . http://genetics‑ educationpartnership.mbt.washington.edu/download/sicklecell.pdf. Accessed June 2014 .
3. Michlitsch J , Azimi M , Hoppe C , Walters MC , Lubin B , Lorey F , Vichinsky E. Newborn screening for haemoglobinopathies in California . Pediatr Blood Cancer . 2009 ; 52 ( 4 ): 486 - 90 .
4. Fleming AF . The presentation, management and prevention of crisis in sickle cell disease in Africa . Blood Rev . 1989 ; 3 ( 1 ): 18 - 28 .
5. Makani J , Williams TN , Marsh K. Sickle cell disease in Africa: burden and research priorities . Ann Trop Med Parasitol . 2007 ; 101 ( 1 ): 3 - 14 .
6. World Health Organisation 2008 . Management of haemoglobin disorders . In: Proceedings of the Report of Joint WHO‑ TIF Meeting , Nicosia, Cyprus. November 2007 .
7. Ohene‑Frimpong K , Oduro J , Tetteh H , Nkrumah F . Screening newborns for sickle cell disease in Ghana . Paediatrics. 2008 ; 121 ( suppl 2 ): S120 - 1 .
8. Powars DR , Chan LS , Hiti A , Ramicone E , Johnson C. Outcome of sickle cell anaemia: a 4‑ decade observational study of 1056 patients . Medicine (Baltimore) . 2005 ; 84 ( 6 ): 363 - 76 .
9. Ghana Health Service. Non‑ communicable Disease Control Programme. Disease Control and Prevention Department . Strategic framework for the management, prevention and control of sickle cell disease in Ghana . 2010 .
10. Grosse SD , Odame I , Atrash HK , Amendah DD , Piel FB , Williams TN . Sickle cell disease in Africa: a neglected cause of early childhood mortality . Am J Prev Med . 2011 ; 41 ( 6 Suppl 4 ): S398 - 405 .
11. Noubiap JJN , Joko WY , Nansseu JRN , Tene UG , Siaka C . Sero‑ epidemiology of human immunodeficiency virus, hepatitis B and C viruses, and syphilis infections among first‑time blood donors in Edea, Cameroon . Int J Infect Dis . 2013 ; 17 ( 10 ): 832 - 7 .
12. World Health Organization 2008 -2015 . Universal access to safe blood transfusion , Geneva . 2007 .
13. World Health Organization. Blood donor selection. Guidelines on assessing donor suitability for blood donation . Annex 3 , Geneva . 2012 .
14. World Health Organization, Regional Office for Africa. Blood safety; a strategy for the African region . AFR/RCSI/R2; Brazzavile. 2001 .
15. World Health Organization. Sickle cell anaemia: report by the secretariat , 59th World Health Assembly. Provisional agenda item 11 .4; A59 /9. 2006 .
16. Omisakin CT , Esan AJ , Ogunleye AA , Ojo‑Bola O , Owoseni MF , Omoniyi DP . Glucose‑6 ‑phosphate dehydrogenase (G6PD) deficiency and sickle cell trait among blood donors in Nigeria . Am J Public Health Res . 2014 ; 2 ( 2 ): 51 - 5 .
17. Carson JL , Grossman BJ , Kleinman S , Tinmouth AT , Marques MB , Fung MK , et al. Red blood cell transfusion: a clinical practice guideline from the AABB . Ann Intern Med . 2012 ; 157 ( 1 ): 49 - 58 .
18. Wang WC . Sickle cell anaemia and other sickling syndromes' . In: Wintrobes clinical haematology, 12th edn. Philadelphia: Lippincott Williams and Wilkins . 2009 . pp. 1038 - 1082 .
19. Thurston GB , Henderson NM , Jeng M. Effects of erythrocytapheresis transfusion on the viscosity of sickle cell blood . Clin Hemorheol Microcirc . 2004 ; 30 ( 1 ): 61 - 75 .
20. Tsaras G , Owusu‑Ansah A , Boateng FO , Amoateng‑Adjepong Y . Complications associated with sickle cell trait: a brief narrative review . Am J Med . 2009 ; 122 ( 6 ): 507 - 12 .
21. Cheesbrough M ( 2006 ) Haematological tests: abnormal haemoglobins . In: District laboratory practice in tropical countries . Part 2 , 2nd ed. Cambridge Universal Press, New York, pp 283 - 340
22. Dacie JV , Lewis SM ( 2012 ) Investigation of abnormal haemoglobin and thalassemia . In: Practical haematology. 11th ed. Elsevier , pp 310 - 312
23. Bhawani Y , Rao PR , Sudhakar V . Seroprevalence of transfusion transmissible infections among blood donors in a tertiary care hospital of Andhra Pradesh . Biol Med . 2010 ; 2 ( 4 ): 45 - 8 .
24. Khan S , Attaullah S , Ayaz S , Niaz Khan S , Shams S , Ali I , et al. Molecular epidemiology of HCV among the health care workers of Khyber Pakhtunkhwa . Virol J . 2011 ; 8 ( 1 ): 105 . doi: 10 .1186/ 1743 ‑422X ‑ 8 ‑105.
25. Cheesbrough M. Blood transfusion practice: blood donation and storage of blood, district laboratory practice in tropical countries, low‑price editions by Cambridge Universal Press. Part. 2002 ; 2 : 352 - 3 .
26. Lippi G , Mercandanti M , Caleffi A , Franchinii M. An unusual case of a spurious transfusion‑acquired haemoglobin S . Blood Transfusion . 2010 ; 8 ( 3 ): 199 - 202 .
27. Schilirò G , Comisi FF , Testa R , Dibenedetto SP , Samperi P , Marino S. Haematological findings in 375 Sicilians with HbS trait . Haematologica . 1990 ; 75 ( 2 ): 113 .
28. Zaccheaus AJ . Abnormal haemoglobin variants, ABO and Rh blood groups among students of African descent in Port Harcourt, Nigeria . J Afr Health Sci . 2006 ; 6 ( 3 ): 177 - 81 .
29. World Health Organization/ Centre for Disease Control . Inter‑regional workshop on 'blood donor selection and donor counselling' for priority countries in the African and Eastern Mediterranean Region . Nairobi: Kenya; 2011 . p. 29 - 30 .