Content uploaded by Osaro Erhabor
Author content
All content in this area was uploaded by Osaro Erhabor
Content may be subject to copyright.
e-ISSN: 2319-9865
p-ISSN: 2322-0104
RRJMHS | Volume 2 | Issue 4 | October-December, 2013 58
Research and Reviews: Journal of Medical and Health Sciences
The Distribution of ABO and Rhesus Blood Groups among Residents of Gusau,
Zamfara State, North Western Nigeria.
Erhabor O1, Isaac IZ1, Saidu A1, Ahmed HM1, Abdulrahaman Y1, Festus A2, Ikhuenbor DB2,
Iwueke IP3, and Adias TC4.
1Department of Haematology, Faculty of Medical Laboratory Science Usmanu Danfodio University Sokoto, Nigeria.
2Usmanu Danfodio University Teaching Hospital Sokoto, Nigeria.
3Pathology Department, Federal Neuro Psychiatric Hospital Kware, Sokoto, Nigeria.
4 College of Health Technology Bayelsa State, Nigeria.
Research Article
Received: 23/08/2013
Revised: 26/08/2013
Accepted: 11/09/2013
*For Correspondence
Department of Haematology,
Faculty of Medical Laboratory
Science Usmanu Danfodio
University Sokoto, Nigeria.
Keywords: ABO, Rhesus, Blood
groups, Gusau, Zamfara State,
Nigeria.
ABSTRACT
The prevalence of ABO and Rhesus blood groups varies from race
to race. The study was designed to determine the distribution of ABO and
Rhesus (Rh) blood group among residents of Gusau, Zamfara State in
North Western, Nigeria. ABO and Rhesus phenotyping was carried out
using standard tube techniques using Biorad Seraclone anti-A, anti-B,
anti-AB and anti-D reagents (Bio Rad Medical Diagnostics, Germany). Of
the 500 subjects screened, 227(55.4%) were of blood group O,
119(23.8%) were blood group B, 88(17.6%) group A and 16(3.2%) group
AB. Of the 500 subjects tested, 494 (98.8%) were Rh D positive while
6(1.2%) were Rh D negative. The distribution of ABO blood groups were
compared based on gender. Prevalence of ABO blood group was
significantly higher among male donors (12.6%, 12.8, 2.0 and 45.4)
compared to (5.2%, 11.8, 1.2 and 10.0%) for female donors respectively
for ABO blood group A, B, AB and O. Similarly Rhesus blood group
distribution was compared based on gender. Men had a higher
prevalence of Rh positive and negative groups compared to female
(26.20% and 0.40%) versus (72.60% and 0.80%) respectively. The
pattern of distribution of ABO blood groups among Gausa residents
appeared to be at variant with other populations in Nigeria and other
countries. Evidence –based data obtained in this study will facilitate the
optimum stocking of blood and blood products in Blood banks in the area
as well as facilitate the formulation on relevant transfusion policies.
INTRODUCTION
The human red blood cell (RBC) membrane is complex and contains a significant number of blood group
antigens, the most clinically significant being the ABO and the Rhesus antigens. The ABO blood group system is
based on the presence of antigens A and B. Four major groups (A, B, AB and O) exist based on the presence of
these antigens either singly (A, B), doubling (AB) or absence of both antigen (O). Individuals who have the antigens
A and B on their red cells lack the group specific agglutinins in the serum [1, 2, 3]. The major determinant of the
Rhesus blood group is the D antigen. Individuals who have the D antigen on their red cells are known as known as
Rhesus positive while those without antigen D in their RBC’s are Rhesus negative [4]. The clinical significance of the
ABO and Rh blood group system depends on the ability of agglutinins of both blood group systems to cause
haemolytic transfusion reaction and haemolytic disease of the foetus and newborn (HDFN) [5,6,7].The prevalence of
ABO and Rhesus blood groups varies from race to race. The type and stock levels of blood and blood products
available in the hospital blood bank in any community should ideally closely correlate with the distribution of the
clinically significant red cell antigens in the general population. Although the prevalence of the ABO and Rhesus
blood has been reported in some ethnic groups in Nigeria [8,9,10], none has been carried out in Gusau in North
Western Nigeria. Knowledge of the distribution of the various blood groups is also important in the formulation of
relevant blood transfusion policies. Nigeria is the most populous country in Africa and accounts for approximately
one-sixth of Africa’s people. The country is diverse and has 389 ethnic groups. This aim of this present study was to
e-ISSN: 2319-9865
p-ISSN: 2322-0104
RRJMHS | Volume 2 | Issue 4 | October-December, 2013 59
determine the prevalence of ABO and RhD blood group among 500 consecutively recruited subjects of African
descent resident in Gusau, Zamfara State in the North West geopolitical zone of Nigeria.
MATERIALS AND METHODS
Study Population
This prospective case study was carried out in the Faculty of Medical Laboratory Science in Usmanu
Danfodiyo University in Sokoto, North Western Nigeria. All the participants gave their written, informed consent and
were offered pre- and post-test counseling. Ethical approval was obtained from the ethical committee in the Faculty.
The aim of this present study was to investigate the prevalence ABO blood and Rh blood groups among 500
consecutively recruited subjects of African descent resident in Gusau, Zamfara State in the North West geopolitical
zone of Nigeria.
Study Area
Gusau is a city and local government area located in Northwestern Nigeria. It is the capital of Zamfara
State. The LGA has an area of 3,364 km² and a population of 383,162 at the 2006 census. Its population is mostly
Hausa with some Fulani, Yoruba and Igbo.
Sample collection and methods
Blood samples were collected by venipuncture into ethylene diamine tetracetic acid (EDTA) anticoagulated
tubes and used for the determination of ABO blood and Rh blood groups among 500 consecutively recruited
subjects. Red cell phenotyping was carried out using standard tube techniques as described by Judd [11] and
Brecher [12]. For ABO blood grouping, a drop of Biorad Seraclone anti-A, anti-B, and anti-AB (Bio Rad Medical
Diagnostics, Germany) each was placed in clean test tubes labelled 1, 2, and 3. To each tube was added a drop of
5% red blood cell suspension in saline. The contents were gently mixed together and centrifuged for 30 seconds at
1000g. The cell buttons were re-suspended and observed for agglutination. Agglutination of tested red cells
constituted positive results and indicates that the red cells contain the group specific antigens. A smooth cell
suspension after re-suspension followed by a microscopic confirmation constituted negative test results. For
Rhesus D typing, a drop of Seraclone anti-D (RH1) blend serum (Bio Rad Medical Diagnostics, Germany) was placed
in a clean labelled test tube and a drop of control placed in a second tube. 1 drop of 5% RBC suspension in saline
was then added and incubated at 37°C. At the end of the incubation period, the contents of the tube were mixed
gently and centrifuged for 30 seconds at 1000g. Agglutination was read macroscopically and microscopically. All
negative results were confirmed using the indirect antiglobulin test (IAT) procedure (also for confirmation of weak
D).
OBSERVATIONS AND RESULTS
Of the 500 subjects screened, 227(55.4%) were of blood group O, 119(23.8%) were blood group B,
88(17.6%) group A and 16(3.2%) were group AB. Table 1 show the percentage distribution of ABO blood groups in
Gusau metropolis. Of the 500 subjects tested, 494 (98.8%) were Rh D positive while 6(1.2%) were Rh D negative.
Table 2 show the percentage distribution of Rh blood groups. The distribution of ABO blood groups were compared
based on gender. Prevalence of ABO blood group was significantly higher among male donors (12.6%, 12.8, 2.0
and 45.4) compared to (5.2%, 11.8, 1.2 and 10.0%) for female donors respectively for ABO blood group A, B, AB
and O. Table 3 show the percentage of ABO blood groups in Gusau metropolis based on gender. Similarly Rhesus
blood group distribution was compared based on gender. Men had a higher prevalence of Rh positive and negative
groups compared to female (26.20% and 0.40%) versus (72.60% and 0.80%) respectively. Table 4 show the
percentage of Rh blood groups in Gusau metropolis based on gender.
Table 1: Percentage distribution of ABO blood groups in Gusau metropolis
ABO Blood
Group
Number (%)
A
88(17.60%)
B
119(23.80%)
AB
16(3.20%)
O
277(55.40%)
Total
500 (100%)
e-ISSN: 2319-9865
p-ISSN: 2322-0104
RRJMHS | Volume 2 | Issue 4 | October-December, 2013 60
Table 2: Percentage distribution of Rhesus blood groups in Gusau metropolis
Rhesus Group
Number (%)
Rh Positive
494
(98.80%)
Rh Negative
6(1.20%)
Total
500(100%)
Table 3: Percentage of ABO blood groups in Gusau metropolis based on gender
ABO Blood Group
Gender
Total
Male Number
(%)
Female Number
(%)
A
62 (12.60%)
26 (5.20%)
88 (17.60%)
B
64 (12.80%)
55 (11.80%)
119 (23.80%)
AB
10 (2.00%)
6 (1.20%)
16 (3.20%)
O
227 (45.40%)
50 (10.00%)
277 (55.40%)
Total
363 (72.80%)
137 (21.20%)
500 (100%)
Table 4: percentage of Rh blood groups in Gusau metropolis based on gender
Rhesus (Rh)
Blood Group
Gender
Male Number
(%)
Female Number
(%)
Rh positive
363(72.60%)
131(26.20%)
Rh negative
4(0.80%)
2(0.40%)
Total
367(73.40%)
133(26.60%)
DISCUSSION
The ABO blood group system is one of the most clinically significant blood group systems because of the
regular occurrence of antibodies of the blood group system and ability of antibodies of the system to cause
haemolytic transfusion reaction and HDFN. The prevalence of ABO blood groups varies from race to race. In this
present study, we observed that 55.4% of subjects were blood group O, 23.8% were blood group B, 17.6% were
group A and 3.2% were group AB. Gene frequencies with respect to the ABO system for the present study has
shown a general formula O > B > A > AB indicating a preponderance of allele B over allele A. Our finding is
consistent with previous report among Guinean population in which the frequencies of the genes A, B and O in the
population were 14.70, 15.48, 69.83 respectively [13]. Our finding is however at variance with previous reports in
other parts of Nigeria; Erhabor and colleagues [9], Jerimiah [14], Worlledge and colleagues [15], Falusi and colleagues
[16] and Omotade and colleagues [17] which investigated the prevalence of ABO and Rh blood groups and obtained a
prevalence pattern (O > A > B > AB) among student of African descent in Port Harcourt, among students in the
Niger Delta, among the Yoruba and Hausa ethnic groups, in five zone of Nigeria and in Ibadan respectively.
However, some Eastern Europeans have a higher proportion (up to 40%) of group B blood [18]. Ethnic
American Indians belong exclusively to blood group O while American blacks generally demonstrate frequencies of
O, A, B, and AB blood groups of 49%, 27%, 20% and 4%, respectively (O > A > B > AB)2. Also a previous study to
determine the frequency of ABO and Rh blood group antigens among 4,656 neonates born at a private hospital in
Istanbul indicated that group A blood was detected most frequently followed by group O, group B, and group AB [19].
A study conducted to determine the frequency of ABO and Rhesus (Rh) blood groups in Pakistan indicated that
group B was the predominant blood group [20]. The most frequent blood group in Saudis is O-positive. Blood group A
is observed at a lower frequency relative to values from Western populations, whereas a significant increase in
blood group B combined with a slight increase in blood group AB [21]. The gene frequencies among residents of
Bangal, India with respect to ABO systems show a pattern (O > B > A > AB). Blood group O was the highest (35.8%)
and the least percentage distribution was blood group AB (6.68%). The frequencies of A (+), B (+), AB (+,) and O (+)
blood in West Bengal, India were 22.44%, 33.61%, 6.58%, and 35.07%, respectively [22]. A study that evaluated the
distribution of ABO and Rhesus (Rh) D blood groups in the population of Poonch district in Azad Jammu and
Kashmir showed the same trend of prevalence as for the general Indian subcontinent (B > or = O > A > AB) [23] .
ABO frequencies observed among Mauritanian population in a previous report were of the order of O > A > B [24].
Previous reports [14,15,16,17] are however in agreement with the frequencies obtained in this study and
confirm that group O is the predominant ABO blood group among Nigerians. There is however an exception to this
rule. Previous report [25] among the Gwari tribe of Abuja and the Rubuka tribe of the Plateau state in Northern
Nigeria has shown that blood group B was the predominant ABO blood group. The reason for this exception may be
due to high rate of intra-tribal marriages prevalent among the Gwari and Rubuka tribe. The high prevalence of group
e-ISSN: 2319-9865
p-ISSN: 2322-0104
RRJMHS | Volume 2 | Issue 4 | October-December, 2013 61
O observed in this present study among the people of Gusau in North Western Nigeria seems an advantage
particularly in terms of optimizing the use of scare blood resource by potentially utilizing the blood group O stock
against ABO blood group barriers for patients of other blood groups (A, B and AB) particularly in emergency
situations. Blood group O individuals lack ABO blood group antigens on their red cell and thus are termed universal
donors. Such blood can potentially be transfused to patients of blood groups A, B and AB. However, there is a
caveat to this rule and some level of caution need to be exercised. This is particularly true because the plasma of
some blood group O blood individuals has been shown to contain high titer of potent A and B immune haemolytic
antibodies (haemolysins) that can potentially cause the haemolysis of red cells containing antigen A and B.
Evidence –based best practice in the developed world advocate for the routine testing of all blood group O donor
blood for the presence of these α and β haemolysin and that those containing high titer haemolysin should be
reserved specifically for group O patients only. Those samples which are negative for high titer haemolysin could be
given to groups A, B, and AB individuals in emergency situations, when ABO group specific units are not
immediately available.
The Rhesus blood group system is the second most clinically significant red cell antigen system after the
ABO blood group system. Rh incompatible transfusions are also potentially fatal to health [26]. In this study, we
observed the prevalence of Rhesus positive and negative among 98.8% and 1.2% respectively. Our finding is
consistent with previous reports obtained among non-Caucasians. Erhabor and colleagues [9] in the Niger Delta of
Nigeria observed that 93% of their subjects were Rhesus positive while the remaining 7% of the study population
were negative. Egesie and co-workers [27] observed Rh-D positive and negative rates of 98% and 2% respectively
among their cohort of undergraduate students in the Niger Delta of Nigeria. Similarly, 96.7% positive rate was
recorded among the Ibos ethnic group of Eastern Nigeria by Ukaejiofor et al [28]. Other documented Rh-D positive
rates includes; 95% by Jeremiah and coworkers [29] in Port Harcourt, 96.6% by Pramanik et al [18] in Nepal, 94% by
Mwangi in Kenya [30], 93% by Bashwari et al [21] in the Eastern region of Saudi Arabia, 97.7% in West Bengal India
[22], 95.94% in Guinea [13] and 92.8% by Sarhan et al [31] in Southwest of Saudi Arabia.
This percentage of Rh (D) negative observed in our study (1.2%) is significantly lower than the prevalence
rate of >14% Rh (D) negative phenotype observed in studies among Caucasians [32,33]. There are several obstetric
advantages associated with the low prevalence of D-negative in Gusau. The risk of Rh (D) alloimmunization will be
of a much smaller magnitude than it is in most western countries where a significant proportion of the population
lacks the major Rh (D) antigen. In such individuals, the chances of becoming sensitized to the D antigen following
exposure either by transfusion of Rh(D) positive red cells or during pregnancy involving a Rhesus positive foetus is
very high. Alloantibody D produced as a result of such immunization has serious clinical significance including
haemolytic disease in the newborn and/or transfusion reactions. Despite the fact that the prevalence of Rh-
negative phenotype is significantly lower among Africans compared to Caucasians, Rh alloimmunization remains a
major factor responsible for perinatal morbidity in most developing countries for several reasons; lack of universal
access and unaffordability of anti-D immunoglobulin, lack of anti-D prophylaxis in Rhesus negative women who
have a potentially sensitizing events during pregnancy (amniocentesis, cordocentesis, antepartum haemorrhage,
vaginal bleeding during pregnancy, external cephalic version, abdominal trauma, intrauterine death and stillbirth, in
utero therapeutic interventions, miscarriage, and therapeutic termination of pregnancy), unavailability of
prophylactic immunoglobulin D follow termination of pregnancy among Rhesus negative women and unavailability
of FMH measurements following potentially sensitizing events during pregnancy.
In this present study we observed a higher prevalence of group O, A, B, AB and Rhesus positive among
male donors compared to females. This male gender associated higher prevalence may be due to the fact that the
number of male subjects in this study was significantly higher compared to female subjects. Most studies in Africa
report a male dominance in blood donation program (61% in Togo), (71.2% in Burkina Faso) and (90% in Ghana)
[34,35,36]. A recent study in 7 countries in central, western and eastern francophone Africa regions reported less than
30% females in their donor population [3 7]. Reports from Anglophone East and Southern African countries have also
shown a male dominance in blood donation program. The reason for this male gender predisposition to blood
donation in the African population is based on the erroneous belief that men are healthier than women [38] coupled
with the general belief that women make monthly blood donations to nature through their menstrual cycle. Other
factors such as pregnancy and breastfeeding further restrict many women from donating blood in SSA.
Interestingly, this pattern seems to differ significantly from what obtains in some European countries. In 2003,
female blood donors represented 40% in Austria, 49·7% in France, 50% in Norway and 55% in Great-Britain blood
donor populations.
ACKNOWLEDGEMENT
The author wishes to acknowledge all the subjects included in this study for their collaboration. We are
also grateful to staff at the Faculty of Medical laboratory Science in the Department of Haematology in Usmanu
Danfodiyo University (UDUS) in Sokoto, Nigeria.
e-ISSN: 2319-9865
p-ISSN: 2322-0104
RRJMHS | Volume 2 | Issue 4 | October-December, 2013 62
REFERENCES
1. Pramanik T, Pramanik S. Distribution of ABO and Rh blood groups in Nepalese Medical Students: a report.
East Mediterr Health J. 2000; 6(1):156–158.
2. Conteras M, Lubenko A. Immunohaematology: Introduction. In: Hoffbrand AV, Lewis SM, Tuddenham EGD,
editors. Postgraduate haematology. 4th ed. London UK: Arnold Publishers; 2001. pp. 165–181.
3. Knowles S, Poole G. Human blood group systems. In: Murphy MF, Pamphilon DH, editors. Practical
transfusion medicine. 1st ed. London, UK: Blackwell Science; 2002. pp. 24–31.
4. Knowles S, Poole G. Human blood group systems. In: Murphy MF, Pamphilon DH, editors. Practical
Transfusion Medicine. 1st ed. London, UK: Blackwell Science; 2002: 24–31.
5. Bhat YR, Kumar CG. Morbidity of ABO haemolytic disease in the newborn. Paediatr Int Child Health. 2012;
32(2):93-96.
6. Mandisodza AR, Mangoyi G, Musekiwa Z, Mvere D, Abayomi A. Incidence of haemolytic disease of the
newborn in Harare, Zimbabwe. West Afr J Med. 2008; 27(1):29-31.
7. Hughes RG, Craig JI, Murphy WG, Greer IA. Causes and clinical consequences of Rhesus (D) haemolytic
disease of the newborn: a study of a Scottish population, 1985-1990.Br J Obstet Gynaecol. 1994; 101(4):
297-300.
8. Bakare AA, Azeez MA, Agbolade JO. Gene frequencies of ABO and Rhesus blood groups and haemoglobin
variants in Ogbomosho, South - West, Nigeria. Global J Med Sci. 2004; 3(3):17–22.
9. Erhabor O, Adias TC, Jeremiah ZA and Hart ML. Abnormal hemoglobin variants, ABO, and Rhesus blood
group distribution among students in the Niger Delta of Nigeria. Pathology and Laboratory Medicine
International. 2010; 2: 6-12.
10. Worlledge S, Ogiemudia SE, Thomas CO, Ikoku BN, Luzzatto L. Blood group antigens and antibodies in
Nigeria. Ann Trop Med Parasitol. 1974; 68: 249–264.
11. Judd JW. Methods in Immunohematology. 2nd edn. Durham, USA: Montogomery Scientific Publications;
1994.
12. Brecher M. Technical Manual. 14th ed. Bethesda, USA: American Association of Blood Banks; 2002.
13. Loua A, Lamah MR, Haba NY, Camara M. Frequency of blood groups ABO and rhesus D in the Guinean
population. Transfus Clin Biol. 2007; 14(5): 435-439.
14. Jeremiah ZA. Abnormal haemoglobin variants, ABO and Rh blood groups among student of African descent
in Port Harcourt, Nigeria. Afr Health Sci. 2006; 6: 177–181.
15. Worlledge S, Ogiemudia SE, Thomas CO, Ikoku BN, Luzzatto L. Blood group antigens and antibodies in
Nigeria. Ann Trop Med Parasitol. 1974; 68: 249–264.
16. Falusi AG, Ademowo OG, Latunji CA, Okeke AC, Olatunji PO, Onyekwere TO, Jimmy EO, Raji Y, Hedo CC,
Otukonyong EE, et al. Distribution of ABO and RH genes in Nigeria. Afr J Med Med Sci. 2000; 29(1): 23 -26.
17. Omotade OO, Adeyemo AA, Kayode CM, Falade SL, Ikpeme S. Gene frequencies of ABO and Rh (D) blood
group alleles in a healthy infant population in Ibadan, Nigeria. West Afr J Med. 1999; 18(4): 294-297.
18. Pramanik T, Pramanik S. Distribution of ABO and Rh blood groups in Nepalese Medical Students: a report.
East Mediterr Health J. 2000; 6(1): 156–158.
19. Kayiran SM, Oktem O, Kayiran PG, Paloglu E, Gurakan B. Frequency of ABO and rhesus blood groups
among neonates born at a private hospital in Istanbul. Southeast Asian J Trop Med Public Health. 2012;
43(2): 467-470.
20. Khattak ID, Khan TM, Khan P, Shah SM, Khattak ST, Ali A. Frequency of ABO and Rhesus blood groups in
District Swat, Pakistan. J Ayub Med Coll Abbottabad. 2008; 20(4): 127-129.
21. Bashwari LA, Al-Mulhim AA, Ahmad MS, Ahmed MA. Frequency of ABO blood groups in the Eastern region of
Saudi Arabia. Saudi Med J. 2001; 22(11): 1008-1012.
22. Mondal B, Maiti S, Biswas BK, Ghosh D, Paul S. Prevalence of hemoglobinopathy, ABO and rhesus blood
groups in rural areas of West Bengal, India. J Res Med Sci. 2012; 17(8): 772-776.
23. Khan MN, Khaliq I, Bakhsh A, Akhtar MS, Amin-ud-Din M. Distribution of ABO and Rh D blood groups in the
population of Poonch District, Azad Jammu and Kashmir. East Mediterr Health J. 2009; 15(3): 717-721.
24. Hamed CT, Bollahi MA, Abdelhamid I, Med Mahmoud MA, Ba B, Ghaber S, Habti N, Houmeida A.
Frequencies and ethnic distribution of ABO and Rh(D) blood groups in Mauritania: results of first
nationwide study. Int J Immunogenet. 2012; 39(2): 151-154.
25. Egesie UG, Egesie OJ, Usar I, Johnbull TO. Distribution of ABO, Rhesus blood groups and haemoglobin
electrophoresis among the undergraduate students of Niger Delta University Nigeria. Niger J Physiol Sci.
2008; 23: 5–8.
26. Onwukeme KE. Blood group distribution in blood donors in a Nigerian population. J Physiol Sci. 1990; 6(1):
67–70.
27. Akhigbe RE, Ige SF, Afolabi AO, Azeez OM, Adegunlola GJ, Bamidele JO. Prevalence of haemoglobin
variants, ABO and rhesus blood groups in ladoke akintola University of Technology, Ogbomoso, Nigeria.
Trends Med Res. 2009; 4: 24–29.
28. Ukaejiofor EO, Okonkwo WC, Tagbar EN, Emeribe AO. Blood Transfusion in the Tropics. Nigeria: (Ukaejiofor
EO) Salem Press; 1996. ABO and Rhesus in a Nigerian population; pp. 1–22.
e-ISSN: 2319-9865
p-ISSN: 2322-0104
RRJMHS | Volume 2 | Issue 4 | October-December, 2013 63
29. Jeremiah ZA, Buseri FI. Rh antigens and phenotype frequencies and probable genotypes for the four ma in
ethnic groups in Port Harcourt Nigeria. Immunohematology. 2003; 19(3): 86–88.
30. Mwangi J. Blood group distribution in an urban population of patient targeted blood donors. East Afr Med J.
1999; 76(11): 615-618.
31. Sarhan MA, Salem KA, Bin-Dajem SM. Distribution of ABO blood groups and Rhesus factor in Southwest
Saudi Arabia. Saudi Med J. 2009; 30: 116–119.
32. Bergstrom S, Pereira C, Hagstrom U, Safwenberg J. Obstetric impli- cations of Rhesus antigen distribution
in Mozambican and Swedish women. Gynecol Obstet Invest. 1994; 38: 82–86.
33. Cerny T, Fey MF, Oppliger R, et al. Prevalence of the Rhesus – negative phenotype in Caucasian patients
with small-cell lung cancer (SCLC). Int J Cancer. 2006; 52: 504–506.
34. Allain JP, Sarkodie F, Boateng P, Asenso K, Kyeremateng E, Owusu-Ofori S. A pool of repeat blood donors
can be generated with little expense to the blood centre in sub-Saharan Africa. Transfusion. 2008; 48:
735–741.
35. Tayou Tagny C, Mbanya D, Diarra A, et al. Characteristics of blood donors and donated blood in
Francophone Africa. Transfusion. 2009; doi: 10.1111/j.1537 2995.2009.02137.
36. Cunha L, Plouzeau C, Ingrand P, Gudo JP, Ingrand I, Mondlane J, Beauchant M, Agius G. Use of
replacement blood donors to study the epidemiology of major blood-borne viruses in the general
population of Maputo, Mozambique. Journal of Medical Virology. 2007; 79: 1832–1840.
37. Rajab JA, Muchina WP, Orinda DA, Scott CS. Blood donor hematology parameters in two regions of Kenya.
East African Medical Journal.2005; 82: 123–127.
38. Lefrère JJ, Rouger P. Pratique Nouvelle de la Transfusion Sanguine. 2nd edition. Paris, France: Masson;
2006.