Demographic profile of blood donors at three major Brazilian blood centers: results from the International REDS-II study, 2007 to 2008

Irregular red blood cell antibodies, abnormal hemoglobin and dangerous universal blood donor insights from a public blood center in a Brazilian metropolitan area

BACKGROUND

Immunohematology tests are crucial in transfusion safety. This study aimed to assess irregular red blood cell (RBC) antibodies, abnormal hemoglobin and dangerous universal blood donors at a public blood center in a Brazilian metropolitan area.

METHODS

A cross-sectional study included all consecutive blood donors from January 2018 to December 2021 at the Brasília Blood Center Foundation, Federal District (FD), Brazil.

RESULTS

Among 205,965 blood donations, irregular RBC antibodies were found in 743 (0.4 %). Abnormal hemoglobin was observed in 5396 (2.6 %): 3959 (1.9 %) with Hb AS, 1344 (0.7 %) with Hb AC, and 93 (< 0,1 %) with other hemoglobin variants. Of O group donors, 12.5 % (9646) had hemolysins: 12.5 % (2410) both anti-A and anti-B, 8.7 % (9646) only anti-A, and 1.6 % (1763) only anti-B hemolysins. Female sex (p < 0.001) and increasing age (p < 0.001) were associated with irregular RBC antibodies. O and/or Rh(D)-positive blood groups had a lower prevalence of irregular RBC antibodies compared to other ABO and/or Rh(D)-negative groups. Age (p < 0.001) and female sex (p < 0.001) were associated with anti-A/anti-B hemolysins, while FD residency was associated with reduced incidence (p < 0.001).

CONCLUSION

Anti-A/anti-B hemolysins in O group donors, abnormal hemoglobin and irregular RBC antibodies pose risks to transfusion practice and should not be overlooked. Advancing age, female sex, ABO blood group other than O, or Rh(D)- negative are independently associated with the presence of irregular RBC antibodies. Dangerous universal blood donors were associated with advanced age, female gender, Rh(D)-positive blood type, and individuals residing in a Brazilian state other than where the blood center was located.

Comparison of Two Methods of Capillary Sampling in Blood Pre-Donation Anemia Screening in Brazil

BACKGROUND

The laboratory tests most used by blood banks to diagnose anemia are the hemoglobin (Hb) and microhematocrit (Hct) tests, measured from capillary samples.

OBJECTIVE

To analyze the two capillary screening methods for pre-donation anemia by comparing their agreement in diagnosing anemia.

METHOD

A cross-sectional study in a population of 15,521 blood donation candidates for whom information was available on Hb and Hct, performed from capillary blood samples. Hb was determined using the HemoCue^® test and Hct by the centrifugation method. The Kappa coefficient was calculated to assess the agreement between the methods. Pearson's correlation tests and gender-adjusted linear regression were used to assess the change in the response variable (Hb) as a function of the explanatory variable (Hct).

RESULTS

The majority of the study population were men (70.4%), aged between 18 and 44 years (72.1%), who declared themselves white or mixed skin color (85.6%), and had undergone at least 11 years of complete education (72.4%). The Kappa coefficient found was 92.7 and 99.2 for women and men, respectively. Pearson's correlation showed a correlation coefficient of 0.98 and the linear regression graph showed an adequate relationship between the tests with R² = 0.97.

CONCLUSIONS

Comparing the Hb and Hct capillary tests, it was found that Hct can be safely used to screen for anemia in pre-blood donation.

Blood components use at two private hospitals in Belo Horizonte, Minas Gerais between July 2017 and June 2019

INTRODUCTION

A retrospective ecological longitudinal study was carried out with data on blood components use from two private hospital units that belong to the same organization located in Belo Horizonte between July 2017 and June 2019.

OBJECTIVES

To describe the monthly series of red blood cells, platelets and plasma use and the rate of blood components use for general hospitalizations in the health network, from the perspective of time series.

METHODS

A total of 15 time series were created with monthly data related to the use of blood components. The stationarity of the series was verified by the unit root test, the trend, by the Cox-Stuart test and seasonality, by the Fisher test (significance levels of 10% for the first test and 5% for the last two).

RESULTS

All series tested positive for the trend component and showed an increasing trend for the use of blood components. Ten series showed statistically significant seasonality and eight series were identified as non-stationary. The percentage of transfusions of blood components due to hospitalization at hospitals 1 and 2 was 29% (22% at hospital 1 and 38.9% at hospital 2).

CONCLUSION

This study was able to describe the components of blood components use dynamics, from the perspective of time series at hospitals. Due to the growing trend in demand for blood components and their high cost, we propose the reduction of blood components use and the expanded use of alternative blood transfusion strategies.

Detection and analysis of blood donors seropositive for syphilis

BACKGROUND

The increasing incidence of syphilis worldwide has called attention to the risk of transmission by transfusion.

AIMS

To determine the prevalence of active syphilis in blood donors and characterise the serological profile of syphilis-positive donors.

METHODS

Samples positive for Treponema pallidum using the chemiluminescent microparticle immunoassay (CMIA) during blood donor screening from 2017 to 2018 were tested by the Venereal Disease Research Laboratory (VDRL) non-treponemal test and for anti-T. pallidum IgM by ELISA (Immunoassay Enzyme test for detection of IgM antibodies). The INNO-LIA Syphilis test (Line Immuno Assay solid test for confirmation antibodies to Treponema pallidum) was performed as a confirmatory test on samples that were positive on ELISA-IgM but negative on VDRL. ELISA-IgM (+) samples were also tested for T. pallidum DNA in sera by real-time polymerase chain reaction (PCR).

RESULTS

Of 248 542 samples screened, 1679 (0.67%) were positive for syphilis by CMIA. Further analysis was performed on 1144 (68.1%) of these samples. Of those tested, 16% were ELISA IgM(+)/VDRL(+), 16.5% were ELISA IgM(-)/VDRL(+), 4.1% were ELISA IgM(+)/VDRL(-), and 63.4% were ELISA IgM (-)/VDRL(-). The INNO-LIA Syphilis test results were 33 (3%) positive, 2 (0.2%) undetermined and 12 (1%) negative. Of the 230 EIA-IgM(+) samples (20.1%), 5 (2.2%) were PCR positive. The prevalence of active syphilis in 2017 and 2018 was 0.1% and 0.07%, respectively, and overall prevalence of serologic markers for syphilis was highest among male, unmarried, 25-34-year-olds with a high school education and who were first-time donors.

CONCLUSION

There is a risk of transfusion-transmitted syphilis in blood banks that exclusively use the VDRL test for donor screening, as is currently the situation in some Brazilian blood centres, as well as in other blood centres around the world.

Demographical Pattern of Blood Donors and Pre-Donation Deferral Causes in Dhahran, Saudi Arabia

Background

Understanding the demographic features of blood donors is important for identifying the donor structure and guiding the recruitment and retention strategies of donors. This study was aimed to determine the demographic characteristics of blood donors, the types of donation drives, and the frequency and reasons for pre-donation deferral in our population.

Methods

This cross-sectional study included data analysis of all prospective blood donors presenting themselves for donation at the Blood Bank of the King Fahad Military Medical Complex, Dhahran, Saudi Arabia between January 2010 and December 2018. Eligibility of blood donation was assessed using a standardized history questionnaire, physical examination, hemoglobin estimation, pulse rate, blood pressure, and temperature. The questionnaire included the demographic features of the donor such as age, gender, and the reason for donation and other specific risk factors that potentially affect the safety of the donor or the recipient. Data analyzed using the analysis of SPSS version 20 (SPSS Inc., Chicago, IL, USA) were used to calculate the unadjusted odds ratios (OR) and the respective 95% confidence interval for the association between the various demographic parameters.

Results

A total of 28,189 potential donations were recorded during the study period; of these, 77.4% were family replacements with females accounting for only 1.8% of all donations. Most of the donors were Saudi nationals (92.1%) of whom donors between 18 and 34 years old constituted 87.9%, while those over 40 years old represented only 7.9% of the donations. Pre-donation temporary deferral occurred in 3300 (11.7%) of all potential donation attempts. The most common causes being the recent intake of medication (24.4%) followed by low hemoglobin (14.8%), low or high blood pressure (14.6%), low or high pulse rate (13.6%), and low weight (11.6%).

Conclusion

A profile of blood donors consisting mainly of young male citizens who mostly donated for family replacement was detected. Deferral rate was found to be average when compared to other countries; the causes being similar to those detected in other developed countries. Simple descriptive statistics has shown no marked difference was noted over the 9 years of the study in neither the profile of blood donors nor the cause for temporary deferral of prospective blood donors.

What are the perspectives for blood donations and blood component transfusion worldwide? A systematic review of time series studies

BACKGROUND

Analysis of the literature suggests that changes relating to blood donations and blood component transfusion are occurring due to the aging of the population.

OBJECTIVE

To gain better understanding of the demand and supply of these inputs over time, and to identify the main associated demographic characteristics.

DESIGN AND SETTING

Systematic review conducted on time series relating to blood donations and blood component transfusions worldwide.

METHODS

A systematic review of the literature was conducted based on articles that presented time series relating to blood donation or blood component transfusion.

RESULTS

We found 1,814 articles. After the deletion process, only thirteen were read. Overall, these suggested that there is increasing demand for blood components and decreasing donation. The existence of seasonality regarding blood donation was pointed out. Men usually donated more blood and demanded more blood components than women. Approximately 50% of blood transfusions were performed in people aged ≥ 60 years.

CONCLUSIONS

This analysis on articles that presented time series relating to blood donations and blood component transfusion showed that aging of the population was the main factor associated with the increasing demand for blood and the decreasing supply of blood.

Does deferral for high-risk behaviors improve the safety of the blood supply?

BACKGROUND

Predonation donor deferral is used to select donors with presumed lower risk for transfused transmitted infections. The contribution to blood safety from this practice has not been reported previously for Brazil.

STUDY DESIGN AND METHODS

At four large Brazilian blood centers from September 2010 to March 2011, donors who were deferred due to responses on eligibility questions were invited to provide a blood sample to test for HIV, hepatitis C virus, hepatitis B virus, human T-lymphotropic virus, syphilis, and Trypanosoma cruzi and complete an audio computer-assisted structured interview on risk behaviors.

RESULTS

Of 299,848 potential donors during the study period, 66,870 were deferred with 10,453 (15.6%) for high-risk behaviors. Of those, 4860 (46.5%) were consecutively approached and 4013 (82.5%) participated. Disclosed risk behaviors by audio computer-assisted structured interview included 4 or more sexual partners in the past 12 months (15.0% of females [F] and 34.5% of males [M]), unprotected sex (62.0% F and 44.0% M), other high-risk sexual exposure (85.0% F and 73.0% M), being a person who injects drugs (3.0% F and 10.0% M), and test-seeking (17.0% F and 22.0% M). Eleven percent of deferred males reported male-to-male sex. Individuals who reported other high-risk sexual exposure, sexual partner risk, or male-to-male sex had the highest frequency of confirmed HIV: 1.2, 0.7, and 0.7%, respectively. Individuals who reported male-to-male sex, sexual partner risk, test seeking, and unprotected sex had the highest frequency of confirmed syphilis: 3.8, 3.3, 2.4, and 2.0%, respectively.

CONCLUSION

Donor deferral deters donation by individuals with risk behaviors and elevated rates of infectious disease markers.

Comparison of the demographic and social profile of blood donors and nondonors in Brazil

Population-based studies on blood donation prevalence and its association with sociodemographic and behavioural factors are scarce, but remain the best approach to assess correlates of donation, including those which could be the target for donor recruitment campaigns. This study describes the population of primary healthcare users from the public system in a medium-sized Brazilian municipality to investigate the association of blood donation practice with other sociodemographic factors. A stratified, representative sample of primary healthcare users at 12 healthcare facilities in Ribeirão Preto, São Paulo, Brazil, were invited to participate. Analysis focused on demographic and psychosocial factors including, sex, age, marital status, socioeconomic status, educational level, health insurance, self-perception of health, religious beliefs, and blood donation history. Blood donors, self-defined ineligible donors, and never donors were compared. Multiple correspondence analysis (MCA) was used to assess positively and negatively associated variables in the dataset. MCA was conducted on respondents' age and monthly household income to assess dimensionality of other questionnaire responses. Of a total of 1,055 study participants, 79.7% were females and the mean age was 40.6 years. Blood donation practice was reported by 246 participants (23.3%), 669 (63.4%) had never donated, and 140 (13.3%) reported being unable to donate blood. Graphical presentation of the MCA showed that male, older age groups, those who have health insurance, and with higher socioeconomic and educational level are more likely to donate blood. Poor or average self-perception of health, lower socioeconomic status, and divorced or widowed marital status were associated with self-defined inability to donate blood. Thus, our results are useful to understand the multifactorial nature of blood donation behaviour. Our findings provide guidance for targeted recruitment campaigns focused on relevant contextual factors. The focus on reducing barriers to blood donation according to sociodemographic groups can be a relevant strategy to expand the donor base.

Changes in health and disease in Brazil and its States in the 30 years since the Unified Healthcare System (SUS) was created

The Unified Healthcare System (SUS) was created to ensure the population's right to universal, free and comprehensive healthcare. This study compares the health indicators measured in 1990 to those measured in 2015 in Brazil and its states. The goal is to contribute to understanding the role SUS played in changing the nation's health profile. Analyses use estimates in the Global Burden of Disease (GBD) study for Brazil and its states, and compares 1990 and 2015. The main results are increased life expectancy, as well as an increase in the population's longevity measured in health-adjusted life expectancy. These in turn are due to a sharp decline in mortality due to transmissible diseases, in maternal and infant morbi-mortality, and avoidable causes of death. NTCDs are the leading cause of death, followed by violence. Poor diet is the leading risk factor, followed by metabolic issues. Tobacco use decreased over the period, as did infant malnutrition. In the thirty years since the SUS was created, health indicators in this country have improved, and major progress has been made to reduce inequality across the country's regions.

Burden of disease in Brazil, 1990-2016: a systematic subnational analysis for the Global Burden of Disease Study 2016

BACKGROUND

Political, economic, and epidemiological changes in Brazil have affected health and the health system. We used the Global Burden of Disease Study 2016 (GBD 2016) results to understand changing health patterns and inform policy responses.

METHODS

We analysed GBD 2016 estimates for life expectancy at birth (LE), healthy life expectancy (HALE), all-cause and cause-specific mortality, years of life lost (YLLs), years lived with disability (YLDs), disability-adjusted life-years (DALYs), and risk factors for Brazil, its 26 states, and the Federal District from 1990 to 2016, and compared these with national estimates for ten comparator countries.

FINDINGS

Nationally, LE increased from 68·4 years (95% uncertainty interval [UI] 68·0-68·9) in 1990 to 75·2 years (74·7-75·7) in 2016, and HALE increased from 59·8 years (57·1-62·1) to 65·5 years (62·5-68·0). All-cause age-standardised mortality rates decreased by 34·0% (33·4-34·5), while all-cause age-standardised DALY rates decreased by 30·2% (27·7-32·8); the magnitude of declines varied among states. In 2016, ischaemic heart disease was the leading cause of age-standardised YLLs, followed by interpersonal violence. Low back and neck pain, sense organ diseases, and skin diseases were the main causes of YLDs in 1990 and 2016. Leading risk factors contributing to DALYs in 2016 were alcohol and drug use, high blood pressure, and high body-mass index.

INTERPRETATION

Health improved from 1990 to 2016, but improvements and disease burden varied between states. An epidemiological transition towards non-communicable diseases and related risks occurred nationally, but later in some states, while interpersonal violence grew as a health concern. Policy makers can use these results to address health disparities.

FUNDING

Bill & Melinda Gates Foundation and the Brazilian Ministry of Health.

Awareness of and attitude towards blood donation in students at the Semnan University of Medical Sciences

Background

Despite the increasing demands for blood and its products, some people, especially the youth, have little interest in donating blood.

Objective

This study aimed to assess the university students’ awareness of and attitude towards blood donation.

Methods

In this cross-sectional study, a descriptive analytical approach was used to examine awareness of and attitude towards blood donation among students in Semnan University of Medical Sciences, Semnan, Iran. The study was performed in 2015–2016. A total of 749 university students participated in this study. A special questionnaire was used to collect demographic information and the participants’ awareness of and attitude towards blood donation. Before beginning the main phase of the study, the reliability and validity of the questionnaire were examined and verified. The SPSS software, version 16, was used for statistical analysis. We used descriptive statistics, specifically chi-square and Friedman tests, to analyze the data. A p-value of <0.05 was considered significant.

Results

63.55% of the participants were female. Only 9.74% of the participants had a history of blood donation. Based on the results, 253 participants (35.33%) had low awareness, 352 participants (49.16%) had moderate awareness, and 111 participants (15.5%) had good awareness of blood donation. In addition, 176 participants (23.59%) had negative attitude, 438 participants (58.71%) had moderate attitude, and only 132 participants (17.69%) had good attitude towards blood donation. Results also showed a statistically significant relationship between gender and awareness of the history of blood donation (p=0.047). However, there was no significant relationship between gender and attitude towards blood donation (p=0.27). When asked about their favorite method of receiving information about blood donation, 376 participants (50.2%) preferred social media.

Conclusion

A considerable percentage of students have low awareness of and negative attitude towards blood donation. The low awareness and negative attitude towards blood donation can be considered as important factors contributing to the lack of interest and poor participation in blood donation among this population. Therefore, there is a critical need for training and culture building activities and programs in order to increase university students’ awareness and improve their attitude towards blood donation.

Ribeiro AL, Cerdeira Sabino E. Mortality among blood donors seropositive and seronegative for Chagas disease (1996-2000) in São Paulo, Brazil: A death certificate linkage study

Background

Individuals in the indeterminate phase of Chagas disease are considered to have mortality rates similar to those of the overall population. This study compares mortality rates among blood donors seropositive for Chagas disease and negative controls in the city of São Paulo, Brazil.

Methodology/principal findings

This is a retrospective cohort study of blood donors from 1996 to 2000: 2842 seropositive and 5684 seronegative for Chagas disease. Death status was ascertained by performing probabilistic record linkage (RL) with the Brazil national mortality information system (SIM). RL was assessed in a previous validation study. Cox Regression was used to derive hazard ratios (HR), adjusting for confounders. RL identified 159 deaths among the 2842 seropositive blood donors (5.6%) and 103 deaths among the 5684 seronegative (1.8%). Out of the 159 deaths among seropositive donors, 26 had the 10th International Statistical Classification of Diseases and Related Health Problems (ICD-10) indicating Chagas disease as the underlying cause of death (B57.0/B57.5), 23 had ICD-10 codes (I42.0/I42.2/I47.0/I47.2/I49.0/I50.0/I50.1/ I50.9/I51.7) indicating cardiac abnormalities possibly related to Chagas disease listed as an underlying or associated cause of death, with the others having no mention of Chagas disease in part I of the death certificate. Donors seropositive for Chagas disease had a 2.3 times higher risk of death due to all causes (95% Confidence Interval (95% CI), 1.8–3.0) than seronegative donors. When considering deaths due to Chagas disease or those that had underlying causes of cardiac abnormalities related to Chagas disease, seropositive donors had a risk of death 17.9 (95% CI, 6.3–50.8) times greater than seronegative donors.

Conclusions/significance

There is an excess risk of death in donors seropositive blood for Chagas disease compared to seronegative donors. Chagas disease is an under-reported cause of death in the Brazilian mortality database.

Chagas disease is classified as one of the 17 most important neglected diseases by the World Health Organization (WHO). The majority of infected individuals live in 21 countries of Central and South America. Estimates of mortality attributable to Chagas disease vary considerably (between 0.2% and 19.2% annually). To improve the measurement of disease burden and policy decision-making in regard to treatment availability, more accurate estimates of mortality, especially among otherwise asymptomatic seropositive individuals are needed,. This study compares mortality rates and causes of death of asymptomatic blood donors who tested seropositive for Chagas disease and seronegative for all screening tests conducted in Brazil. Mortality status was ascertained by linking donor names with the Brazilian national mortality information system (SIM). The study found that donors who tested Chagas disease seropositive had risk of death from all causes 2.3 (95% CI, 1.8–3.0) times greater than seronegative ones. The data also suggest that the SIM may underestimate the total number of deaths attributable to Chagas disease in Brazil.

Socio-demographic characteristics of Danish blood donors

Background

Blood transfusion is an essential component of a modern healthcare system. Because knowledge about blood donor demography may inform the design of strategies for donor recruitment and retention, we used nationwide registers to characterize the entire population of blood donors in Denmark in 2010.

Methods

The study population comprised all Danes in the age range eligible for blood donation (N = 3,236,753) at the end of 2010. From the Scandinavian Donations and Transfusions (SCANDAT) register, we identified 174,523 persons who donated blood in Danish blood banks at least once in 2010. The association between sociodemographic characteristics and blood donor prevalence was examined using regression models.

Results

The overall prevalence of blood donation was 5.4% among both women and men. The age-specific prevalence of blood donation peaked at 25 years of age (6.8%) for women and 30 years of age (5.7%) for men. Children of any age were associated with lower prevalence of blood donation among women, while the opposite was seen for men. Middle to high income groups, but not the highest income group, had fourfold higher donor prevalence than the lowest income group (6.7% compared to 1.7%). The prevalence of blood donation was considerably lower among men living with their parents (2.9%) or alone (3.9%) than among men cohabitating with a woman (6.2%).

Summary

Social marginalization, as indicated by low income and being a male living without a woman, was associated with lower prevalence of blood donation. However, individuals with very high incomes and women with children were underrepresented in the Danish blood donor population.

Duration of Dengue Viremia in Blood Donors and Relationships Between Donor Viremia, Infection Incidence and Clinical Case Reports During a Large Epidemic

BACKGROUND

Dengue viruses (DENV-1-4) pose a transfusion-transmission risk. This study estimated the dengue RNA detection period in asymptomatic blood donors and relationships between donor viremia and dengue incidence during a large epidemic.

METHODS

Donor samples from the 2012 dengue transmission season in Rio de Janeiro, Brazil, were tested for DENV RNA by a transcription-mediated amplification (TMA) assay, with DENV types and viral loads determined by polymerase chain reaction. Samples collected during the first and last weeks of enrollment were tested for DENV immunoglobulin (Ig) G and IgM to estimate incidence during the study period, which was analyzed relative to nucleic acid amplification technology (NAT) yield to estimate the duration of NAT-detectable viremia and compared with reported clinical dengue cases in Rio.

RESULTS

Samples from 16 241 donations were tested; 87 (0.54%) were confirmed as DENV-4 RNA positive. Dengue IgM-positive/IgG-positive reactivity increased from 2.8% to 8.8%, indicating a 6.2% incidence (95% confidence interval [CI], 3.2%-9.1%) during the study period. Based on these data, we estimated a 9.1-day period (95% CI, 4.4-13.9 days) of RNA detectable with TMA. With 100 475 reported cases of clinical dengue, 1 RNA-positive donation was identified per 800 DENV cases.

CONCLUSIONS

These parameters allow projections of dengue incidence from donor NAT yield data and vice versa, and suggest that viremic donations will be rare relative to clinical disease cases.

Family donors are critical and legitimate in developing countries

INTRODUCTION

For many years, family blood donors have been considered less safe than volunteer non-remunerated blood donors and actively discouraged by international organisations and affluent countries support agencies for developing countries. In addition to safety, pressure and coercion was considered unethical. However these assumptions were not supported by evidence.

AIMS OF THE STUDY

To assemble recently collected evidence to reopen the assessment whether or not the ban of family blood donors is justified.

METHODS

Review of old and recent literature through Pubmed and references from identified articles.

RESULTS AND DISCUSSION

Viral marker data comparing confirmed seroprevalence in 1(st) time volunteer non-remunerated donors (VNRD) and family/replacement donors (FRD) corrected for gender and age, show no significant difference between the two groups. Evidence has been provided that for both VNRD and FAD benevolence is more appropriate than altruism. The two groups merge for psychological attitude to donation for which knowing someone needing transfusion is a powerful incentive to give blood. Excluding a life or death situation found in areas where severe blood shortage justifies replacement donation, pressures are exerted on both VNRD and FRD. There is no evidence of coercion of FRD. FRDs therefore meet all criteria for VNRD and are willing to become VNRD and to repeat donation. Ostracising FRD is illegitimate and damaging to the blood supply in resource poor areas. In some countries no difference is made between the two groups of donors representing similar populations asked to give blood in different circumstances.

CONCLUSIONS

FRDs remain a critical source of volunteer, non-remunerated, blood meeting all classical criteria of VNRD that should be considered legitimate and indispensable at this point in time instead of discouraged.

Blood donors in Iceland: a nationwide population-based study from 2005 to 2013

BACKGROUND

Demographic information of blood donors is important to formulate strategies for recruitment and maintenance of the donor group. Factors like aging population, increasingly advanced medical treatments, and growing safety initiatives to protect donors and recipients of blood components are likely to affect the size of the donor group in the future. The purpose of this study was to determine the size of the donor group in Iceland and describe the demographic and donation characteristics.

STUDY DESIGN AND METHODS

The size of the Icelandic donor group was determined and the demographic and donation characteristics described, particularly of all newly registered and whole blood donors in the country from 2005 to 2013.

RESULTS

Overall the prevalence of whole blood donors per population decreased by 24.2% between 2005 and 2013 or by 3.4% per year. Females and males were almost equally represented as newly registered donors (44.7%/55.3%) but males were better represented as whole blood donors (26.7%/73.3%). Only 57.5% of newly registered donors in 2005 to 2006 returned to donate blood in the period 2005-2013.

CONCLUSION

In parallel with a period of decreased demand for red blood cells, the number of whole blood donors and donations declined in Iceland between 2005 and 2013 but still with adequate supply. A smaller retention among females than males gives the opportunity to focus on increasing the share of women among regular blood donors. Strategic work toward effective recruitment and retention of newly registered donors is needed to ensure a sufficiently large group of blood donors in Iceland in the near future.

[Social marketing of blood donation: an analysis of new donors' predisposition]

This article aims to understand the motivational factors that influence individuals to donate blood, in order to support the social marketing measures for recruiting new donors. Based on theoretical research, a structural model was developed to analyze influences and interactions of constructs in individuals' intentions to donate blood. A field survey used a structured questionnaire with a sample of 346 individuals. The analysis included descriptive analysis, evaluation of psychometric consistency, and structural equation modeling with partial least squares estimation. Fear showed a negative influence and the reference group a positive influence on individual predisposition to donate blood. This indicated that social marketing for blood donation can be more effective in encouraging new donors if it remains focused on these two factors.

[Not Available]

The Retrovirus Epidemiology Donor Study (REDS) program was established in the United States in 1989 with the purpose of increasing blood transfusion safety in the context of the HIV/AIDS and human T-lymphotropic virus epidemics. REDS and its successor, REDS-II were at first conducted in the US, then expanded in 2006 to include international partnerships with Brazil and China. In 2011, a third wave of REDS renamed the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) was launched. This seven-year research program focuses on both blood banking and transfusion medicine research in the United States of America, Brazil, China, and South Africa. The main goal of the international programs is to reduce and prevent the transmission of HIV/AIDS and other known and emerging infectious agents through transfusion, and to address research questions aimed at understanding global issues related to the availability of safe blood. This article describes the contribution of REDS-II to transfusion safety in Brazil. Articles published from 2010 to 2013 are summarized, including database analyses to characterize blood donors, deferral rates, and prevalence, incidence and residual risk of the main blood-borne infections. Specific studies were developed to understand donor motivation, the impact of the deferral questions, risk factors and molecular surveillance among HIV-positive donors, and the natural history of Chagas disease. The purpose of this review is to disseminate the acquired knowledge and briefly summarize the findings of the REDS-II studies conducted in Brazil as well as to introduce the scope of the REDS-III program that is now in progress and will continue through 2018.

© 2014 Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular. All rights reserved.

Demographic, risk factors and motivations among blood donors with reactive serologic tests for syphilis in São Paulo, Brazil

OBJECTIVE

To identify the demographic characteristics, risk factors and motivations for donating among blood donors with reactive serologic tests for syphilis.

BACKGROUND

Post-donation interviews with syphilis seropositive blood donors improve recruitment and screening strategies.

METHODS

This case-control study compares 75 Venereal Disease Research Laboratory (VDRL) > 8, EIA+ (enzyme immunoassay) and FTA-ABS+ (fluorescent treponemal antibody); 80 VDRL-, EIA+ and FTA-ABS+; and 34 VDRL- and EIA- donors between 2004 and 2009. Donors were assessed by their demographic characteristics, sexual behaviour, history of alcohol and illicit drugs use, and motivations to donate.

RESULTS

Donors with VDRL > 8 were more likely to be divorced [AOR = 12·53; 95% confidence interval (CI) 1·30-120·81], to have had more than six sexual partners (AOR=7·1; 95% CI 1·12-44·62) and to report male-male-sex in the past 12 months (AOR=8·18; 95% CI 1·78-37·60). Donors with VDRL-, EIA+ and FTA-ABS+ were less likely to be female (AOR=0·26; 95% CI 0·07-0·96), more likely to be older (AOR=10·2; 95% CI 2·45-42·58 ≥ 39 and <60 years old) and to have had more than six sexual partners in the past 12 months (AOR = 8·37; 95% CI 1·49-46·91). There was no significant difference among groups regarding illicit drugs use; 30·7% (VDRL > 8) and 12·5% (VDRL-, EIA+ and FTA-ABS+) of donors reported that they had been at risk for HIV infection (P = 0·004). One-third of donors came to the blood bank to help a friend or a relative who needed blood.

CONCLUSION

Although donors exposed to syphilis reported and recognised some high risk behaviour, most were motivated by direct appeal to donate blood. Monitoring the risk profile of blood donors can benefit public health and improve blood safety.

Association between religiousness and blood donation among Brazilian postgraduate students from health-related areas

Objective

The aim of this study was to examine the association between religiousness and blood donation among postgraduate students.

Methods

The Portuguese-language version of the Duke University Religion Index was administered to a sample of 226 Brazilian students with ages ranging from 22 to 55 years. All study participants had completed undergraduate courses in health-related areas.

Results

In the present study, 23.5% of the students were regular donors. Organizational religiousness was found to be associated with attitudes related to blood donation. This study also shows evidence that regular blood donors have a higher intrinsic religiousness than subjects who donate only once and do not return.

Conclusion

This study shows that the attitudes concerning blood donation may have some association with religiosity.

[Prevalence of blood donation and associated factors in Florianópolis, Southern Brazil: a population-based study]

The main objectives of this study were to estimate the prevalence of blood donation and to identify associated factors. A populated-based cross-sectional study was carried out (n = 1,720) including subjects 20 to 59 years of age in Florianópolis, Santa Catarina State, Brazil. Blood donation any time in life and in the previous year was reported by 30.6% and 6.2% of respondents, respectively. Among the latter, 31.8% reported repeat donation (at least twice in the previous year), 80.4% reported voluntary donation, and 15.9% replacement donation. Multivariate Poisson regression (p < 0.05) showed that male gender, black or brown self-reported skin color, higher age group, higher educational level, and living with other blood donors were all associated with ever donating blood, whereas younger age, single marital status, and higher educational level were associated with donating in the previous year. We found higher prevalence of blood donation in the previous year and higher percentage of young donors in this group, as well as lower percentage of replacement donors than previously reported in Brazil.

Temporal distribution of blood donations in three Brazilian blood centers and its repercussion on the blood supply

Background

Seasonal distribution of blood donation hinders efforts to provide a safe and adequate blood supply leading to chronic and persistent shortages. This study examined whether holidays, geographical area and donation type (community versus replacement) has any impact on the fluctuation of donations.

Methods

The numbers of blood donations from 2007 through 2010 in three Brazilian Retrovirus Epidemiological Donor Study II (REDS-II) participating centers were analyzed according to the week of donation. The weeks were classified as holiday or non-holiday. To compare donations performed during holiday versus non-holiday weeks, tabulations and descriptive statistics for weekly donations by blood center were examined and time series analysis was conducted.

Results

The average weekly number of donations varied according to the blood center and type of week. The average number of donations decreased significantly during Carnival and Christmas and increased during the Brazilian National Donor Week. The fluctuation was more pronounced in Recife and Belo Horizonte when compared to São Paulo and higher among community donors.

Conclusion

National bank holidays affect the blood supply by reducing available blood donations. Blood banks should take into account these oscillations in order to plan local campaigns, aiming at maintaining the blood supply at acceptable levels.

HIV genotypes and primary drug resistance among HIV-seropositive blood donors in Brazil: role of infected blood donors as sentinel populations for molecular surveillance of HIV

BACKGROUND

There are few surveillance studies analyzing genotypes or primary (transmitted) drug resistance in HIV-infected blood donors in Brazil. The aim of this study was to characterize patterns of HIV genotypes and primary resistance among HIV-seropositive donors identified at 4 geographically dispersed blood centers in Brazil.

METHODS

All HIV-infected donors who returned for counseling at the 4 REDS-II Hemocenters in Brazil from January 2007 to March 2011 were invited to participate in a case-control study involving a questionnaire on risk factors. Viral sequencing was also offered to positive cases to assign genotypes and to detect and characterize primary resistance to reverse transcriptase and protease inhibitors according to World Health Organization guidelines.

RESULTS

Of the 341 HIV-seropositive donors who consented to participate in the risk factor and genetics study, pol sequences were obtained for 331 (97%). Clade B was predominant (76%) followed by F (15%) and C (5%). Primary resistance was present in 36 [12.2%, 95% confidence interval (CI) 8.2 to 15.5] of the 303 individuals not exposed to antiretroviral therapy, varying from 8.2% (95% CI: 2.7 to 13.6) in Recife to 19.4% in São Paulo (95% CI: 9.5 to 29.2); there were no significant correlations with other demographics or risk factors.

CONCLUSIONS

Although subtype B remains the most prevalent genotype in all 4 areas, increasing rates of subtype C in Sao Paulo and F in Recife were documented relative to earlier reports. Transmitted drug resistance was relatively frequent, particularly in the city of Sao Paulo which showed an increase compared with previous HIV-seropositive donor data from 10 years ago.

Methodological Guidelines for Reducing the Complexity of Data Warehouse Development for Transactional Blood Bank Systems

Over time, data warehouse (DW) systems have become more difficult to develop because of the growing heterogeneity of data sources. Despite advances in research and technology, DW projects are still too slow for pragmatic results to be generated. Here, we address the following question: how can the complexity of DW development for integration of heterogeneous transactional information systems be reduced? To answer this, we proposed methodological guidelines based on cycles of conceptual modeling and data analysis, to drive construction of a modular DW system. These guidelines were applied to the blood donation domain, successfully reducing the complexity of DW development.

Analysis of donor deferral at three blood centers in Brazil

BACKGROUND

The safety of the blood supply is ensured through several procedures from donor selection to testing of donated units. Examination of the donor deferrals at different centers provides insights into the role that deferrals play in transfusion safety.

STUDY DESIGN AND METHODS

A cross-sectional descriptive study of prospective allogeneic blood donors at three large blood centers located in São Paulo, Belo Horizonte, and Recife, Brazil, from August 2007 to December 2009 was conducted. Deferrals were grouped into similar categories across the centers, and within each center frequencies out of all presentations were determined.

RESULTS

Of 963,519 prospective blood donors at the three centers, 746,653 (77.5%) were accepted and 216,866 (22.5%) were deferred. Belo Horizonte had the highest overall deferral proportion of 27%, followed by Recife (23%) and São Paulo (19%). Females were more likely to be deferred than males (30% vs. 18%, respectively). The three most common deferral reasons were low hematocrit or hemoglobin, medical diagnoses, and higher-risk behavior.

CONCLUSION

The types and frequencies of deferral vary substantially among the three blood centers. Factors that may explain the differences include demographic characteristics, the order in which health history and vital signs are taken, the staff training, and the way deferrals are coded by the centers among other policies. The results indicate that blood donor deferral in Brazil has regional aspects that should be considered when national policies are developed.

Relationship between social capital and test seeking among blood donors in Brazil

BACKGROUND AND OBJECTIVES

Higher risk of HIV infection could be associated with test seeking, which is one motivation for donating blood. Cognitive social capital is defined as the social support, trust and co-operation that guide community behaviour. Structural social capital refers to an individual's participation in institutions and organizations. The association between social capital and test seeking was assessed.

MATERIALS AND METHODS

A survey of over 7500 donors in three Brazilian blood centres was conducted. Test seeking was classified into four non-overlapping categories (non-test seeker, possible, presumed and self-disclosed test seekers) using one direct and two indirect questions. Social capital was summarized into cognitive and structural categorizations. Multivariable logistic regression analysis was performed.

RESULTS

Compared with non-test seekers (62% of survey respondents), cognitive social capital was higher for each category of test seeking (OR=1.1, 7.4, 7.1, P<0.05 respectively). Male gender, lower education and lower income were also significantly associated with test seeking.

CONCLUSION

As test seekers appear to have strong social networks, blood banks may leverage this to convince them to seek testing at other locations.

The impact of policies to restrict the use of plasma containing products and apheresis platelets from female donors to mitigate transfusion related acute lung injury (TRALI) in Brazil

BACKGROUND AND OBJECTIVES

Although the incidence of TRALI is unknown in Brazil, some blood centers have adopted strategies to prevent TRALI. We evaluated the impact of three policies to mitigate TRALI on the supply of blood products: to divert the production of whole blood-derived plasma from female donors; to defer all female donors from apheresis platelet collections, and to defer only multiparous female donors from apheresis platelet collections.

MATERIALS AND METHODS

Data from allogeneic whole blood and apheresis platelet donations from April 2008 to December 2009 were collected in three Brazilian blood centers and the impact of the aforementioned strategies was evaluated.

RESULTS

Of 544,814 allogeneic blood donations, 30.8% of whole blood plasma and 24.1% of apheresis platelet donations would be reduced if only male donor plasma was issued for transfusion and all female donors were deferred from apheresis donation, respectively. If only multiparous donors were deferred from apheresis donation, there would be a 5% decrease of all apheresis platelet collections.

CONCLUSION

Restricting the use of whole blood derived plasma to male-only donors and deferring all female apheresis platelet donors would impact two out of three Brazilian blood centers. A deferral policy on multiparous apheresis platelet donors may be acceptable as a temporary measure, but may cause more stress on a system that is already working at its limit.

Human T-lymphotropic virus type 1 and type 2 seroprevalence, incidence, and residual transfusion risk among blood donors in Brazil during 2007-2009

Human T-lymphotropic virus type 1/2 (HTLV-1/2) infection is endemic in Brazil but representative donor prevalence and incidence data are lacking. All blood donations (2007-2009) from three blood centers in Brazil were studied. Samples reactive on one HTLV screening test (EIA) were retested with a different EIA; dual EIA reactivity correlated strongly with a confirmatory Western blot. Prevalence, incidence, and residual transfusion risk were calculated. Among 281,760 first-time donors, 363 were positive for HTLV on both EIAs (135 per 10(5), 95% CI 122-150). Prevalence differed considerably by region, from 83 to 222 per 10(5). Overall incidence rate was 3.6/10(5) person-years and residual transfusion risk was 5.0/10(6) per blood unit transfused. The logistic regression model showed significant associations with: age [adjusted odds ratio (aOR)=5.23 for age 50+ vs. <20], female sex (aOR=1.97), black (aOR=2.70 vs. white), and mixed skin colors (aOR=1.78 vs. white), and inversely with education (aOR=0.49, college vs. less than high school). HTLV testing with a dual-EIA strategy is feasible and can be useful in areas with low resources. Incidence and residual risk of HTLV-1 transmission by transfusion were relatively high and could be reduced by improving donor recruitment and selection in high prevalence areas. Blood center data may contribute to surveillance for HTLV infection.

The National Heart, Lung, and Blood Institute retrovirus epidemiology donor studies (Retrovirus Epidemiology Donor Study and Retrovirus Epidemiology Donor Study-II): twenty years of research to advance blood product safety and availability

The Retrovirus Epidemiology Donor Study (REDS), conducted from 1989 to 2001, and the REDS-II, conducted from 2004 to 2012, were National Heart, Lung, and Blood Institute-funded, multicenter programs focused on improving blood safety and availability in the United States. The REDS-II also included international study sites in Brazil and China. The 3 major research domains of REDS/REDS-II have been infectious disease risk evaluation, blood donation availability, and blood donor characterization. Both programs have made significant contributions to transfusion medicine research methodology by the use of mathematical modeling, large-scale donor surveys, innovative methods of repository sample storage, and establishing an infrastructure that responded to potential emerging blood safety threats such as xenotropic murine leukemia virus-related virus. Blood safety studies have included protocols evaluating epidemiologic and/or laboratory aspects of human immunodeficiency virus, human T-lymphotropic virus 1/2, hepatitis C virus, hepatitis B virus, West Nile virus, cytomegalovirus, human herpesvirus 8, parvovirus B19, malaria, Creutzfeldt-Jakob disease, influenza, and Trypanosoma cruzi infections. Other analyses have characterized blood donor demographics, motivations to donate, factors influencing donor return, behavioral risk factors, donors' perception of the blood donation screening process, and aspects of donor deferral. In REDS-II, 2 large-scale blood donor protocols examined iron deficiency in donors and the prevalence of leukocyte antibodies. This review describes the major study results from over 150 peer-reviewed articles published by these 2 REDS programs. In 2011, a new 7-year program, the Recipient Epidemiology and Donor Evaluation Study-III, was launched. The Recipient Epidemiology and Donor Evaluation Study-III expands beyond donor-based research to include studies of blood transfusion recipients in the hospital setting and adds a third country, South Africa, to the international program.

Human immunodeficiency virus prevalence, incidence, and residual risk of transmission by transfusions at Retrovirus Epidemiology Donor Study-II blood centers in Brazil

BACKGROUND

In Brazil nationally representative donor data are limited on human immunodeficiency virus (HIV) prevalence, incidence, and residual transfusion risk. The objective of this study was to analyze HIV data obtained over 24 months by the Retrovirus Epidemiology Donor Study-II program in Brazil.

STUDY DESIGN AND METHODS

Donations reactive to third- and fourth-generation immunoassays (IAs) were further confirmed by a less-sensitive (LS) IA algorithm and Western blot (WB). Incidence was calculated for first-time (FT) donors using the LS-EIA results and for repeat donors with a model developed to include all donors with a previous negative donation. Residual risk was projected by multiplying composite FT and repeat donor incidence rates by HIV marker-negative infectious window periods.

RESULTS

HIV prevalence among FT donors was 92.2/10(5) donations. FT and repeat donor and composite incidences were 38.5 (95% confidence interval [CI], 25.6-51.4), 22.5 (95% CI, 17.6-28.0), and 27.5 (95% CI, 22.0-33.0) per 100,000 person-years, respectively. Male and community donors had higher prevalence and incidence rates than female and replacement donors. The estimated residual risk of HIV transfusion transmission was 11.3 per 10(6) donations (95% CI, 8.4-14.2), which could be reduced to 4.2 per 10(6) donations (95% CI, 3.2-5.2) by use of individual-donation nucleic acid testing (NAT).

CONCLUSION

The incidence and residual transfusion risk of HIV infection are relatively high in Brazil. Implementation of NAT will not be sufficient to decrease transmission rates to levels seen in the United States or Europe; therefore, other measures focused on decreasing donations by at-risk individuals are also necessary.

Vasovagal reactions in whole blood donors at three REDS-II blood centers in Brazil

BACKGROUND

In Brazil little is known about adverse reactions during donation and the donor characteristics that may be associated with such events. Donors are offered snacks and fluids before donating and are required to consume a light meal after donation. For these reasons the frequency of reactions may be different than those observed in other countries.

STUDY DESIGN AND METHODS

A cross-sectional study was conducted of eligible whole blood donors at three large blood centers located in Brazil between July 2007 and December 2009. Vasovagal reactions (VVRs) along with donor demographic and biometric data were collected. Reactions were defined as any presyncopal or syncopal event during the donation process. Multivariable logistic regression was performed to identify predictors of VVRs.

RESULTS

Of 724,861 donor presentations, 16,129 (2.2%) VVRs were recorded. Rates varied substantially between the three centers: 53, 290, and 381 per 10,000 donations in Recife, São Paulo, and Belo Horizonte, respectively. Although the reaction rates varied, the donor characteristics associated with VVRs were similar (younger age [18-29 years], replacement donors, first-time donors, low estimated blood volume [EBV]). In multivariable analysis controlling for differences between the donor populations in each city younger age, first-time donor status, and lower EBV were the factors most associated with reactions.

CONCLUSION

Factors associated with VVRs in other locations are also evident in Brazil. The difference in VVR rates between the three centers might be due to different procedures for identifying and reporting the reactions. Potential interventions to reduce the risk of reactions in Brazil should be considered.

Interdonation intervals and patterns of return among blood donors in Brazil

BACKGROUND

In Brazil, most donations come from repeat donors, but there are little data on return behavior of donors.

STUDY DESIGN AND METHODS

Donors who made at least one whole blood donation in 2007 were followed for 2 years using a large multicenter research database. Donation frequency, interdonation intervals, and their association with donor demographics, status, and type of donation were examined among three large blood centers in Brazil, two in the southeast and one in the northeast.

RESULTS

In 2007, of 306,770 allogeneic donations, 38.9% came from 95,127 first-time donors and 61.1% from 149,664 repeat donors. Through December 31, 2009, a total of 28.1% of first-time donors and 56.5% of repeat donors had donated again. Overall, the median interdonation interval was approximately 6 months. Among men it was 182 and 171 days for first-time and repeat donors, and among women, 212 and 200 days. Predictors of return behavior among first-time donors were male sex (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.13-1.20), community donation (OR, 2.26; 95% CI, 2.20-2.33), and age 24 years or less (OR, 0.62-0.89 for donors ≥ 25 years). Among repeat donors predictors were male sex (OR, 1.35; 95% CI, 1.32-1.39), age 35 years or more (OR, 1.08-1.18 vs. ≤ 24 years), and community donation (OR, 2.39; 95% CI, 2.33-2.44). Differences in return by geographic region were evident with higher return rates in the northeast of Brazil.

CONCLUSION

These data highlight the need to develop improved communication strategies for first-time and replacement donors to convert them into repeat community donors.

Number of recent sexual partners among blood donors in Brazil: associations with donor demographics, donation characteristics, and infectious disease markers

BACKGROUND

Brazilian blood centers ask candidate blood donors about the number of sexual partners in the past 12 months. Candidates who report a number over the limit are deferred. We studied the implications of this practice on blood safety.

STUDY DESIGN AND METHODS

We analyzed demographic characteristics, number of heterosexual partners, and disease marker rates among 689,868 donations from three Brazilian centers between July 2007 and December 2009. Donors were grouped based on maximum number of partners allowed in the past 12 months for each center. Chi-square and logistic regression analysis were conducted to examine associations between demographic characteristics, number of sex partners, and individual and overall positive markers rates for human immunodeficiency virus (HIV), human T-lymphotropic virus Types 1 and 2, hepatitis B virus, hepatitis C virus, and syphilis.

RESULTS

First-time, younger, and more educated donors were associated with a higher number of recent sexual partners, as was male sex in São Paulo and Recife (p<0.001). Serologic markers for HIV and syphilis and overall were associated with multiple partners in São Paulo and Recife (p<0.001), but not in Belo Horizonte (p=0.05, p=0.94, and p=0.75, respectively). In logistic regression analysis, number of recent sexual partners was associated with positive serologic markers (adjusted odds ratio [AOR], 1.2-1.5), especially HIV (AOR, 1.9-4.4).

CONCLUSIONS

Number of recent heterosexual partners was associated with HIV positivity and overall rates of serologic markers of sexually transmitted infections. The association was not consistent across centers, making it difficult to define the best cutoff value. These findings suggest the use of recent heterosexual contacts as a potentially important deferral criterion to improve blood safety in Brazil.

Performance of parallel screening of Brazilian blood donors with two human immunodeficiency virus immunoassays: implications for sequential immunoassay testing algorithms in other countries

BACKGROUND

In Brazil it is mandatory to screen donors for human immunodeficiency virus (HIV) antibodies using two immunoassays (IAs) in parallel. Confirmatory testing is performed only on reactive donors who return for counseling. The goal of this analysis was to determine if concordant IA reactivity accurately predicts infection and can be used for HIV incidence and/or prevalence analyses.

STUDY DESIGN AND METHODS

We reviewed HIV screening and confirmatory results obtained for 307,407 donations in the first year of the REDS-II study in Brazil (2007) and for 2,304,755 donations collected from 1996 to 2006 in one of the REDS-II sites (São Paulo, Brazil).

RESULTS

In the São Paulo site, 11,410 (0.50%) HIV IA-reactive donations were discarded, but only 2095 (0.09%) were reactive to both IAs. Western blot was positive on 1002 (48%) dual-IA-reactive donors who returned for counseling. Only four HIV-infected donors were detected who had been missed at screening by one of the IAs; all occurred before 2002. The positive predictive value (PPV) of dual-IA reactivity varied from 45.8 to 100%, with 80% to 90% PPVs when using IAs from different manufacturers. If both assays yielded signal-to-cutoff (S/C) values of 3.0 or more, PPVs ranged from 91% to 99%, with approximately 99% sensitivity for true HIV seropositivity.

CONCLUSION

Parallel testing of all donations has limited efficacy when highly sensitive IAs are used. Reactivity by two sequential IAs is useful for prevalence studies if the assays are from different manufacturers and especially if high S/C values are considered.

Enhanced classification of Chagas serologic results and epidemiologic characteristics of seropositive donors at three large blood centers in Brazil

BACKGROUND

A major problem in Chagas disease donor screening is the high frequency of samples with inconclusive results. The objective of this study was to describe patterns of serologic results among donors to the three Brazilian REDS-II blood centers and correlate with epidemiologic characteristics.

STUDY DESIGN AND METHODS

The centers screened donor samples with one Trypanosoma cruzi lysate enzyme immunoassay (EIA). EIA-reactive samples were tested with a second lysate EIA, a recombinant-antigen based EIA, and an immunfluorescence assay. Based on the serologic results, samples were classified as confirmed positive (CP), probable positive (PP), possible other parasitic infection (POPI), and false positive (FP).

RESULTS

In 2007 to 2008, a total of 877 of 615,433 donations were discarded due to Chagas assay reactivity. The prevalences (95% confidence intervals [CIs]) among first-time donors for CP, PP, POPI, and FP patterns were 114 (99-129), 26 (19-34), 10 (5-14), and 96 (82-110) per 100,000 donations, respectively. CP and PP had similar patterns of prevalence when analyzed by age, sex, education, and location, suggesting that PP cases represent true T. cruzi infections; in contrast the demographics of donors with POPI were distinct and likely unrelated to Chagas disease. No CP cases were detected among 218,514 repeat donors followed for a total of 718,187 person-years.

CONCLUSION

We have proposed a classification algorithm that may have practical importance for donor counseling and epidemiologic analyses of T. cruzi-seroreactive donors. The absence of incident T. cruzi infections is reassuring with respect to risk of window phase infections within Brazil and travel-related infections in nonendemic countries such as the United States.