Donor Infectious Disease Testing Multinational assessment of blood-borne virus testing and transfusion safety on the African continent...

Abstract

BACKGROUND
Failures of blood screening due to low test quality or poor laboratory technique increase the
risk of transfusion-transmitted infections. For this reason, the World Health Organization has recommended a quality control (QC) system for African blood centers.

STUDY DESIGN AND METHODS
We conducted a cross-sectional research assessment of test performance at 51 blood centers in 17 African countries. A blinded, standardized panel containing 25 samples positive for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) and negative controls was tested by the centers using their operational infectious disease testing consisting of rapid tests, enzyme immunoassays (EIAs), or antigen- antibody EIAs. Nucleic acid testing was not performed.

RESULTS
The overall performances of the 42 assays were the lowest for hepatitis B surface antigen (75.6% sensitivity, 94.5% specificity), then for HCV (80.0% sen- sitivity, 98.1% specificity) and for HIV (81.4% sensitivity, 99.6% specificity). Poor sensitivity was driven by the use of rapid tests, which had sensitivities of 47.4% for HBV, 63.7% for HCV, and 72.4% for HIV. From a blood screening point of view, 321 (5.6%) infected units would have been transfused due to false-negative results. Assuming that those that were missed by rapid tests (84%) would have been detected by EIAs, 270 viral contaminations (92 HIV, 65 HCV, and 113 HBV) would have been avoided. 

CONCLUSION
These results support the discontinua- tion of rapid tests and implementation of antigen- antibody EIAs whenever possible in Africa. This successful QC program highlights the need for promoting such periodic external quality assessment studies. Transfusion-transmitted infections by viruses such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) are prevented by testing of blood products throughout the world. Paradoxically, high-income countries, where the prevalence of these pathogens is low, have the most comprehensive screening systems, while other countries, where the prevalence is the highest, have the worst systems.1 In consequence, the risk of transfusion-transmitted infection has become very low in the former2,3 while remaining high in the latter, particularly in sub- Saharan Africa.4 The same sub-Saharan African countries with the highest red blood cell requirements for anemic children and women are those which have not yet achieved robust and regular volunteer donor recruitment and cannot reduce the risk of transfusiontransmitted agents by expensive nucleic acid testing (NAT). Moreover, countries that depend on antibody or antigen screening assays are challenged by the relatively high cost of these tests, the difficulty in maintaining the cold chain, and a shortage of well-trained staff. This is significant, because failures of serologic screening due to low test quality or from poor laboratory expertise may adversely affect this otherwise cost-effective intervention.5 For this reason, the implementation of a quality control (QC) system has been recommended to the African Blood Centers by the World Health Organization (WHO), but has not yet been broadly implemented. A newly formed network of African blood transfusion specialists has therefore decided to perform a baseline evaluation of serologic testing performance. Building on the experience of a pilot study,6 the group now reports a QC study involving 51 blood centers belonging to 17 African countries. The aims of this research study were:

1. to allow each participating blood center to benchmark its laboratory procedures and assays;
2. to identify the most frequent reasons for poor quality, to define a consensus strategy based on appropriate assays; and
3. to provide to the health authorities preliminary data on the feasibility of ongoing QC assessment.