Improving the safety of the blood supply in Ecuador through external performance evaluation of serological screening of blood donors

Abstract

Background: The Ecuadorian National Blood System collects approximately 100 000 units of blood per year. Screening for infectiousagents is conducted by 23 autonomous blood services using different methodologies and reagents. Objectives: To evaluate the performanceof serology testing by laboratories of the Ecuadorian National Blood Bank System. Study design: Four proficiency panels were distributed between April 2003 and December 2004 containing samples that were characterized as either reactive or non-reactive for hepatitis B surface antigen (HBsAg), antibodies against hepatitis C virus (HCV), and antibodies against human immunodeficiency virus (HIV). Laboratories were classified according to the volume of blood units processed per year, as small (<5000), medium (5000–12000) and large (>12000). Results: Large and medium blood services consistently obtained better results than small ones. All of the 37 anti-HIVantibody false negative results and all of the 20 HBsAg false negative results were reported by small laboratories. False negative results were associated with the use of rapid tests. Laboratories using rapid tests and certain lots of an enzyme-linked immunosorbent assay (ELISA) failed to detect HCV reactive sera in December 2004. Conclusion: The high number of incorrect results in most small blood services indicates serious weaknesses in blood screening that require urgent corrective action. The National Blood System has implemented on-site audits, training, technical assistance, and increased oversight. The long-term proposal is to centralize blood testing in two large blood centers. The results presented here underline the importance of strengthening the regulatory framework and oversight in Ecuador and highlight the role of external performance evaluation programs for blood safety improvement.