Improving the safety of the blood supply in Ecuador through external performance evaluation of serological screening of blood donors.
BACKGROUND
The Ecuadorian National Blood System collects approximately 100 000 units of blood per year. Screening for infectious agents is conducted by 23 autonomous blood services using different methodologies and reagents.


OBJECTIVE
To evaluate the performance of serology testing by laboratories of the Ecuadorian National Blood Bank System.


METHODS
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-HIV antibody 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.


CONCLUSIONS
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.
Grijalva
Mario J
MJ
Infectious Disease Research Laboratory, School of Biological Sciences, Catholic University, Quito, Ecuador. grijalva@ohio.edu
Chiriboga
Rosa F
RF
Vanhassel
Hans
H
Arcos-Teran
Laura
L
D001771:Blood Banks / Q000592:standards; D001782:Blood Donors; D004484:Ecuador; D005188:False Negative Reactions; D015483:HIV Antibodies / Q000097:blood*; D006679:HIV Seropositivity / Q000175:diagnosis*; D006509:Hepatitis B / Q000097:blood / Q000175:diagnosis*; D006510:Hepatitis B Antibodies / Q000097:blood*; D006526:Hepatitis C / Q000097:blood / Q000175:diagnosis*; D018937:Hepatitis C Antibodies / Q000097:blood*; D006801:Humans; D007753:Laboratories / Q000592:standards*; D011786:Quality Control; D012698:Serologic Tests
D015483:HIV Antibodies; D006510:Hepatitis B Antibodies; D018937:Hepatitis C Antibodies