External quality assessment of national public health laboratories in Africa, 2002-2009

Abstract

OBJECTIVE: To describe findings from an external quality assessment programme involving laboratories in Africa that routinely investigate epidemic-prone diseases. METHODS: Beginning in 2002, the Regional Office for Africa of the World Health Organization (WHO) invited national public health laboratories and related facilities in Africa to participate in the programme. Three surveys comprising specimens and questionnaires associated with bacterial enteric diseases, bacterial meningitis, plague, tuberculosis and malaria were sent annually to test participants' diagnostic proficiency. Identical surveys were sent to referee laboratories for quality control. Materials were prepared, packaged and shipped in accordance with standard protocols. Findings and reports were due within 30 days. Key methodological decisions and test results were categorized as acceptable or unacceptable on the basis of consensus feedback from referees, using established grading schemes. FINDINGS: Between 2002 and 2009, participation increased from 30 to 48 Member States of the WHO and from 39 to 78 laboratories. Each survey was returned by 64-93% of participants. Mean turnaround time was 25.9 days. For bacterial enteric diseases and meningitis components, bacterial identification was acceptable in 65% and 69% of challenges, respectively, but serotyping and antibiotic susceptibility testing and reporting were frequently unacceptable. Microscopy was acceptable for 73% of plague challenges. Tuberculosis microscopy was satisfactorily performed, with 87% of responses receiving acceptable scores. In the malaria component, 82% of responses received acceptable scores for species identification but only 51% of parasite quantitation scores were acceptable. CONCLUSION: The external quality assessment programme consistently identified certain functional deficiencies requiring strengthening that were present in African public health microbiology laboratories.