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

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.

Quality assessment of malaria laboratory diagnosis in South Africa.

To assess the quality of malaria diagnosis in 115 South African laboratories participating in the National Health Laboratory Service Parasitology External Quality Assessment Programme we reviewed the results from 7 surveys from January 2000 to August 2002. The mean percentage incorrect result rate was 13.8% (95% CI 11.3-16.9%), which is alarmingly high, with about 1 in 7 blood films being incorrectly interpreted. Most participants with incorrect blood film interpretations had acceptable Giemsa staining quality, indicating that there is less of a problem with staining technique than with blood film interpretation. Laboratories in provinces in which malaria is endemic did not necessarily perform better than those in non-endemic areas. The results clearly suggest that malaria laboratory diagnosis throughout South Africa needs strengthening by improving laboratory standardization and auditing, training, quality assurance and referral resources.