Accuracy of malaria rapid diagnostic tests in community studies and their impact on treatment of malaria in an area with declining malaria burden in north-eastern Tanzania

Malaria Journal

Research

Thor G Theander¹  Ib C Bygbjerg¹  Pamela Magistrado¹  Michael Alifrangis¹  Bruno P Mmbando²  John PA Lusingu²  Martha M Lemnge²  Deus S Ishengoma²  Filbert Francis² 

[1] Centre for Medical Parasitology at the Department of International Health, Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Denmark;National Institute for Medical Research, Tanga Medical Research Centre, P.O Box 5004, Tanga, Tanzania;

关键词: Malaria;    Malaria Parasite;    Parasite Density;    Artemisinin Combination Therapy;    Malaria Diagnosis;   

DOI  :  10.1186/1475-2875-10-176

 received in 2011-03-25, accepted in 2011-06-26,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundDespite some problems related to accuracy and applicability of malaria rapid diagnostic tests (RDTs), they are currently the best option in areas with limited laboratory services for improving case management through parasitological diagnosis and reducing over-treatment. This study was conducted in areas with declining malaria burden to assess; 1) the accuracy of RDTs when used at different community settings, 2) the impact of using RDTs on anti-malarial dispensing by community-owned resource persons (CORPs) and 3) adherence of CORPs to treatment guidelines by providing treatment based on RDT results.MethodsData were obtained from: 1) a longitudinal study of passive case detection of fevers using CORPs in six villages in Korogwe; and 2) cross-sectional surveys (CSS) in six villages of Korogwe and Muheza districts, north-eastern, Tanzania. Performance of RDTs was compared with microscopy as a gold standard, and factors affecting their accuracy were explored using a multivariate logistic regression model.ResultsOverall sensitivity and specificity of RDTs in the longitudinal study (of 23,793 febrile cases; 18,154 with microscopy and RDTs results) were 88.6% and 88.2%, respectively. In the CSS, the sensitivity was significantly lower (63.4%; χ2 = 367.7, p < 0.001), while the specificity was significantly higher (94.3%; χ2 = 143.1, p < 0.001) when compared to the longitudinal study. As determinants of sensitivity of RDTs in both studies, parasite density of < 200 asexual parasites/μl was significantly associated with high risk of false negative RDTs (OR≥16.60, p < 0.001), while the risk of false negative test was significantly lower among cases with fever (axillary temperature ≥37.5°C) (OR ≤ 0.63, p ≤ 0.027). The risk of false positive RDT (as a determinant of specificity) was significantly higher in cases with fever compared to afebrile cases (OR≥2.40, p < 0.001). Using RDTs reduced anti-malarials dispensing from 98.9% to 32.1% in cases aged ≥5 years.ConclusionAlthough RDTs had low sensitivity and specificity, which varied widely depending on fever and parasite density, using RDTs reduced over-treatment with anti-malarials significantly. Thus, with declining malaria prevalence, RDTs will potentially identify majority of febrile cases with parasites and lead to improved management of malaria and non-malaria fevers.

【 授权许可】

CC BY   
© Ishengoma et al; licensee BioMed Central Ltd. 2011