Journal Article

Are rapid diagnostic tests more accurate in diagnosis of plasmodium falciparum malaria compared to microscopy at rural health centres?

Nuwaha, Fred, Batwala, Vincent, Magnussen, Pascal

2010

Overview

Background Prompt, accurate diagnosis and treatment with artemisinin combination therapy remains vital to current malaria control. Blood film microscopy the current standard test for diagnosis of malaria has several limitations that necessitate field evaluation of alternative diagnostic methods especially in low income countries of sub-Saharan Africa where malaria is endemic. Methods The accuracy of axillary temperature, health centre (HC) microscopy, expert microscopy and a HRP2-based rapid diagnostic test (Paracheck) was compared in predicting malaria infection using polymerase chain reaction (PCR) as the gold standard. Three hundred patients with a clinical suspicion of malaria based on fever and or history of fever from a low and high transmission setting in Uganda were consecutively enrolled and provided blood samples for all tests. Accuracy of each test was calculated overall with 95% confidence interval and then adjusted for age-groups and level of transmission intensity using a stratified analysis. The endpoints were: sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). This study is registered with Clinicaltrials.gov, NCT00565071. Results Of the 300 patients, 88(29.3%) had fever, 56(18.7%) were positive by HC microscopy, 47(15.7%) by expert microscopy, 110(36.7%) by Paracheck and 89(29.7%) by PCR. The overall sensitivity >90% was only shown by Paracheck 91.0% [95%CI: 83.1-96.0]. The sensitivity of expert microscopy was 46%, similar to HC microscopy. The superior sensitivity of Paracheck compared to microscopy was maintained when data was stratified for transmission intensity and age. The overall specificity rates were: Paracheck 86.3% [95%CI: 80.9-90.6], HC microscopy 93.4% [95%CI: 89.1-96.3] and expert microscopy 97.2% [95%CI: 93.9-98.9]. The NPV >90% was shown by Paracheck 95.8% [95%CI: 91.9-98.2]. The overall PPV was <88% for all methods. Conclusion The HRP2-based RDT has shown superior sensitivity compared to microscopy in diagnosis of malaria and may be more suitable for screening of malaria infection.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Accuracy / Adolescent / Adult / Aged / Aged, 80 and over / Artemisinin / Biomedical and Life Sciences / Biomedicine / Blood / Care and treatment / Child / Child, Preschool / Control / Deoxyribonucleic acid / Developing Countries / Diagnosis / Diagnostic tests / DNA / Entomology / Female / Fever / Health aspects / Health facilities / Human diseases / Humans / Immunoassay - methods / Infant / Infectious Diseases / Laboratories / Low income areas / Malaria / Malaria, Falciparum - diagnosis / Male / Methods / Microbiology / Microscope and microscopy / Microscopy / Microscopy - methods / Middle Aged / Nucleotide sequence / Nurses / Parasites / Parasitology / Parasitology - methods / Patients / PCR / Physiological aspects / Plasmodium falciparum / Plasmodium falciparum - isolation & purification / Polymerase chain reaction / Predictive Value of Tests / Prospective Studies / Public Health / Quality control / Ribosomal DNA / Rural Health / Sensitivity and Specificity / Specificity / Stains & staining / Teaching hospitals / Tropical Medicine / Uganda / Vector-borne diseases / Young Adult