High Incidence of False-Positive Malaria Rapid Diagnostic Tests in Ugandan Under-5s
Overview
This study found a 10.7% prevalence of false-positive malaria rapid diagnostic tests (mRDTs) among Ugandan children under five, strongly linked to regional malaria transmission intensity. False-positive results were more common in children with recent fever, antimalarial use, and anemia, potentially leading to overestimation of malaria prevalence and inappropriate treatment.
Background
Malaria rapid diagnostic tests (mRDTs) are widely used in Uganda for quick malaria diagnosis but can yield false-positive results due to persistent HRP-2 antigen after parasite clearance. While false-negative mRDTs have been extensively studied, the prevalence and impact of false-positive results remain less understood. False-positive mRDTs can lead to misdiagnosis, unnecessary antimalarial use, and may hinder management of nonmalarial febrile illnesses, contributing to antimalarial resistance.
Data Highlights
Measure
Value
False-positive mRDT prevalence
10.7% (849/6786)
Prevalence difference with recent fever
+17.2% (95% CI: 13.7%, 20.6%)
Prevalence difference with recent antimalarial use
+14.7% (95% CI: 7.1%, 22.3%)
Prevalence difference with comorbid anemia
+8.1% (95% CI: 5.9%, 10.3%)
Prevalence difference with recent antibiotic use
-17.6% (95% CI: -22.5%, -12.7%)
Predictive model AUC
0.79 (weighted)
Key Findings
False-positive mRDTs occurred in 10.7% of microscopy-negative children under five in Uganda.
Higher false-positive rates were associated with recent fever, recent antimalarial treatment, and anemia.
False-positive prevalence correlated strongly with regional malaria transmission intensity.
Recent antibiotic use was associated with a lower prevalence of false-positive mRDTs.
A combined model using clinical, environmental, and household factors predicted false-positive mRDTs better than individual factor models (AUC=0.79).
Clinical Implications
Clinicians should be aware that positive mRDT results in children under five may not always indicate active malaria infection, especially in high transmission areas or following recent antimalarial treatment. Overreliance on mRDTs without confirmatory testing could lead to overtreatment and neglect of other febrile illnesses. Integrating clinical and environmental factors may improve diagnostic accuracy and guide appropriate treatment decisions.
Conclusion
False-positive malaria rapid diagnostic tests are common among Ugandan children under five and can distort malaria prevalence estimates and clinical management. Enhanced diagnostic strategies are needed to reduce misdiagnosis and optimize antimalarial use.
