[Value of rapid tests for diagnosis of malaria in Benin]

Reliable diagnosis of malaria is essential in malaria endemic areas. The purpose of this study was to compare the performance of rapid diagnostic tests to that of the thick and thin blood smear techniques conventionally used for diagnosis of malaria. A total of 84 patients presenting malaria symptoms were included and tested for malaria. Results of blood smears and rapid tests performed blindly in external labs were compared with results of blood smears and PCR done in our reference laboratory. Sensitivity, specificity, positive and negative predictive value were determined using PCR as the gold standard. Results of the rapid diagnostic test were much better than those of the microscopic technique performed in external labs, particularly with regard to true positivity. The blood smear technique in external labs led to 12 false positive diagnoses and was associated with a lower positive predictive value than the rapid test: 58.6% vs. 85.7%. The sensitivity and specificity of the rapid test were also higher than those obtained in external laboratories using blood smear techniques: 90.0% and 95.3% respectively versus 85.0% and 81.2% respectively. The results of this study indicate that the rapid test is more reliable than microscopy and that its use would improve malaria diagnosis. Risks factors for false diagnosis and limitations of the different diagnostic techniques are discussed.