Sensitivity Concordance Between Rapid Diagnostic Tests and Thick Smears for Detecting Malaria at Sultan Cherif Kasser Hospital, N'Djamena Central Health District

Malaria is a parasitic infection transmitted to humans by insect bites. It remains the deadliest parasitic disease and is a major public health problem. The objective of this study was to evaluate the sensitivity of a rapid diagnostic test (RDT) compared to thick smear microscopy, considered the gold standard. Blood samples from 427 patients aged 1 to 86 years were examined using both RDTs and thick smears in the laboratory. Of the 427 participants, 382 had identical results, representing an overall concordance of 89.5%, including 182 (42.6%) true negatives (TS- RDT-) and 200 (46.8%) true positives (46.8%) (RDT+ and TS+). In 45 cases of overall discordance, the percentage was 10.5%, divided into 19 cases (4.4%) of false negatives (RDT- and TS+) and 26 (6.1%) of false positives (RDT+ and TS-). The most represented age group was 18–50 years, followed by 1–5 years. The sensitivity of the rapid diagnostic test (RDT) was 91.3%. The specificity of the RDT was 87.5%. The positive predictive value (PPV), representing the probability that a patient who tests positive is actually infected with malaria, was 88.5%, and the negative predictive value (NPV), indicating the probability that a patient who tests negative is actually uninfected, was 90.5%. RDTs and thick smears are diagnostic tools for malaria in Plasmodium patients and for assessing parasitemia in order to provide effective antimalarial treatment to patients. They are the main means of combating malaria. However, thick smears remain essential, particularly for quantifying parasitemia and identifying clinically suspected cases that may be negative on RDT.