Rapid Diagnostic Tests for Malaria: A Review

摘要

Malaria remains one of the most important endemic disease threats facing the Canadian Forces during overseas deployment. The existing accepted gold-standard for diagnosing malaria is the microscopic examination of thick and thin blood smears. This method has the advantage of high sensitivity, quantifiable results, and accurate speciation, but is fairly time-consuming and requires well-trained microscopists in order to detect low parasitemias and to properly differentiate the species. Commercially available rapid diagnostic immunocapture test strips now exist which do not require the same level of training and equipment as microscopic examination, and are also significantly faster. However, as this review delineates, clinical trials have shown that the strips are not as sensitive as microscopic examination in detecting low level parasitemias, cannot quantify the level of malaria infection, and, at present, can only differentiate between falciparum and non-falciparum malaria. The strips also have problems relating to antigen persistence in the blood after parasite clearance from chemotherapy, leading to false positive post- therapeutic diagnoses. At present, the test strips are not approved by Health Canada and any use must be under appropriate clinical trial conditions. In addition, the test strips are currently not recommended to be used without a parallel blood smear sample being examined.