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Suitability of commercially available POC-CCA tests for schistosomiasis: Considerations for efficiency, reproducibility and decision making criteria for field application in areas of low endemicity

Grenfell, Rafaella F.Q., Pedrosa, Maria Luysa, Couto, Flavia F.B., Almeida, Aureo, Coelho, Paulo Marcos Z., Katz, Naftale
Journal of immunological methods 2019 v.472 pp. 1-6
decision making, eggs, feces, indigenous species, schistosomiasis, urine
Point of care tests would be valuable for field diagnosis. However, high sensitivity will likely be required in low endemicity sets where individuals with low schistosome burden are hard to diagnose.Commercially available POC tests (POC-CCA® and Urine CCA (Schisto) ECO Teste®) were evaluated to evidence their potential in low endemicity areas. Individuals with 0–76 eggs per gram of feces were selected, and comparison was performed between Kato-Katz, Saline Gradient and POC-CCA® after urine concentration (POC FLT) methods.Both POC-CCA had poor performances, showing low identification of less than half of positive individuals and several undiagnosed cases, revealing an accuracy of 0.44 and 0.46, and a Kappa Index of 0.308 and 0, respectively. Positivity rates of POC-CCA tests were below the one found for a single Kato-Katz slide. POC FLT had a Kappa Index of 0.617, an accuracy of 0.81, 67% of reproducibility, and was shown to have the same sensitivity of 21 Kato-Katz slides when two tests were performed.POC-CCA® and POC Eco presented exactly the same inadequacy in low endemicity areas. POC FLT significantly improved the performance of POC-CCA®. More accurate methods must be evaluated in low endemicity areas.