Abstract

Nouhoum Bouare,&, Jean Delwaide, Sebastien Bontems, Laurence Seidel and Christiane Gerard

To diagnose an HCV infection is expensive because it is important to know to what extent seropositive patient is or not, viremic. The study aimed to define the best combination of serological tools to use in order to get the best prediction for HCV viremia at cheaper cost. The study questions focused on: usefulness of repeat tests, relevance of EIA test ratio (TR) values, use of a confirmatory test or a second screening test, costs of these alternatives, and choosing the best option giving an excellent probability of HCV-RNA detection. Costs were calculated using estimates for each EIA test, LIA-HCV, and PCR. Global data from two epidemiological surveys carried out between 2009-2010 in Mali were used. By using as an indicator, the magnitude of the signal-to-cutoff ratio measured with EIA, PPV (Positive Predictive value) of the presence of HCV RNA significantly increased from 41.2% to 82.4%. The highest PPV was obtained by performing two 4th generation EIA tests and exploitation of the threshold (half of the maximal ratio value measured). The cost of additional tests for virus detection ranged between 3550 USD and 1155 USD, and the algorithm presenting the highest PPV (87.5%) was not the most expensive (1551 USD).