Accuracy of the Kato-Katz method and formalin-ether concentration technique for the diagnosis of Clonorchis sinensis,and implication for assessing drug efficacy

Background: clonorchiasis is a chronic neglected disease caused by a liver fluke,clonorchis sinensis. chemotherapy is the mainstay of control and treatment efficacy is usually determined by microscopic examination of fecal samples. we assessed the diagnostic accuracy of the kato-katz method and the formalin-ether concentration technique (fect) for c. sinensis diagnosis,and studied the effect of diagnostic approach on drug efficacy evaluation. methods. overall,74 individuals aged ≥18 years with a parasitological confirmed c. sinensis infection at baseline were re-examined 3 weeks after treatment. before and after treatment,two stool samples were obtained from each participant and each sample was subjected to triplicate kato-katz thick smears and a single fect examination. results: thirty-eight individuals were still positive for c. sinensis according to our diagnostic 'gold' standard (six kato-katz thick smears plus two fect). two fect had a significantly lower sensitivity than six kato-katz thick smears (44.7% versus 92.1%; p <0.001). examination of single kato-katz and single fect considerably overestimated cure rates. conclusions: in settings where molecular diagnostic assays are absent,multiple kato-katz thick smears should be examined for an accurate diagnosis of c. sinensis infection and for assessing drug efficacy against this liver fluke infection. © 2013 qian et al.; licensee biomed central ltd.