Currently, the “gold standard” diagnostic for OV infection is the formalin ethyl-acetate concentration technique (FECT), which quantifies OV eggs in feces. The FECT method has several
important drawbacks, including limited analytical sensitivity (A-Sn): i.e., light intensity infections can go undetected, requiring extensive fecal sampling over the course of days, which can be logistically onerous (if not impossible) in the resource limited settings where OV transmission is currently occurring. In addition, FECT has been shown in several studies [8] to have a limited analytical specificity (A-Sp), with OV eggs often confused with the eggs from minuteintestinal flukes infection (MIFs) and accurate distinction, requires the presence of an experienced microscopist [9, 10]. Finally, advanced hepatobiliary pathologies from chronic
opisthorchiasis such as biliary tract obstruction from bile duct fibrosis or primary biliary sclerosis, can obstruct the flow of eggs into the lumen and hence into feces, making the detection of light OV infection by coprological method nearly impossible [11]. Together, these limitations decrease the utility of FECT where OV transmission occurs in the Mekong Basin Region [8].