Example of false-positive PCR-nucleic acid lateral flow immunoassay (NALFIA) with a combination of three primer pairs and two DNA templates in combinations of Ostrea edulis, Crassostrea gigas, and Mytilus edulis. The NALFIA for the negative control, O. edulis / C. gigas and O. edulis / M. edulis DNA templates, respectively, shows the expected results and are supported by the gel electrophoresis with the expected bands of the negative control on lane 3, lane 4, O. edulis / C. gigas DNA on lane 6, lane 7 and O. edulis / M. edulis DNA on lane 9, lane 10. Nevertheless, the NALFIA for C. gigas / M. edulis shows a false-positive result for O. edulis, but with no visible band for O. edulis on the gel electrophoresis expected at 191 bp.