PCR-nucleic acid lateral flow immunoassay (NALFIA) with a product of direct multiplex PCR of a single Ostrea edulis larva. The label on the left side of every pair of cartridges is indicating the test line for the existence of O. edulis (FITC OE), Crassostrea gigas (632 CG), and Mytilus edulis (495 ME). The most upper line on the cartridges is indicating the control line of each NALFIA. The cartridge on the left side is showing the non-template control, and the following four cartridges are showing NALFIA replicates with a single larva of O. edulis each. The image of the 3% agarose gel electrophoresis is showing the quality control of the NALFIA. The scheme of the different gel slots: 1: 100 bp marker, 2: empty, 3: non-template replicate 1, 4: non-template replicate 2, 5: empty, 6: O. edulis larva replicate 1, 7: O. edulis larva replicate 2, 8: O. edulis larva replicate 3, 9: O. edulis larva replicate 4.