**4. Conclusions**

Today, CBA-N2a is widely used for the detection of CTXs in a variety of biological samples, other than fish, including *Gambierdiscus* cells [46,59,64,65,79,91,93,136], giant clams [59,137], gastropods [77], sea urchins [46,78], lobsters and crabs [61], sharks [103] and even samples derived from passive monitoring sampling devices [138–140], highlighting the benefit of incorporating this functional assay into routine ciguatera risk monitoring programs for increased food security of populations worldwide. However, due to the lack of a validated reference detection method, this toxin group is still unregulated. Owing to the good performance of this revisited CBA-N2a, this improved method could reasonably be regarded as a first step towards the implementation of a reference functional detection test, provided its further validation through inter-laboratory studies. To this end, significant progress needs to be achieved in addressing several other issues such as the current shortage of certified standards and reference materials as well as the lack of consensus extraction protocols.

#### **5. Materials and Methods**
