1. Skip to navigation
  2. Skip to content
  3. Skip to secondary content
  4. Skip to sidebar

Transfer of Receptor Binding Assay for Harmful Algal Toxins

Project Number: INT/7/015


To stimulate discussion on risk assessment, standard setting, and regulatory practice protocols; to establish a link with the Intergovernmental Oceanographic Commission (IOC) harmful algal blooms (HABs) web site; to facilitate a reliable and sustained supply of toxin standards and radiolabelled toxin required for the receptor binding assay (RBA) programme; to prepare quality assurance/quality control (QA/QC) procedures to be used for purifying saxitoxin (STX) and radiolabelled STX; and to adapt RBA to render it less susceptible to non-ideal laboratory conditions in order to be used in remote locations.


One of the most serious and visible problems facing coastal waters is related to the phenomena commonly known as red tide or HABs. HABs cause the entry of toxic substances into the human food chain.
One of the most significant manifestations of HABs is that certain algal species produce toxins that can accumulate in seafood products, thus posing a risk to human consumers. The effect on humans range from mild discomfort to debilitating long-term illnesses and even death. Paralytic shellfish poisoning (PSP) has the most significant impact on human health. Because of the risk to health, many countries monitor and regulate the levels of such toxins in shellfish, just as they do with the bacterial and viral contamination to which shellfish are also subject.
Regulation when HABs are present usually takes three forms: closure of commercial fisheries, warning to subsistence harvesters, and prohibitions on commercial trade in shellfish products. The mouse bioassay (MBA) is certified for this purpose by the Association of Official Analytical Chemists (AOAC) and is the method against which other methods are judged. While it is simple, rugged, and reliable, the method is neither inexpensive, rapid, nor sensitive.
Large sample loads require that mouse colonies numbering to the thousands be maintained accompanied by large space requirements and maintenance costs, even when no testing is being conducted. Moreover, the use of live animals for product testing is prohibited in many countries and will be discontinued in others. Reliable, rapid, sensitive, and accurate assays for toxins are a requirement for any legal regulatory framework. Standardization from country-to-country is needed for testing applied to goods traded in international commerce.
A key application of nuclear technologies that can circumvent the problems highlighted for the MBA is RBA. This method will ensure sustained and effective shellfish toxicity monitoring worldwide. The scope of the PSP problem ensures a significant impact of an interregional programme that encourages this change with the involvement of a large number of countries.

National Commitment:

The participating Member States will provide adequate laboratory facilities and personnel, and use the RBA technology in their national monitoring programmes.

Agency Input:

Support activity, supply of reagents, and expert missions; subcontracts, inter-laboratory QA/QC calibration exercises; and provision of information and modification of equipment.

Performance Indicators:

Number of Member States using QA/QC procedures provided.
Written protocols of regulatory practice including the use of RBA in national programmes.
Amount of purified radiolabelled STX produced.
Number of applications of modified radiometric detection and data acquisition hardware to be used in RBA development.
Number of publications in international refereed journals referring to RBA from participating institutions.

Expected Results:

Partner institutions will be interconnected via the IOC HABs web site. This interconnection will facilitate the sharing of education and technical resources related to HABs and their toxins. Established QA/QC procedures for purified STX and radiolabelled STX will provide consistency in testing. Regulatory practices will be revised identifying RBA as a reliable, rapid, sensitive, and accurate assays for detecting toxins in seafood.

Project Impact:

Strengthened monitoring and management strategies for HABs will increase the export of shellfish products and the income of commercial fisheries in the participating countries. The number of poisoning cases and deaths due to PSP will be reduced. Mitigation and elimination of HABs will contribute to national economies and sustainability of Member States.