The International Phytoplankton Intercomparison (IPI) is an international partnership to provide enumeration and identification quality assurance in marine phytoplankton. It was formerly part of the now concluded EU initiative Biological Effects Quality Assurance in Monitoring Programmes (BEQUALM). The IPI is implementing its intercomparison exercises through the Marine Institute Ireland in cooperation with the Intergovernmental Oceanographic Commission of UNESCO (IOC) through its Science and Communication Centre on Harmful Algae at the University of Copenhagen, Denmark. The IPI operates according to the ISO standards 17043 Conformity assessment-General requirements for proficiency testing and ISO13528 Statistical methods for use in proficiency testing by interlaboratory comparisons. We are currently applying for accreditation for 2017 under ISO17043 to the Irish national Accreditation Board (INAB) for the IPI to be accredited as a proficiency testing scheme. Also, as part of this push towards accreditation, the Marine Institute have sanctioned a Lab attendant position to help with the organization of the exercise, production of materials, methodology improvements and working on a document control system for the accredited process. These changes are essential for the continuation of the scheme and in order to attain the accreditation under ISO17043. The IPI will have a board consisting of representatives of the Marine Institute and IOC UNESCO. These members can invite additional partners to be represented on the board. The IPI management of finances and payments is via the Marine Institute, Ireland. At present, the main parameters measured under the IPI exercise are the composition and abundance of marine phytoplankton in preserved marine water samples. We are studying the possibility of including biovolume and carbon content calculation to the scheme as a measure of biomass which may be needed in the future for some laboratories working under the Water Framework Directive (WFD) rules. The water quality EN documents EN14996, Water quality - Guidance on assuring the quality of biological and ecological assessments in the aquatic environment and EN 15204, Water quality - Guidance standard for the routine analysis of phytoplankton abundance and composition using inverted microscopy (Utermöhl technique) do not include how to estimate biovolume in water. That’s why the CEN/TC 230 (WP7) draft guidance document was developed in 2014; a European standard on the estimation of algal biovolume as a development and improvement of standards in support of the WFD. It describes a general procedure for the determination or estimation of biovolume of marine and freshwater phytoplankton taxa using the inverted microscopy (Utermöhl technique). The determination of phytoplankton abundance and composition according to EN 15204 is a precondition for the calculation of the biovolume of a phytoplankton samples. It makes sense for us to include this measurement as we already fulfill this pre-condition (abundance and composition), so it would be easy to add a measure of biovolume to those participants that may require it. There would be an additional fee for this add-on to the scheme for those participants that would like to participate in the biovolume part of the exercise. We are proposing to collaborate with Aquaecology an environmental agency based in Germany as they have already carried out a biovolume exercise in 2014 and they have an online system already in place for the calculation of biovolume. This also could attract more participants to our scheme from laboratories already participating in the biovolume exercise with Aquaecology. Partnerships: The IPI is a partnership of agencies, quality control entities and organizations with interest in phytoplankton monitoring and quality control. Partnership will allow for endorsement on IPI certificates of proficiency by national or regional partners where this will enhance the value of certificates to participants in the proficiency testing. The UK National Marine Biological Analytical Quality Control Scheme (NMBAQC) is one of these partners. They have been associated with the IPI scheme (formerly Bequalm) since the beginning in 2005 as the umbrella group for UK laboratories participating in community analysis intercomparison exercises.