After several years of intensive revision, the updated version of ISO 4407 has finally been released. This marks a real milestone for professionals working in microscopic particle analysis. The new edition of ISO 4407 is ready for the future – practical, open to new technologies, and fully aligned with modern quality processes.
Anyone working with microscopes knows it: ISO 4407 – the standard for manual particle counting on filter membranes. It serves as the counterpart to ISO 11171, which governs the calibration of automatic particle counters for liquids. But while ISO 11171 has undergone continuous updates and adjustments over the years, ISO 4407 remained largely unchanged since the 1980s – until now.
Time for an update – and it is finally here.
Sean Ball, a team member at PAMAS, took on the challenge. As the project lead, he invested significant dedication and technical expertise into a full modernization of ISO 4407. The result is a thoroughly revised standard that now includes not only manual particle counting but also automatic counting using modern imaging technology. Beyond digitizing the particle analysis process, the revision also includes major updates to sample preparation procedures and microscope calibration methods – all brought in line with the latest technological standards. These updates are essential for ensuring accuracy and comparability – both for microscope manufacturers and for users of the standard.
A feat of international teamwork
Bringing the revised standard to life was a major effort: The international committee ISO TC131/SC6/WG2 spent five years laying the groundwork to ensure ISO 4407 is both technically sound and future-ready. The committee has now approved the final draft of the standard, which was officially published December 2025.
With the new ISO 4407, users now have access to a modern, technically robust framework that not only meets current industry needs, but also provides room for future developments.
At PAMAS, we are proud to have played a part in this progress, and we are excited to see our expertise help shape the future of this established standard.
Interested in our microscopic particle analysis system?
Learn more about the PAMAS FastPatch 2 GO here.
