The routine activity of analyzing oil properties and suspended contaminants for the purpose of monitoring and reporting timely, meaningful and accurate information on oil and machine condition.

Particle counting is probably one of the best tests there is for maintaining system cleanliness. The point of contention lies with whether or not particle count is an appropriate test for all fluid types and systems. Whilst it is an excellent method for determining the number and size of particles being generated, particle counting won't tell you what the particles are. They could be metallic – both ferrous and non-ferrous – silica (dirt, dust), silt, filter fibres, bacteria colonies, varnish agglomerations, water, etc. Therefore, the decision to do particle count Oil testing should be based on the type of information you want to collect.