This document describes the characteristics of working suspensions of nano-objects to be considered when conducting in vitro assays to evaluate inherent nano-object toxicity. In addition, the document identifies applicable measurement methods for these characteristics.

This document is applicable to nano-objects, and their aggregates and agglomerates greater than 100 nm.

This document intends to help clarify whether observed toxic effects come from tested nano-objects themselves or from uncontrolled sources.