As defined by ISO 10993-17, the following process can be used to establish standardized acceptable exposure levels, and can also be used to limit exposure to remain within acceptable levels. The process steps are:
- Identify the critical health endpoint (the lowest acceptable level of exposure) through literature review.
- Determine a point of departure, typically the highest level of exposure at which no adverse effects occur (NOAEL).
- Examine the route and duration of exposure to create a Tolerable Intake level (TI).
- Calculate a Tolerable Exposure (TE) for patient subgroups.
- Where feasible, calculate the TE as a function of potential benefit of device usage.
- Compare the final TE with worst-case exposure levels and calculate a Margin of Safety (MOS).