Summation is required if the licensee is required to monitor for both external and internal doses.
The results of bioassays alone cannot be used to determine if the licensee must monitor internal exposures or sum internal and external dose under 10 CFR Part 20. Determination of what an individual is likely to receive is a prospective assessment of intake. Bioassay is a retrospective assessment of intake. Future intakes are not necessarily the same as past intakes. However, bioassay data may be used together with other information as a basis for the prospective intake assessment.