Figure 3. Reference Levels for Interpreting or Responding to Intake Monitoring Results

DOE-STD-1121-98

Is bioassay or air

monitoring datum...

Is intake

> LDV?

Record result

confirmed?

Yes

Use default

assumptions

Record

> DIL?

Calculate HE,50

and Report

Yes

Calculate HT,50

> LDMR?

Investigate

Yes

LDV

Derived Verification Level

Involve

DIL

Derived Investigation Level

Medical Staff

LDMR Derived Medical Referral Level

Figure 3. Reference Levels for Interpreting or Responding to Intake Monitoring Results

appropriate blank. Guidance from a variety of sources (including HPS N13.30-1996) uses the concept of

an appropriate blank for comparison with analytical measurements such as those that form the basis for

bioassay measurements. In fact, however, two distinct decisions are confounded by the current method:

the first is the decision whether radioactivity above background levels is present, and the second is a

decision whether any radioactivity that is present is above that which would be expected from non-

occupational exposures, as explained in the IDG. For example, it is well known that environmental

exposures to natural uranium occur, and that these have been mistaken for occupational exposures.