Total radial runout and reference error

We have a workshop specializing in machining large shafts. We work according to ISO standards. We need to verify the geometric tolerance of total radial runout, and my question is as follows:

We always assume the reference of a geometrical tolerance to be perfect, but if the part we take as the reference has any form or positional error once machined, would this error add to the total radial runout we measure?

Thanks in advance.