Tried searching for this answer. Seen a lot of discussion about radon certification agencies and the InterNACHI “Advanced Radon Measurement Service Provider Course”.
It looks like for pre-licensing, at least according to the training, a test has to be ordered from NRSB and sent to the proctoring facility. I cannot find a clear answer for CE, however. Previously, I always did NRSB CE through a correspondence course that would have a graded exam, but no proctoring requirements.
I also sent a message to NRSB staff asking this, but hoping for a quick answer here. If I get a firm answer from NRSB, I will update this thread with the information.