The NP is a licensed professional. He will first, administer the various tests, then score them. He will then have to interpret the scores within the guidelines of the published test standards. The only place an NP can be biased is in diagnosing causation. If your issue is about your level of function, not causation, you will be fine. If causation is an issue, then it can take a bit more effort to support an accurate diagnosis. Either way, I would not be concerned.