Therapists usually refer you to someone who does cognitive assessments, if that's seen as important in shaping how your psychotherapy is to be done, then use the results, the way they would use results of medical tests.

A social worker isn't trained to do this even if she wanted to. Same with a psychoanalyst. Psychiatrist don't usually do this either. Psychologist can and some do, though many who work as regular therapists don't do this either. In other words, if the psychologist works in a cognitive rehab facility or something, then he might do this regularly but if you go to go to the average therapist to help you with depression or anxiety or PTSD, it's quite unlikely that they themselves would administer a WAIS to you.

Everything here in all subforums is related in some ways, given that it's a psych forum, but this thread is not particularly relevant to the psychotherapy subforum. Then again I've seen other irrelevant threads take forever to be moved elsewhere.