I am having trouble finding up to date resources on Modifier AJ. My office is going to be hiring a social worker or drug counselor to do substance abuse therapy. I've discussed this w/ another local practice and they append the AJ modifier to everything done by anyone who is not a psychologist. When I looked it up in the CPT book the definition is "Clinical social worker." Can anyone tell me when exactly I would need to use it, if at all?? Thanks!