Yes, if you approach the situation correctly. Be careful not to say anything that will lead to an ADA-AA claim that you suspected that the EE has some sort of disability. Also you have to be careful not to ask or pursue the general health condition of the employee.
What you can do is require a fitness for duty exam, but you are limited to the specific concern that triggers the fitness for duty exam. Send the employee, with a job description, to your medical provider with your concern. You may only inquire is the employee fit for duty or not fit for duty.
If you send an EE for a fitness for duty exam you must be able to do certain things:
- Be able to articulate observable behavior that will explain the need for the exam. ( substantial increase in errors; an accident; odor of alcohol; ETC)
- Be certain the EE understands that the exam is not meant for punishment.
- Be able to articulate a threat to health or safety to others
If the person is found to be unfit for duty then other sets of rules may come into play. Your sick leave policy; FMLA; ADA-AA; accommodations; Worker's Compensation could be a few.