Periodic medical monitoring is sometimes required for job positions that deal with public safety.  For example, police officers and firefighters may be required to pass an annual medical examination.  This is the exception to the rule; in most cases employers can not require periodic medical monitoring.

An employer may require an employee who has completed alcohol rehabilitation to be periodically tested for alcohol if the employer has  reasonable belief that the employee will pose a direct threat without testing

Employee Assistance Program (EAP) counselors may ask employees about physical and mental conditions if the EAP counselor does not work for the employee's employer.  EAP counselors must keep confidential any information revealed by employees.  EAP counselors have no power over employment decisions.

There are other federal laws that require an employer to make disability-related inquiries and that may require employees to complete a medical evaluation.  Compliance with these laws does not violate the ADA.

Disability-related inquiries and medical examinations that are part of a voluntary wellness program do not violate the ADA.  A wellness program is voluntary if employers do not require participation and do not penalize employees for not participating.

For affirmative action purposes, employers may ask employees to voluntarily self-identify as persons with disabilities.