Under the federal Family and Medical Leave Act (FMLA), which covers employers with 50 or more employees, eligible employees have the right to substitute sick days for any part of a leave taken because of their own serious health condition or to care for a spouse, child, or parent. The FMLA does not supersede state laws if they give greater leave rights to employees. Employers covered by both laws should carefully review the various provisions of both to make sure that employees receive the full benefits of both laws.
Furthermore, the Americans with Disabilities Act (ADA) states that allowing the use of accrued paid leave, or unpaid leave, is a form of reasonable accommodation when necessitated by an employee's disability. Employers should be aware of the interaction between the two federal laws.