5 U.S. Code § 6384 - Employment and benefits protection
(a) Any employee who takes leave under section 6382 for the intended purpose of the leave shall be entitled, upon return from such leave—
(1) to be restored by the employing agency to the position held by the employee when the leave commenced; or
(b) The taking of leave under section 6382 shall not result in the loss of any employment benefit accrued prior to the date on which the leave commenced.
(c) Except as otherwise provided by or under law, nothing in this section shall be construed to entitle any restored employee to—
(d) As a condition to restoration under subsection (a) for an employee who takes leave under section 6382 (a)(1)(D), the employing agency may have a uniformly applied practice or policy that requires each such employee to receive certification from the health care provider of the employee that the employee is able to resume work.
(e) Nothing in this section shall be construed to prohibit an employing agency from requiring an employee on leave under section 6382 to report periodically to the employing agency on the status and intention of the employee to return to work.