(a) An employing agency may require that a request for leave under subparagraph (C) or (D) of section 6382(a)(1) be supported by certification issued by the health care provider of the employee or of the son, daughter, spouse, or parent of the employee, as appropriate. The employee shall provide, in a timely manner, a copy of such certification to the employing agency.

(b) A certification provided under subsection (a) shall be sufficient if it states—

(1) the date on which the serious health condition commenced;

(2) the probable duration of the condition;

(3) the appropriate medical facts within the knowledge of the health care provider regarding the condition;

(4)

(A) for purposes of leave under section 6382(a)(1)(C), a statement that the employee is needed to care for the son, daughter, spouse, or parent, and an estimate of the amount of time that such employee is needed to care for such son, daughter, spouse, or parent; and

(B) for purposes of leave under section 6382(a)(1)(D), a statement that the employee is unable to perform the functions of the position of the employee; and

(5) in the case of certification for intermittent leave, or leave on a reduced leave schedule, for planned medical treatment, the dates on which such treatment is expected to be given and the duration of such treatment.

(c)

(1) In any case in which the employing agency has reason to doubt the validity of the certification provided under subsection (a) for leave under subparagraph (C) or (D) of section 6382(a)(1), the employing agency may require, at the expense of the agency, that the employee obtain the opinion of a second health care provider designated or approved by the employing agency concerning any information certified under subsection (b) for such leave.

(2) Any health care provider designated or approved under paragraph (1) shall not be employed on a regular basis by the employing agency.

(d)

(1) In any case in which the second opinion described in subsection (c) differs from the original certification provided under subsection (a), the employing agency may require, at the expense of the agency, that the employee obtain the opinion of a third health care provider designated or approved jointly by the employing agency and the employee concerning the information certified under subsection (b).

(2) The opinion of the third health care provider concerning the information certified under subsection (b) shall be considered to be final and shall be binding on the employing agency and the employee.

(e) The employing agency may require, at the expense of the agency, that the employee obtain subsequent recertifications on a reasonable basis.

(f) An employing agency may require that a request for leave under paragraph (1)(E) or (3) of section 6382(a) be supported by a certification issued at such time and in such manner as the Office of Personnel Management may by regulation prescribe.