Your employer may require that the need for leave based on your own or your immediate family member's serious health condition be supported by a certification issued by a health care provider. Your employer must allow you at least 15 calendar days to obtain the medical certification. The certification must include: a description of the serious health condition; the date that the condition began or treatment became necessary; and the expected duration of the condition or treatment. Your employer may, at its own expense, require you to obtain a second medical certification from a health care provider. Your employer may choose the health care provider for the second opinion, except that in most cases it cannot be someone with whom your employer regularly contracts or uses his or her services (not the "company doctor."). If the opinions of the two designated health care providers differ, your employer may require you to obtain certification from a third health care provider, again at the employer's expense. This third opinion shall be final and binding. The third health care provider must be approved jointly by you and your employer. In addition, your authorization is required for the release of medical information to second/third opinion health care providers. If it is requested by your employer and you don't provide the medical certification, your absence is not protected by the FMLA. This means that your employer has the legal right to fire you for that absence (unless some other law, or your collective bargaining agreement, applies).