Each employee of the State of Georgia or of any branch, department, board, bureau, or commission of the State of Georgia who donates one of such employee's kidneys for the purpose of transplantation shall receive a leave of absence, with pay, of 30 days and such leave shall not be charged against or deducted from any annual or sick leave and shall be included as service in computing any retirement or pension benefits. The employee shall not be entitled to such leave of absence with pay unless he furnishes to his supervisor or other proper authority a statement from a medical practitioner who is to perform such transplantation procedure or from a hospital administrator that the employee is making a kidney donation as provided in this Code section. If such donation does not occur, the provisions of this Code section shall not be applicable.