The medical board shall complete a preliminary investigation of a complaint not later than the 30th day after the date of receiving the complaint. The medical board shall first determine whether the surgical assistant constitutes a continuing threat to the public welfare. On completion of the preliminary investigation, the medical board shall determine whether to officially proceed on the complaint. If the medical board fails to complete the preliminary investigation in the time required by this section, the medical board’s official investigation is considered to commence on that date.