Tenn. Code Ann. § 33-6-422

If, after the hearing is waived or is completed and the court has completed its consideration of the evidence, including the certificates of the examining professionals, and any other information relevant to the mental condition of the defendant, the court finds probable cause to believe that the defendant is subject to care and treatment under § 33-6-502, and that if involuntary treatment is not continued the defendant's condition resulting from mental illness or serious emotional disturbance is likely to deteriorate rapidly to the point that the defendant would be again admissible under § 33-6-403, the court may order the defendant held for care and treatment pending a hearing under chapter 6, part 5 of this title, for not more than fifteen (15) days after the probable cause hearing unless a complaint is filed under chapter 6, part 5 of this title, within the fifteen (15) days.