The Davidson County Medical Coroner in Tennessee told RadarOnline.com that the results are expected in up to 12 weeks.
"The body remains here with us, and additional testing is required to determine the cause of death," an official told RadarOnline.com.
According to the Nashville Police Department, a close friend of McKeehan discovered his body at the his Nashville home early Wednesday morning, October 23. He was pronounced dead at the scene.
"No foul play was suspected," police revealed.
TobyMac, also known as Kevin Michael McKeehan, postponed the remaining dates of a week-long Canadian tour to return home to his wife and other children in Franklin, Tennessee.
In a statement, TobyMac said his son "had joy that took the room when he entered."
"He was a magnetic son and brother and friend. If you met him you knew him, you remembered him. His smile, his laugh, the encouragement he offered with words or even without. He had an untamable grand personality and dreams to match."
Truett had been following in his father's footsteps, and was an aspiring Christian rapper.
He went by the names Truett Foster, TRU, Shiloh and truDog online and collaborated with his father on a few tracks.