Tennessee runs a TICS Tennessee Instant Check System check for state RKBA disqualifications (I call it active wants and warrants) that are not permanent disqualifications under NICS, then they are the point of contact for the federal NICS background check. All for $10.
(Aside): Why I would not give that up and go back to what there was before:
This system replaced the city or county background check associated with the Tennessee Application for Permission to Purchase a Handgun. The dealer gave you a form in triplicate to fill out, you took it to the city police or county sheriff office. The police chief or sheriff had up to fifteen days to conduct a background check and approve or deny the application. Failure to respond in fifteen days was a default approval. I bought a Ruger Mark II pistol at a county gunshop, drove to the county sheriff office and turned in the triplicate forms, drove home; the next day, the gunshop called, the approved dealer and buyer copies had arrived in the morning mail, and I went to get my gun and buyers form at the shop. I bought a Grendel P10 pistol at a city gunshop, walked the forms to the police station, the clerk told me to wait, returned witth the dealers and buyers forms stamped no records found. It was a nice day, I got some exercise.