Anadolu Agency said a high court in Izmir upheld a lower court's decision earlier this week to keep pastor Andrew Brunson under house arrest. It also rejected an appeal for his travel ban to be lifted, Anadolu reported.
Brunson's continued detention has aggravated a feud between the NATO allies and has helped trigger a Turkish currency crisis.
U.S. President Donald Trump's administration on Thursday signaled new sanctions against Turkey over Brunson's detention and Turkey said it would reciprocate.
Turkey's currency remains steady against the dollar despite an apparent threat of possible new sanctions by U.S. President Donald Trump.
The Turkish lira stood at 5.80 per dollar on Friday, up about 0.4 percent against the dollar.
The currency has recovered from record lows earlier this week. Investors, already worried about Turkey's economy, were irked by a diplomatic and trade dispute with the United States over Brunson's continued detention on espionage and terror-related charges.
In a tweet on Thursday, Trump urged Brunson to serve as a "great patriot hostage" while he is jailed and criticized Turkey for "holding our wonderful Christian Pastor."
Trump added: "We will pay nothing for the release of an innocent man, but we are cutting back on Turkey!"