A court has ruled that disgraced Theranos founder Elizabeth Holmes must report to prison on 30 May, while she appeals against her fraud conviction.
Holmes, 39, had asked a judge to remain free while she fought against her jail sentence for a blood-testing hoax.
She was sentenced to over 11 years in prison after a jury last year found her guilty of defrauding investors.
In a separate ruling, US District Judge Edward Davila also ordered Holmes to pay $452m (£364m) to victims.
She will split the multi-million dollar payment with her former romantic and business partner, ex-Theranos boss Ramesh "Sunny" Balwani.
The BBC has reached out to Holmes' attorneys for comment.
Balwani was sentenced to 13 years in prison after being convicted on 12 counts of fraud and conspiracy last year. He began serving his sentence in April after losing his own attempt to remain free while appealing against his conviction.
The court has recommended Holmes serve her time behind bars at a federal minimum-security women's prison in Bryan, Texas.
Holmes had asked the Ninth Circuit Court of Appeals to delay her sentence days before she was supposed to report to prison last month.
The Theranos founder had said that she would raise "substantial questions" about her case that could warrant a new trial, an argument that Judge Davila had rejected.
"Contrary to her suggestion that accuracy and reliability were central issues to her convictions, Ms Holmes' misrepresentations to Theranos investors involved more than just whether Theranos technology worked as promised," he said at the time.
Holmes' attorneys also argued she should remain free while appealing against her case to care for her children.
The mother of two has been living in San Diego, California, with her partner, hotel heir William Evans, as well as their one-year-old son William and three-month-old daughter Invicta.
Once hailed as the "next Steve Jobs", Holmes was said to be the world's youngest self-made billionaire.
She started Theranos after dropping out of Stanford University. During her time leading the company, Holmes was able to raise millions of dollars from high-profile investors, including media mogul Rupert Murdoch, former Secretary of State Henry Kissinger and Oracle founder Larry Ellison.
But the start-up crashed in 2018 after investigations revealed its technology did not work. The blood-testing device was purported to be able to run a multitude of tests from just a few drops of blood.
The company's downfall was documented in a TV series, an HBO documentary and a podcast.
She was sentenced to over 11 years in prison after a jury last year found her guilty of defrauding investors.
In a separate ruling, US District Judge Edward Davila also ordered Holmes to pay $452m (£364m) to victims.
She will split the multi-million dollar payment with her former romantic and business partner, ex-Theranos boss Ramesh "Sunny" Balwani.
The BBC has reached out to Holmes' attorneys for comment.
Balwani was sentenced to 13 years in prison after being convicted on 12 counts of fraud and conspiracy last year. He began serving his sentence in April after losing his own attempt to remain free while appealing against his conviction.
The court has recommended Holmes serve her time behind bars at a federal minimum-security women's prison in Bryan, Texas.
Holmes had asked the Ninth Circuit Court of Appeals to delay her sentence days before she was supposed to report to prison last month.
The Theranos founder had said that she would raise "substantial questions" about her case that could warrant a new trial, an argument that Judge Davila had rejected.
"Contrary to her suggestion that accuracy and reliability were central issues to her convictions, Ms Holmes' misrepresentations to Theranos investors involved more than just whether Theranos technology worked as promised," he said at the time.
Holmes' attorneys also argued she should remain free while appealing against her case to care for her children.
The mother of two has been living in San Diego, California, with her partner, hotel heir William Evans, as well as their one-year-old son William and three-month-old daughter Invicta.
Once hailed as the "next Steve Jobs", Holmes was said to be the world's youngest self-made billionaire.
She started Theranos after dropping out of Stanford University. During her time leading the company, Holmes was able to raise millions of dollars from high-profile investors, including media mogul Rupert Murdoch, former Secretary of State Henry Kissinger and Oracle founder Larry Ellison.
But the start-up crashed in 2018 after investigations revealed its technology did not work. The blood-testing device was purported to be able to run a multitude of tests from just a few drops of blood.
The company's downfall was documented in a TV series, an HBO documentary and a podcast.