Theranos founder Elizabeth Holmes has been ordered to report to prison on May 30 to begin her sentence for defrauding investors in the failed blood-testing start-up once valued at $9 billion.
US District Judge Edward Davila set the date on Wednesday. Holmes, 39, has been sentenced to 11 years and three months in jail.
Holmes rose to fame after claiming Theranos's small machines could run an array of diagnostic tests with only a few drops of blood. She was convicted of fraud last year at a trial in San Jose, California.
She asked the Ninth Circuit Court of Appeals to delay her sentence on April 25, two days before she was originally to report to prison. The court denied the request on Tuesday.
Mr Davila, who oversaw Holmes's trial and sentencing, previously rejected her argument that the appeal was likely to result in a new trial, the threshold for her to remain free on bail.
Prosecutors said during the trial that Holmes misrepresented Theranos's technology and finances. Holmes gave evidence in her own defence, saying she believed her statements were accurate at the time.
In her appeal, Holmes has challenged several of the judge's rulings, including his allowance of evidence about Theranos's test accuracy that came after her statements to investors.
Holmes's co-defendant, former Theranos president Ramesh Balwani, was convicted of defrauding Theranos's investors and patients at a separate trial.
He was sentenced to 12 years and 11 months in prison.
Balwani began his sentence on April 20, after Mr Davila and the Ninth Circuit court rejected his request to remain free on bail during his appeal.
Forbes described Holmes as the world's youngest female self-made billionaire in 2014, when she was 30 and her stake in Theranos was worth $4.5 billion.
Theranos collapsed after a series of reports in The Wall Street Journal in 2015 that questioned its technology.