STORY: Elizabeth Holmes reported to prison Tuesday to begin serving her 11-year sentence for fraud.

The 39 year-old shot to fame as the chief executive of the now-defunct blood-testing startup Theranos, a company once valued at $9 billion.

Holmes had boasted Theranos would revolutionize medical diagnoses with just a simple pinprick, with machines she said could run a battery of tests with just a few drops of blood.

But the firm collapsed after a series of articles in the Wall Street Journal in 2015 questioned the technology.

Holmes - once the world's youngest female self-made billionaire - was subsequently convicted of fraud at trial in California last year. Prosecutors said that Holmes misrepresented Theranos' technology and finances.

She testified in her own defense and said she believed her statements were accurate at the time.

Holmes is appealing her conviction and a number of the judge's rulings from her trial.

Her co-defendant was former Theranos President Ramesh 'Sunny' Balwani.

He was convicted of defrauding investors and patients at a separate trial, and sentenced to just under 13 years in prison.

He began serving his sentence in April.