“When people say, ‘I want to start a business,’ ” Theranos founder and CEO Elizabeth Holmes said Wednesday, “my question is always, ‘Why?’ Because there’s got to be a mission—there’s got to be a reason you’re doing it so that no matter how hard it is, you want to keep doing it over and over and over again, because you love it.”

“And if you know what it is you’re trying to do,” she continued, “then it’s a question of being very, very open to failure.” Her attitude, she said, was: “We will fail over a thousand times till we get this thing to work, but we will get it on the 1001st time.”

Holmes made these remarks during the closing interview of Fortune‘s 2014 MPW Next Gen conference at San Francisco’s Ritz-Carlton Hotel. She was interviewed by Fortune senior editor at large Pattie Sellers, who is also Executive Director, MPW/Live Content, Time Inc.

Holmes, a prodigious inventor who is still just 30, was the subject of a Fortune cover story in June. She dropped out of Stanford at age 19 to found Theranos, whose name is an amalgam of the words “diagnosis” and “therapy.”

Her own mission, as she explained, is to enable very early detection of disease, before symptoms become manifest, when there is the best chance of a cure. Her goal is to “make a change in our world, so that people won’t have to say goodbye too soon” to the ones they love after a diagnosis that came too late to do anything about it.

Theranos is now able to perform hundreds of blood tests from just a few drops of blood—drawn painlessly from a fingerstick rather than with a needle-and-syringe—at a cost that is generally one-quarter to one-tenth of what incumbent players currently charge. Investors value the private company at more $9 billion, and Holmes retains more than half the stock.

At the start of the interview, Sellers congratulated Holmes for having just been named one of 12 recipients of the 2015 Horatio Alger Award for “exceptional leaders.” She is the youngest recipient since the award’s initiation in 1947. (It is given by the Horatio Alger Association, which grants scholarships and encourages youth to pursue their dreams through higher education.)

Holmes told Sellers she looked forward to the “opportunity to connect with so many young people … with little girls in particular, who don’t often get to hear from young women who have really pursued science and engineering and business.” She said she wanted to tell those girls, “Yes, it’s something that’s cool, and something that they can excel in.”

Holmes’ company has been expanding rapidly, having grown from 500 to 700 employees even since Fortune wrote about it just five months ago. Its phlebotomists now draw blood from patients by fingerstick at dedicated “wellness centers” at more than 40 Walgreens in Arizona and one in Palo Alto, Calif., often emailing back results to both the patient and physician within hours.

Walgreens, which has 8,200 drugstores in the U.S., has committed to gradually rolling out the centers nationwide. Within five years, Holmes said, she hopes to have one of her centers within five miles of nearly everyone in the United States.

Theranos also performs tests on conventionally drawn samples sent to the company from clinical practices and hospital systems, which often simply want the cost savings of Theranos’ tests.

In response to questions from conference participants, Holmes said that she slept four hours a night, and that her number one priority at the moment was finding the “right people” and to train them to help build the business.

Asked if she was experiencing “regulatory pushback,” she said that, to the contrary, she was embracing regulation. She recognizes, she says, that for physicians and patients to rely on her tests, they must have the highest level of confidence in their accuracy. For that reason she is “proactively submitting every test we perform to the FDA” for approval, even though the law does not require that these tests be approved by the agency. “We embrace regulation because we see it as critical to realizing our mission.”

One participant asked how she knew the time was right to drop out of such an excellent institution as Stanford to pursue her business? “That moment is when you find what you were born to do,” she responded. “For me, I reached the point where I was spending all my time doing this anyway, and I was wasting my parents’ money on courses I wasn’t going to. So I had that moment where I was very clear: This is what I wanted to do with my life.”