The world's youngest female billionaire said Tuesday her company, Theranos, which aims to democratize blood tests to enable early detection of diseases, is not for sale.
"We're not going to be bought," Elizabeth Holmes told CNBC's "Squawk Box." If approached, she said, she would say "we have an incredibly long-term vision and we're flattered by the call, but we're just getting started."
And what a start it's been.
At just 19, Holmes founded Palo Alto, California-based Theranos in 2003, and dropped out of Stanford University a year later. She's raised more than $400 million in funding, and she owns 50 percent of the diagnostics company, which is valued at $9 billion.
She said her "traumatic fear of blood" helped motivate her to build Theranos. "It [also] came from losing my family members and people that I loved, and the belief ... the true legacy of Silicon Valley is to build great products that can make a difference in the world."
Now 31, Holmes said she has no plans to go public, and that Theranos can continue to grow as a privately held company.
The goal of Theranos is making lab testing more widely available so people can find out whether they're sick in time to do something about it, she said. "We were looking for a way to build a system that could help make early detection and prevention [of diseases] a reality in our health-care system."
Holmes, who holds more than 80 patents, said she's developed tests that use smaller blood samples and cost much less than those of competitors such as Laboratory Corporation of America and Quest Diagnostics.
Through just over 50 Walgreens and standalone Theranos locations, the 12-year-old company has designed 150 tests that cost less than $10. "Our tests are anywhere from 50 percent to 80 percent off of Medicare rates, which means something like a cholesterol test is $2.99," she said.
"The reason the market doesn't function in health care [is] because individuals have absolutely no visibility into pricing," she said. "But you have a right to the lowest cost, highest quality product. And right now, there's not even a demand for that because there's no pressure to build a greater product at a lower price."
She's looking to change that. "[We] tried to focus on consumerizing the whole lab experience in the context of incredibly low prices, transparent prices, a wonderful experience though which to get tested, and smaller blood samples so that it's not as traumatizing to people like me who otherwise won't get tested."
Addressing critics of the secrecy surrounding Theranos, Holmes said her company is the first and only lab to commit to proactively submitting all developed tests to the Food and Drug Administration for clearance and approval.
As part of its 25th anniversary celebration last year, CNBC choose 25 business leaders who disrupted industries, sparked change and exercised an influence far beyond their own companies. The CNBC First 25 list was then followed by the Next List, which picked Holmes as one of the entrepreneurs, financiers, inventors and executives working on innovative solutions to global challenges.