Holmes told CNBC's Squawk Box that her fear of blood, combined with the experience of losing family members too early to disease, motivated her push for an accessible blood test.
"The true legacy of Silicon Valley is to build great products that can make a difference in the world," she said.
Theranos' finger-prick test uses only a small amount of blood to test for a certain disease, unlike traditional blood tests that usually require multiple vials of blood.
In July, the company got FDA approval for its first test, and later got the FDA's OK to start administering the test outside of the traditional lab setting. Theranos has partnered with pharmacies, specifically Walgreens, around the US to allow patients to go in and get the quick blood test.
And after last week's biotech drug price news, Holmes reassured CNBC that "We are advocating that transparency on pricing is essential, and one of the most exciting things about what we've done is that physicians will look at our prices and call up other labs and say 'if you don't match these prices we're not sending you our patients.'"