Elizabeth Holmes founded her revolutionary blood diagnostics company, Theranos, when she was 19. It’s now worth more than $9 billion, and poised to change health care.

In the fall of 2003, Elizabeth Holmes, a 19-year-old sophomore at Stanford, plopped herself down in the office of her chemical engineering professor, Channing Robertson, and said, “Let’s start a company.”

Robertson, who had seen thousands of undergraduates over his 33-year teaching career, had known Holmes just more than a year. “I knew she was different,” Robertson told me in an interview. “The novelty of how she would view a complex technical problem–it was unique in my experience.”

Holmes had then just spent the summer working in a lab at the Genome Institute in Singapore, a post she had been able to fill thanks to having learned Mandarin in her spare hours as a Houston teenager. Upon returning to Palo Alto, she showed Robertson a patent application she had just written. As a freshman, Holmes had taken Robertson’s seminar on advanced drug-delivery devices–things like patches, pills, and even a contact-lens-like film that secreted glaucoma medication–but now she had invented one the likes of which Robertson had never conceived. It was a wearable patch that, in addition to administering a drug, would monitor variables in the patient’s blood to see if the therapy was having the desired effect, and adjust the dosage accordingly.

“I remember her saying, ‘And we could put a cellphone chip on it, and it could telemeter out to the doctor or the patient what was going on,’ ” Robertson recounts. “And I kind of kicked myself. I’d consulted in this area for 30 years, but I’d never said, here we make all these gizmos that measure, and all these systems that deliver, but I never brought the two together.”

Still, he balked at seeing her start a company before finishing her degree. “I said, ‘Why do you want to do this?’ And she said, ‘Because systems like this could completely revolutionize how effective health care is delivered. And this is what I want to do. I don’t want to make an incremental change in some technology in my life. I want to create a whole new technology, and one that is aimed at helping humanity at all levels regardless of geography or ethnicity or age or gender.’ ”