John Doerr David Paul Morris | Bloomberg | Getty Images

John Doerr made a fortune for his venture firm through an early investment in Amazon, when it was just an online bookseller. More than two decades later, he's betting the company is preparing for a big move into health care. Speaking at the Forbes Healthcare conference this week, Doerr said Amazon is among the best-positioned companies to take information its learned from customers and use it to their benefit. He's expecting CEO Jeff Bezos to roll out an offering for medical and health products that resembles Amazon Prime, which has over 100 million users.

"Imagine what it's going to be like when he rolls out Prime Health, which I'm convinced he will," said Doerr, chairman of Kleiner Perkins, the firm he joined in 1980. Doerr, who also backed companies including Google and Intuit, led Kleiner's investment in Amazon in 1995 and sat on the e-retailer's board until 2010. Doerr didn't say whether he'd spoken with Bezos about his plans in health care, but the two remain close. As CNBC reported in March, Doerr was involved in helping to find someone to lead the joint health initiative between Amazon, Berkshire Hathaway and J.P. Morgan Chase.

Amazon isn't the only company that Doerr expects to play a role in pushing health care forward. Despite Google's failed efforts with an earlier electronic medical records product called Google Health, Doerr still sees Alphabet as player in the market, and he should know since he's on the board. Doerr praised Verily, Alphabet's life sciences unit, as a more promising project, as well as the various artificial intelligence research groups like Google Brain. He also wouldn't rule out Microsoft as an enterprise-focused health player, given the software giant's efforts to get doctors using cloud technology. Doerr is ultimately hoping that entrepreneurs and tech companies will start to build on top of traditional electronic medical records companies, like Epic and Cerner, rather than replace them altogether. "This is a theme of mine," he said.

From ad-tech to health-tech