Crowdsourcing diagnosis platform CrowdMed raised $2.4 million from actor Patrick Dempsey, NEA, Andreessen Horowitz, Greylock Partners, SV Angel, Khosla Ventures and Y Combinator. Grey's Anatomy actor Dempsey will also help to expand the company's platform by  developing new partnerships with insurance companies so that patients are incentivized to use the platform.

This recent funding is a continuation of the round CrowdMed started in April 2013. At the time, CrowdMed had raised $1.1 million.

"After meeting with several Silicon Valley healthcare startups, I was immediately drawn to CrowdMed's mission of helping those who have run out of alternatives," Dempsey said in a statement. "I remember being overwhelmed when my mother was diagnosed with ovarian cancer almost a decade ago, and I know how challenging it can be trying to make the best medical decisions for oneself or a loved one. The patients who are turning to CrowdMed can't even begin to think about treatment options because they haven’t been able to find an accurate medical diagnosis yet – but hopefully we can change that."

CrowdMed applies the theory of a prediction market -- that when a large enough population bets real or fake money on predictions in a system similar to a stock exchange, their bets will reflect their confidence and, in aggregate, will create a robust predictive model -- to healthcare.

Patients or caregivers can post medical cases on the platform anonymously. Other patients and medical experts can then see these cases and collaborate with each other to find solutions to a case and then vote on the diagnosis they think is correct. CrowdMed then applies the prediction market technology to solve the problem addressed in the case. When a case is "solved",  CrowdMed encourages the patient to discuss CrowdMed's potential diagnosis with their physician.

People who work on these cases are labeled "medical detectives". The company currently incentivizes these detectives to work on cases with a cash reward system. CrowdMed also compiles a list of next steps that is given to patients who receive a crowdsources diagnosis. Next steps might include treatment ideas, diagnostic tests, and dietary or lifestyle changes.