Two of California's largest health insurers are partnering to create a massive database of patient medical records.

With just a few strokes of a keyboard, doctors and nurses will be able to access the medical histories of about one in four California residents.

Supporters say the effort by Anthem Blue Cross and Blue Shield of California could mean faster, cheaper and better healthcare. But the system faces significant technological challenges and privacy concerns.

The benefits could prove useful in emergency rooms, where doctors would be able to review patients' histories instantly. It's expected to go online by the end of the year.

“We need to bring healthcare into the digital age, and by doing so you can really improve the quality and cost of care,” said Paul Markovich, chief executive of Blue Shield of California.

Insurers say the new system, called Cal Index, will help save money be reducing repetitive tests and procedures. Anthem and Blue Shield are providing $80 million in seed money to start the nonprofit database, with the hope it ultimately will survive on subscriptions paid by health providers.

Technological challenges have caused previous attempts to fail.

“It’s very difficult,” said Donald Crane, chief executive of the California Assn. of Physician Groups. “Everybody’s got a different kind of data, with different definitions, different fields.”

Patient privacy is another concern, said Pam Dixon, executive director of the World Privacy Forum.

People who suffer from rare diseases, domestic-abuse victims and others are often concerned about keeping their records private, Dixon said.

“Health information exchanges have the potential for good," she said. “There are a whole lot of people with a lot of concerns, and most don’t know how to exercise their rights. It’s not easy.”

©2014 the Los Angeles Times