Tennessee's highest-ranked hospital will be out of network for all Obamacare customers next year, after Blue Cross's abrupt withdrawal from the state's insurance marketplace last month.

Vanderbilt University Medical Center confirmed to the Washington Examiner that it will be outside the networks of medical providers covered by the three insurers selling marketplace plans for 2017.

The hospital system, which is ranked nationally in nine adult and 10 pediatric specialties, is in network this year for Tennessee residents with Blue Cross marketplace plans. But Blue Cross announced in September it is withdrawing from the major urban areas of Memphis, Knoxville and Nashville, where Vanderbilt is located.

Vanderbilt spokesman John Howser said the hospital is participating in individual plans only outside the marketplaces next year.

"As of now, we are participating in off-exchange options offered through Aetna and Farm Bureau," Howser said. "If viable opportunities present for expanding our participation in the exchange we will consider them."

Vanderbilt's exclusion from the marketplace plans, which covered 231,700 Tennessee residents this year, is a particularly troubling development for patients who relied on the hospital's top-ranked services in cancer, cardiology and other areas.

Known for its innovations with electronic medical records, Vanderbilt's medical system includes a highly acclaimed teaching hospital and a children's hospital. Its providers see more than 1.6 million patients and perform more than 35,000 surgical procedures annually.

Walter Davis, executive director of the consumer advocacy group Tennessee Health Care Campaign, said the decision also will affect consumers in rural areas particularly near Nashville, who relied on Vanderbilt for specialty care.

"I've had friends in rural communities who have had transplants there," Davis said. "It will be worrisome until we see what it means in terms of delivery and access to care."

Blue Cross's exit is part of a nationwide trend of insurers pulling back from the Affordable Care Act marketplaces after experiencing heavy financial losses. Independent analysts have said one-third of the country may have just one Obamacare insurer next year.

Blue Cross Blue Shield of Tennessee is dropping coverage for 130,000 customers next year. It will continue selling plans in rural areas of the state, where it covers about 80,000 people.

Cigna and Humana also will sell marketplace plans next year, but only in some parts of the state, leaving 73 of Tennessee's 95 counties with just one Obamacare insurer.

The Tennessee Health Care Campaign blasted Tennessee's insurance commissioner on Thursday for approving Blue Cross's 62 percent increase in premium rates and narrow networks and called the insurer's exit from urban areas "shameful."

Davis said he worries the plan cancellations will hurt enrollment by creating churn in the market and confusing consumers.

"It creates a sense of insecurity and fear for a lot of people," Davis said. "I can tell you there's a lot of anger."