Sen. Susan Collins, a key centrist Republican, said Thursday that a score would be needed from the Congressional Budget Office to determine the effect that a repeal and replace bill for Obamacare would have on constituents.

"Although I will carefully review the legislation the House passed today, at this point, there seem to be more questions than answers about its consequences," she said in a statement about a bill the House advanced to repeal Obamacare.

She detailed what she would be looking for in the legislation, including what the effect would be on the uninsured, how much people would pay in premiums, how the bill treats people with pre-existing illnesses and whether special education would be affected.

Collins released her statement shortly after the House voted to pass the bill, which was not scored by the Congressional Budget Office. The nonpartisan agency makes projections about how many people would no longer have insurance and what the costs would be to the federal government.

"This is an extremely important debate with significant implications for millions of Americans," Collins said. "We need to spend the time necessary to get this right and work to achieve the goal of expanding access to health care that is truly affordable and accessible."

The Senate is planning to draft its own bill rather than take up the House version of the bill. Collins has co-authored her own Obamacare repeal and replace bill with Sen. Bill Cassidy, R-La., which would allow states to decide whether they want to keep Obamacare in place or craft an alternative model.

"Our current health care system is under considerable stress," Collins added. "In several states, the individual insurance market is on the verge of collapse, leaving consumers with no insurer willing to sell them insurance that qualifies for ACA subsidies. In many other states, those who do have coverage are experiencing large increases in premium costs, deductibles, and co-pays."

Collins is a key centrist vote in a Senate where Republicans hold just 52 seats.