The price tag of a House bill to reform the Department of Veterans Affairs is causing concern among conservatives as the House and Senate move to blend their respective measures into a final product to send to President Obama to sign.

"Nobody thought that number would come in that high," one House Republican source told Fox News, referring to the $44 billion price tag the Congressional Budget Office assigned to portions of several House VA bills. The total cost was put as high as potentially $54 billion.

The bipartsan Senate bill approved last week would cost $35 billion.

When asked if the cost was enough to blow up the bill, another source replied emphatically "yes."

The ultimate cost is contingent on how many veterans use the benefits and what care they seek.

The House of Representatives appointed its members for a  conference committee Wednesday. Fox News was told the Senate would do the same later in the day, and the conference committee meeting appeared likely to begin next week.

Fox News' Chad Pergram contributed to this report