WASHINGTON--A federal appeals court has approved the dismissal of a case challenging the legality of the Deficit Reduction Act of 2005, which mandates a 36-month cap on oxygen rental and a 13-month rental cap on DME.

In March 2006, watchdog group Public Citizen filed a lawsuit in federal district court to challenge the DRA on grounds that it was not a valid law because both houses of Congress had not passed the exact version of the bill signed by President Bush.

As the original legislation was sent back and forth between the House and Senate, a typo involving the number of months of the DME rental cap was inserted into the House version. The Senate passed a version of the bill without the typo, which was then signed by the president. Under the Constitution, bills passed by both congressional chambers should be identical.

Last August, the U.S. District Court for the District of Columbia dismissed the lawsuit, citing the "enrolled bill rule" in the 1892 court case Marshall Field v. Clark. Under the rule, the signatures of the Speaker of the House, the President of the Senate and the President of the Unites States make an enrolled bill "complete and unimpeachable." Public Citizen then appealed that decision.

But the U.S. Court of Appeals for the D.C. Circuit affirmed the dismissal in a decision issued May 29.

"We are disappointed with today's appellate court decision affirming the dismissal of Public Citizen's challenge to the Deficit Reduction of 2005," Allison Zieve, the group's attorney, said in a statement. "We are also disappointed that, in this case, the courts have not been willing to stand up for a basic principle of our Constitution: the requirement that both chambers of Congress pass identical versions of a bill before that bill can be signed into law by the president."

Zieve said Public Citizen has not yet decided whether it will pursue the case further.