Facing attacks from organ transplant centers and Congress, the federal government yesterday clarified its regulations aimed at getting organs to the sickest patients. Organs should not be wasted by shipping them coast to coast or futilely transplanting them into very sick patients, according to the new rules.

But the revised regulations issued by the Department of Health and Human Services remain unchanged in fundamental ways: Organs should be given to the most medically urgent patients first, without regard to where they live. The HHS secretary also retains the right to approve or veto any allocation plan devised by the private contractor, the United Network for Organ Sharing (UNOS), that runs the transplant system.

HHS issued regulations directing a remake of the transplant system last year, arguing that patients in certain communities unfairly wait much longer than others. Under the current system, organs are distributed in local areas first, even if sicker patients are elsewhere.

Congress put these rules on hold amid fierce complaints from transplant programs that feared they would lose locally donated organs to larger centers that have more patients on waiting lists. Surgeons and UNOS also objected to HHS setting the rules, saying allocation policies are medical decisions that medical experts should make.

HHS Secretary Donna E. Shalala told reporters yesterday that many of the revisions are meant to clarify what the department wanted all along. "Members of the transplant community read it one way when we actually thought we were pretty clear," she said.

The revised rule--to take effect in about 30 days--says allocation should be based on "sound medical judgment" and calls for organs to be distributed "over as broad a geographic area as feasible."

Last year, Congress ordered the Institute of Medicine to study the system and make recommendations. That report, released in July, recommended that the government should exercise more oversight and concluded that broad sharing of organs was appropriate.

HHS repeatedly cited that study in releasing its revisions yesterday.

Also in line with the institute's report, the new regulations no longer require the allocation system to consider the amount of time a patient has been waiting for a transplant. And they establish an expert advisory committee to help guide HHS policy.

The revisions also:

* Retain new requirements to produce timely data about transplant center performance.

* Give the transplant network power to enforce rules about who is put on the waiting list. This is to ensure that certain hospitals are not unfairly listing their patients as sicker than they are to get organs quicker.

* Allow for monitoring the impact of the new rules on small and medium-sized programs.