Senate Finance Committee negotiators are under pressure from the senior lobby AARP and the clinical lab industry to reject the use of Medicare clinical lab co-payments to help pay for a health overhaul.

An AARP official reacted strongly Thursday to reports that the committee would consider charging co-payments. Saying that President Obama has twice assured AARP members that he won’t cut Medicare benefits to pay for an overhaul, AARP legislative policy director David Cerner warned in an interview that “to turn around and cut Medicare benefits is going to significantly affect support for health care reform.”

Assuring senior support for a health overhaul is already a delicate issue for Democrats because of several hundred billion dollars in planned Medicare cuts to hospitals, health plans, and other providers. Arguably those cuts would not affect care to seniors because of improvements in provider efficiency. But AARP is drawing the line at Medicare revisions that would cut benefits or add to out-of-pocket costs.

Democrats also have asserted that a health overhaul will lower cost burdens. But AARP lobbyist John Rother noted that “any requirement that seniors be billed for part of the cost of laboratory services would simply shift costs to beneficiaries, not save costs. Lab services are a function of physician decisions, not patient preferences,” Rother added in an e-mail message.

“Adding the paperwork and additional overhead associated with collections for coinsurance would add costs to the system, not save costs. It would make Medicare less efficient and raise the costs of supplemental insurance coverage. For these reasons, AARP opposes this idea,” Rother said.

In a letter last week to House Energy and Commerce Committee Chairman Henry A. Waxman, D-Calif., AARP CEO Barry Rand wrote, “AARP cannot support any efforts to target Medicare beneficiaries for increased cost-sharing or other benefit cuts,” he said. “In addition, we cannot support backdoor attempts to finance health care reform through increases in beneficiary costs or reductions in benefits, for example, through use of commissions or other process mechanisms.”

A July 31 letter from 26 clinical lab industry groups to the Finance Committee said that “the 20 percent Medicare laboratory co-pay being proposed by the Senate Finance Committee financially burdens both beneficiaries and laboratories and will not accomplish any change in utilization, because laboratory services are ordered by health care professionals, not initiated by patients. The result of this proposed policy is not a cost savings to our health care system, but rather, a staggering new $23 billion cost shift to seniors.”

“It is important to understand that for the majority of the top 100 laboratory procedures, beneficiaries would pay less than $2 in co-payment,” the letter added. “In addition to the burden and confusion these 134 million bills will create for seniors, the cost of collecting $23 billion in these small amounts will exceed the co-pay itself . . . Laboratories do not have a direct relationship with seniors and under Medicare, and by law, labs must make repeated attempts to collect the co-pays.”

An aide to Senate Finance Committee Chairman Max Baucus, D-Mont., declined to address the co-payment issue directly, but said the committee “is absolutely dedicated to protecting seniors and ensuring that care is accessible, affordable and sustainable for all seniors and all Americans.”