CASPER, Wyo. --- Wyoming Medical Center altered hospital records to collect higher fees from the Medicare and Medicaid programs by having its records clerks change the admission status of patients, a whistleblower charges in a federal lawsuit unsealed this week.

The lawsuit, filed by a hospital worker in 2007, said the changes allowed the hospital to seek at least nearly $10,000 in higher reimbursements from the federal insurance programs.

The whistleblower, a worker named Gale Bryden who has since left the hospital, suspected the practice continued even after she notified top hospital administrators in the fall of 2006. Bryden contends she shared her concerns with Vickie Diamond, who was chief operating officer at the time and is now the hospital's president.

Hospital attorney Dick Williams denied any attempt by the hospital to defraud the government or private insurers. If mistakes did occur, they were inadvertent or accidental, he said.

Diamond said she has no memory of meeting with Bryden to discuss concerns about fraudulent billing.

"There is no recollection from my part or from anybody else," she said.

Bryden, who was responsible for collecting fees that had been denied by insurers, filed the lawsuit on behalf of the federal government in October 2007. The lawsuit seeks a percentage of any award or settlement in the case.

Because she made the allegations under a federal whistleblower law, the suit was put under seal as the government investigated the matter. U.S. District Judge Scott Skavdahl ordered the documents unsealed Monday.

Federal attorneys notified the court last week that the government wouldn't be intervening in the case for now because its investigation isn't complete.

Other court documents related to the case, including two amended complaints filed by Bryden's attorney in 2008 and 2009, remain under seal. In the unsealed documents, there is no mention about whether the alleged wrongdoing continued after Bryden filed her original complaint.

Bryden no longer works for the hospital. Diamond said she doesn't know the circumstances that led to Bryden's departure.

Bryden observed workers submitting claims to insurers that differed from the services the hospital actually provided. The workers altered patients' admission status from "outpatient" to "inpatient" without a doctor's order, the lawsuit says.

"WMC, by and under the direction of the highest levels of hospital management, was submitting claim forms that were inconsistent with the medical records for the purpose of obtaining higher levels of reimbursements from both the private and government program insurers," the lawsuit states.

The lawsuit cites 21 examples of clerks modifying patient records, resulting in increased charges ranging from $35 to $1,100.

Wyoming Medical Center has cooperated with the government's investigation since officials were notified of it in May 2009, said Williams, the hospital attorney. The hospital has provided the Department of Justice with information on claims from 2002 through 2009.

"We have denied from day one that there was any intent to improperly bill the government ... or that there was a systematic direction from anyone to alter statuses or records," he said.

Medicare and Medicaid regulations can be difficult to understand and the hospital does its best to comply with the rules, Williams said.