Federal auditors estimate Lafayette General Medical Center overbilled Medicare for more than $4.4 million over two years, a finding hospital administrators say they mostly dispute and plan to appeal.

The U.S. Department of Health and Human Services’ Office of Inspector General released the audit on Monday. It’s one in a nationwide series of hospital compliance reviews.

Auditors reviewed a sample of 134 claims submitted to the Centers for Medicare and Medicaid Services and found 69 of those claims were improperly billed.

“These errors occurred primarily because the hospital did not have adequate controls to prevent the incorrect billing of Medicare claims within the selected risk areas that contained errors,” according to the report.

LGMC took responsibility for 18 of the improperly billed claims, according to the audit.

A spokesman on Wednesday issued a statement saying hospital officials plan to appeal the remaining findings.

“We disagree with over 85 percent of the OIG’s conclusions. We continue to maintain that our claims were properly billed and will appeal each claim, one by one, until resolution is achieved,” the statement reads.

The statement iterates that the improper billing, which mainly centers around whether a patient was classified under inpatient or outpatient status when submitting a Medicare claim, was because of “clerical errors in attempting to navigate a complex coding system.”

Auditors recommend the hospital refunds Medicare the full $4.1 million, ensure the amount the hospital already repaid was recovered by Medicare and strengthen its operations to ensure Medicare compliance.

Auditors reviewed LGMC Medicare claims from Jan. 1, 2013, to Dec. 31, 2014, and used data analysis to pull about 2,100 claims deemed most at risk for noncompliance, then pulled the 134-claim sample for direct review, according to the audit.

The audit states the 69 improperly billed claims resulted in about $865,000 in overpayments.

From that figure, auditors estimated the hospital overbilled about $4.4 million total.

The figure represents about 4 percent of the hospital’s total Medicare claims during the audited period, which totaled about $118 million.

LGMC has already refunded about $287,000.

The hospital estimates the appeals process will last from two to four years.

Follow Lanie Lee Cook on Twitter, @lanieleecook .