South Carolina owes the federal government $445,000 for a Medicaid error, a new report shows.

The mistake was identified in an audit spanning 18 months during 2011 and 2012.

According to the report, the state Medicaid agency sometimes used an incorrect percentage to calculate the level of federal matching funds. The agency generally used an accurate percentage, the report acknowledged.

The state Medicaid agency spends more than $6 billion a year, rendering the accounting error relatively minor. A spokeswoman for the agency said it has taken steps to avoid the same issue in the future.

Medicaid is jointly funded by the federal and state governments to provide health insurance for low-income adults and children. States have some latitude to shape their own Medicaid programs, but are largely bound by federal rules.

"Like each of the hospitals and physicians we work with in South Carolina, we appreciate each and every audit the federal government performs on us to make sure we are in compliance with federal rules," said S.C. Medicaid Director Tony Keck.

Other states have been cited for similar errors in the past. In April, the federal government reported that Georgia owed nearly $11 million for Medicaid errors between 2008 and 2011.

Reach Lauren Sausser at 937-5598.