ST. PAUL — The Office of the Legislative Auditor said Wednesday that it found no evidence that the state of Minnesota overpaid two companies it hired to conduct mail in and other rapid COVID-19 saliva testing.

Instead, the auditor’s report said, managed care organizations. acting on behalf of the state, scrutinized the claims submitted by the two companies and paid just a fraction of the amounts originally billed.

The Minnesota Department of Health signed an emergency contract last November with Vault Medical Services and Infinity BiologiX. The auditor conducted the review in response to complaints of excessive billing. The companies have collected and processed millions of COVID-19 tests taken by Minnesotans.

Vault and IBX officials told the auditor’s office that the big differences between the bills they submitted and the discounted amounts approved by health plans weren’t unusual, and were consistent with reimbursement processes across the industry.

The review did not examine payment practices for individuals whose testing was covered by private insurance. The report said it’s possible that some private insurers have paid more than the health plans operating under contract to the state, if those insurers did not challenge the claimed amounts.

The state is liable under the terms of its contract for up to $75 million that are not covered by other payors such as health plans, but has paid only $3.1 million so far.