Medicare Audit Improvement Act of 2013

Medicare Audit Improvement Act of 2013 - Directs the Secretary of Health and Human Services (HHS) to establish a process which subjects to a single, combined maximum annual limit, applied incrementally, the number of additional documentation requests made to a hospital by Medicare administrative contractors, recovery audit contractors, or Comprehensive Error Rate Testing (CERT) program contractors pursuant to prepayment and postpayment audits requiring a hospital to submit a medical record for audit purposes.

Directs the Secretary also to establish a distinct additional documentation request limit, computed according to a specified formula, for each hospital claim type for each hospital for a 45-day period in a year.

Amends title XVIII (Medicare) of the Social Security Act with respect to the Medicare Integrity Program and use of recovery audit contractors.

Requires the Secretary to ensure that recovery audit contracts include certain mandatory terms and conditions pertaining to: (1) penalties for certain compliance failures, (2) penalties for overturned appeals, (3) postpayment and prepayment audits, and (4) guidelines for prepayment review.

Directs the Secretary to publish on the Internet website of the Centers for Medicare & Medicaid Services information on recovery audit contractor performance regarding: (1) audit rates, denials, and appeals outcomes; and (2) independent performance evaluations.

Deems to be an original claim for Medicare part B (Supplementary Medical Insurance) payment a resubmitted hospital claim for Medicare part A payment for inpatient hospital services which a recovery audit contractor determines: (1) were not medically necessary and reasonable based on the site of service, but (2) would be medically necessary and reasonable in an outpatient setting of the hospital. Requires payment to be made for such a resubmitted claim for all furnished items and services for which payment may be made under Medicare part B.

Deems to be a reopened claim, for purposes of a hospital's ability to resubmit a claim for Medicare payment in timely fashion, any claim that is the subject of an audit by a recovery audit contractor or a Medicare administrative contractor.

Requires contracts for a recovery audit contractor to require that a physician review each denial of a claim for medical necessity made by an employee of the contractor who is not a physician.

Subjects to administrative and judicial review the Secretary's compliance with guidelines for reopening and revising benefit determinations.