Many physician practices took the OIG recommendation to heart, and do annual compliance audits. There are many questions to answer about audits: how many, how often, internal or external auditor, doing the work under attorney client privilege and whether to do the audits prospectively or retrospectively.
Retrospective audits are audits performed in a physician practice after the claims are submitted to the payer. There are some advantages to this. The practice or auditor can select from a large sample of claims submitted, and use a random number technique to select the claims. This typically results in a large variety of codes selected to audit. The claims have been submitted, so the group doesn't need to hold the claims and delay payment. This type of audit is typically less time sensitive (because claims aren't held) and can be scheduled more easily.
The auditor reviews the medical record and assigns CPT® and ICD-9 codes and modifiers and reviews that the claim is submitted according to coding rules and government regulations. If the audited code differs from the code submitted and that results in the group collecting additional funds, the group must correct and re-submit the claim, refunding the money to the government payer.
Some groups elect to do these audits through their attorney, giving the work product attorney-client privilege.