OIG’s High‑Risk Diagnosis Toolkit

The Office of Inspector General (OIG) has released a powerful new resource for Medicare Advantage organizations — and it’s one Primary Care practices should pay close attention to.

The Toolkit to Help Decrease Improper Payments in Medicare Advantage Through the Identification of High‑Risk Diagnosis Codes is more than a compliance document. It’s a roadmap for identifying diagnosis codes that are frequently miscoded, poorly documented, or unsupported — and it’s reshaping how payors and providers approach risk adjustment.

Why This Matters

OIG’s audits found that 70% of high‑risk diagnosis codes were not supported in the medical record — and some codes were unsupported over 90% of the time. These gaps lead to improper payments, audit exposure, and downstream compliance risk for both MA plans and the providers who care for their members.

What Primary Care Teams Should Know

Most risk adjustment coding starts in the Primary Care setting. That means:

• Documentation must clearly support the diagnosis — including MEAT elements, chronicity, and linkage to active management.

• Coding must reflect clinical judgment, not assumptions or historical carry‑forward.

• Workflows must prevent over‑coding and under‑coding, both of which create risk.

• Practices must be audit‑ready, with documentation that stands on its own.

What’s Inside the Toolkit

OIG’s toolkit includes:

• Lists of diagnosis codes flagged as high‑risk

• Circumstances that increase miscoding likelihood

• Programming logic used in audits (including SQL queries)

• Guidance for replicating OIG’s methodology internally

It’s designed to help MA organizations — and by extension, their provider partners — proactively identify and correct vulnerable coding patterns.

High-Risk Diagnosis Groups Identified by OIG

These diagnosis categories had the highest error rates in recent audits:

1. Acute Stroke (96% error rate)

2. Acute Heart Attack (95% error rate)

3. Embolism (79% error rate)

4. Lung Cancer (88% error rate)

5. Breast Cancer (96% error rate)

6. Colon Cancer (94% error rate)

7. Prostate Cancer (89% error rate)

8. Potential Mis-Keyed Codes (81% error rate)

These codes were often submitted without supporting documentation, such as inpatient confirmation, relevant procedures, or consistent clinical evidence.

How ProTrust Billing Partners Supports Practices

We help Primary Care teams translate this toolkit into action:

• Chart audits focused on high‑risk codes

• Provider education that’s clear, clinical, and non‑punitive

• Documentation workflows that reduce vulnerability

• Supplemental submissions that are accurate and defensible

Our goal is simple: protect the revenue you’ve earned, reduce audit risk, and build confidence in your coding and documentation processes.