Coding Update: An Index Change for Parkinson’s Disease

Coding Update: An Index Change for Parkinson’s Disease

It’s hard to believe, but April 1 is right around the corner. As coders, we know that is one of our update dates, and this year we will get new indexing for Parkinson’s disease you should be aware of. 

We will have a new sub-term, Parkinson’s disease – see Disease, Parkinson’s. We will find this added under the main term “Parkinsonism” in the Alphabetic Index. For those of you who code Parkinson’s disease frequently, this will be a welcome change. Currently, the Alphabetic Index entry of Parkinsonism directs us to code G20.C, Parkinsonism, unspecified.

Coders must follow the Excludes 1 note here to find the code for Parkinson’s disease, NOS G20.A1. 

With this addition comes a change to the Alphabetic Index. The main term, Parkinson’s disease, syndrome or tremor – see Parkinsonism – will be deleted and replaced with two new main terms. The new main terms are Parkinson’s disease and Parkinson’s syndrome or tremor. Main-term Parkinson’s disease instructs coders to see Diseases, Parkinson’s. Main term Parkinson’s syndrome or tremor instructs coders to see Parkinsonism. 

All our updates and changes are important, but this one is particularly significant. Going forward, when a coder is assigning for Parkinson’s disease, they will be directed to G20.A1 from the Alphabetic Index.

As I noted before, previously the Index was directing coders to G20.C. The Excludes 1 note would then instruct coders where to find the correct code. 

This isn’t the only change we have had to Parkinson’s disease recently. In 2023, we had an expansion of our codes noting dyskinesia and fluctuations. Codes G20.A1 and G20.A2 are assigned for Parkinson’s disease without dyskinesia, without and with fluctuations, respectively. Remember here that G20.A1 is our Parkinson’s disease NOS option. Codes G20.B1 and G20.B2 are assigned for Parkinson’s disease with dyskinesia, without and with fluctuations, respectively. 

The Coding Clinic edition for the fourth quarter of 2023 did give us some clarification. It defined dyskinesia as the involuntary movement of the face, arms, legs, or the trunk. In its guidance, Coding Clinic noted that while there is no cure for Parkinson’s disease, levodopa is used to relieve the symptoms. Further defining fluctuations in Parkinson’s disease, Coding Clinic referred to “on” and “off” episodes. In an “on” episode, there is a positive response to the levodopa. In “off” episodes, the response to the levodopa wears off and the Parkinson’s symptoms are seen again. In the Tabular List, our Parkinson’s disease codes are identified as with or without mention of those “off” episodes.   

Coding Clinic notes that Parkinson’s disease is a progressive, neurodegenerative disease, again, with no cure at this time. Parkinson’s disease presents with motor symptoms, including tremors of the hands, arms, legs and feet. Other nonmotor symptoms may be present as well. These may include depression, anxiety, or pain. 

There is a “use additional code” note at G20 instructing us to assign an additional code if applicable to identify dementia or mild neurocognitive disorder due to known physiological condition. Our dementia codes include options for with anxiety, behavioral, mood, or psychotic disturbance, or without any behavioral disturbance. 

Be sure to review the April 2026 update for final changes and guidance.

Facebook
Twitter
LinkedIn

Christine Geiger, MA, RHIA, CCS, CRC

Chris began her health information management career in 1986, working in hospitals and as a consultant. With expertise in ICD-10 coding, audits, and education, she has contributed to compliance reviews and coding programs. She holds a Master's from Washington University, a B.S. from Saint Louis University, and has taught coding at Saint Louis University. Chris is certified in HCC risk-adjusted coding and is active in health management associations.

Related Stories

Lessons Learned: Appealing Audits

The 30th Annual Compliance Institute for the Health Care Compliance Association (HCCA) is scheduled to take place in Orlando next week. If you are there,

Read More

When in Doubt, Ask

Sometimes you want to be contacted by the US Department of Health and Human Services (HHS) Office of Inspector General (OIG).   I realize that

Read More

Leave a Reply

Please log in to your account to comment on this article.

Featured Webcasts

Mastering Breast Biopsy Billing: Guidance-Driven Coding for Accurate Reimbursement

Breast biopsy procedures may be clinically straightforward but accurately translating them into compliant billing can be anything but. In this focused webcast, Shawn Blackburn, CPC, CPMA, CIC, CRC, CCS-P breaks down how imaging guidance, lesion count, laterality, and payer expectations all impact how these procedures should be reported. Through clear explanations and real-world scenarios, you’ll gain practical insight into aligning clinical workflows with billing requirements, avoiding common pitfalls, and ensuring your documentation supports accurate reimbursement and compliance.

May 21, 2026

Mastering OB GYN Coding Accuracy: Precision Coding for Compliance and Reimbursement

Gain clarity and confidence in OB‑GYN coding with this expert‑led webcast featuring Sherri L. Clayton, RHIT, CSS. You’ll learn how to apply global maternity package rules accurately, select the right CPT codes for procedures and visits, and identify documentation gaps that lead to denials. With practical guidance and real examples, this session helps you strengthen compliance, reduce audit risk, and ensure accurate reimbursement for women’s health services.

May 14, 2026

2026 ICD-10-CM/PCS Coding Clinic Update Webcast Series

Uncover essential coding insights with nationally recognized coding authority Kay Piper, RHIA, CDIP, CCS. Through ICD10monitor’s interactive, on‑demand webcast series, Kay walks you through the AHA’s 2026 ICD‑10‑CM/PCS Quarterly Coding Clinics, translating each update into practical, easy‑to‑apply guidance designed to sharpen precision, ensure compliance, and strengthen day‑to‑day decision‑making. Available shortly after each official release.

April 13, 2026

2026 ICD-10-CM/PCS Coding Clinic Update: Fourth Quarter

Uncover critical guidance on the ICD-10-CM/PCS code updates. Kay Piper reviews and explains ICD-10-CM/PCS coding guidelines in the AHA’s fourth quarter 2026 ICD-10-CM/PCS Coding Clinic in an easy to access on-demand webcast.

December 14, 2026

Trending News

Featured Webcasts

Reengineering Utilization Management: Building an Adaptive Model for the New Payer Era

Traditional utilization management models can no longer keep pace with regulatory shifts, payer scrutiny, and operational pressures. In this webcast, Tiffany Ferguson, LMSW, CMAC, ACM, ACPA-C, introduces an Adaptive Model strategy that modernizes UM through role specialization, technology-driven workflows, and proactive, team-based processes. Attendees will learn how to restructure programs to improve efficiency, strengthen clinical collaboration, and enhance financial performance in a rapidly changing healthcare environment.

May 20, 2026

Compliance for the Inpatient Psychiatric Facility (IPF-PPS): Minimizing Federal Audit Findings by Strengthening Best Practices

Federal auditors are intensifying their focus on inpatient psychiatric facilities, using advanced data analytics to spotlight outliers and pursue high‑dollar repayments. In this high‑impact webcast, Michael Calahan, PA, MBA, Compliance Officer and V.P., Hospital & Physician Compliance, breaks down what regulators are really targeting in IPF-PPS admissions, documentation, treatment and discharge planning. Attendees will learn practical steps to tighten processes, avoid common audit triggers and protect reimbursement and reduce the risk of multimillion-dollar repayment demands.

April 9, 2026

Mastering MDM for Accurate Professional Fee Coding

In this timely session, Stacey Shillito, CDIP, CPMA, CCS, CCS-P, CPEDC, COPC, breaks down the complexities of Medical Decision Making (MDM) documentation so providers can confidently capture the true complexity of their care. Attendees will learn practical, efficient strategies to ensure documentation aligns with current E/M guidelines, supports accurate coding, and reduces audit risk, all without adding to charting time.

March 31, 2026

The PEPPER Returns – Risk and Opportunity at Your Fingertips

Join Ronald Hirsch, MD, FACP, CHCQM for The PEPPER Returns – Risk and Opportunity at Your Fingertips, a practical webcast that demystifies the PEPPER and shows you how to turn complex claims data into actionable insights. Dr. Hirsch will explain how to interpret key measures, identify compliance risks, uncover missed revenue opportunities, and understand new updates in the PEPPER, all to help your organization stay ahead of audits and use this powerful data proactively.

March 19, 2026

Trending News

Happy HIP Week! Sign up to win free access to our 2026 Coding Clinic Update Webcast Series! Click here to learn more →

Prepare for the 2025 CMS IPPS Final Rule with ICD10monitor’s IPPSPalooza! Click HERE to learn more

Get 15% OFF on all educational webcasts at ICD10monitor with code JULYFOURTH24 until July 4, 2024—start learning today!

BLOOM INTO SAVINGS! Get 25% OFF during our spring sale through March 27. Use code SPRING26 at checkout to claim this offer.

CYBER WEEK IS HERE! Don’t miss your chance to get 20% off now until Dec. 1 with code CYBER25

CYBER WEEK IS HERE! Don’t miss your chance to get 20% off now until Dec. 2 with code CYBER24