August 28, 2025

How To Build An ICD-10-PCS Code

AAPC | Certification | Certified Medical Coder | CPC | Medical Coding
By Janine Mothershed

How to Build an ICD-10-PCS Code

ICD-10-PCS (International Classification of Diseases, 10th Revision, Procedure Coding System) is the system used in the United States to code inpatient hospital procedures. Unlike ICD-10-CM, which is used for diagnoses, ICD-10-PCS is specific to procedures performed in the hospital setting. Building an ICD-10-PCS code requires a solid understanding of its structure and logic.

The Structure of an ICD-10-PCS Code

Every ICD-10-PCS code is seven characters long, and each character has a specific meaning:

  • Section – Broad category of the procedure (e.g., Medical and Surgical, Obstetrics, Imaging).

  • Body System – The general body system involved (e.g., cardiovascular, gastrointestinal).

  • Root Operation – The objective of the procedure (e.g., excision, resection, insertion).

  • Body Part – Specific anatomical site where the procedure is performed.

  • Approach – How the procedure is performed (e.g., open, percutaneous, endoscopic).

  • Device – Whether a device is left in place at the end of the procedure (e.g., stent, prosthesis).

  • Qualifier – Provides additional information about the procedure (e.g., diagnostic vs. therapeutic).

How to Build an ICD-10-PCS Code

Identify the Procedure Section

  • Example: Medical and Surgical procedures are always coded in Section 0.

  • Imaging falls under Section B.

Determine the Body System

  • Example: The heart and great vessels are in 2 (Cardiovascular system).

Define the Root Operation

  • This is the most important step. The root operation describes the objective of the procedure:

    • Excision – Cutting out a portion of a body part.

    • Resection – Cutting out an entire body part.

    • Insertion – Putting in a device.

    • Bypass – Altering the route of contents of a tubular body part.

Specify the Body Part

  • ICD-10-PCS identifies very specific locations.

  • Example: Coronary artery, one site; Coronary artery, two sites, etc.

Select the Approach

  • Defines how the procedure was performed:

    • Open

    • Percutaneous

    • Percutaneous Endoscopic

    • Via Natural or Artificial Opening

Identify the Device

  • If a device is left in place, it must be captured.

  • Example: Stent, pacemaker lead, prosthetic joint.

  • If no device remains, this character is usually coded as Z (No device).

Assign the Qualifier

  • Provides extra detail, often unique to the procedure.

  • Example: “Diagnostic” qualifier if the procedure was done for testing purposes.

Example: Coronary Artery Bypass Grafting (CABG)

Procedure: Aorto-coronary artery bypass with one site using autologous vein, open approach.

  • Section (0): Medical and Surgical

  • Body System (2): Heart and Great Vessels

  • Root Operation (1): Bypass

  • Body Part (0): Coronary Artery, One Site

  • Approach (0): Open

  • Device (9): Autologous Vein

  • Qualifier (A): Aorta

Final Code: 021009A

Medical Coding CABG https://codingclarified.com/medical-coding-cabg/

Key Tips for Coders

  • Always read the full operative report. Small details (approach, device, number of sites) change the code.

  • Use the ICD-10-PCS Official Guidelines. They explain when to choose Excision vs. Resection, or how to assign multiple codes.

  • Do not guess. PCS codes are very specific; if documentation is unclear, query the provider.

Bottom Line: ICD-10-PCS codes are built one character at a time, and each character represents a key piece of clinical information. Once you understand the structure, you can confidently construct accurate codes that reflect the procedure performed.

CMS Gov https://www.cms.gov/files/document/icd-10-pcs-2020-tables-and-index-pdf.pdf

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