Physiological Systems (XX) ICD-10-PCS
The XX body system covers New Technology procedures on physiological systems, with 54 ICD-10-PCS codes across 3 root operations, 48 of them billable in fiscal year 2026. Each root operation defines a distinct procedural objective, and the info icons show the official definition with a preview of the codes inside.
Root Operations in This Body System 3 operations · 54 codes
| Chars 1–3 | Root Operation | Codes | Billable |
|---|---|---|---|
| XXE | MeasurementDetermining the level of a physiological or physical function at a point in time | 38 | 36 |
| XX2 | MonitoringDetermining the level of a physiological or physical function repetitively over a periodof time | 11 | 9 |
| XXA | AssistanceTaking over a portion of a physiological function by extracorporeal means | 5 | 3 |
The info icon shows the official root operation definition and previews the codes in that range.
About the XX Body System
The ICD-10-PCS root operation Physiological Systems (XX) covers procedures related to assessing or supporting the functions of body systems. Classified under New Technology, this operation focuses on technologies that monitor, assist, or measure physiological functions.
Specifically, Monitoring (code XX2) involves repeatedly determining the level of a physiological or physical function over time, such as continuous heart rhythm tracking. Assistance (code XXA) describes taking over part of a bodily function using extracorporeal methods—for example, mechanical circulatory support devices. Lastly, Measurement (code XXE) refers to determining the level of a physiological function at a specific moment, like a one-time oxygen saturation test. These distinctions allow precise documentation of advanced procedures to assess or support physiological systems in clinical practice using the ICD-10-PCS Physiological Systems codes.
Questions About This Page
How many codes are in the XX body system?
The XX body system contains 54 ICD-10-PCS codes in FY 2026, organized into 3 root operations. 48 of them are billable on inpatient claims.
What is a root operation?
The root operation is the third character of every ICD-10-PCS code and names the objective of the procedure. Drainage takes fluid out, Excision cuts out a portion of a body part, and Resection removes all of one. Picking the right root operation is the central skill of PCS coding, so each one above carries its official CMS definition.
Related References
Source: CMS FY 2026 ICD-10-PCS order file and code tables, effective October 1, 2025 through September 30, 2026.
