Measurement and Monitoring (4) ICD-10-PCS
Section 4 covers measurement and monitoring procedures with 850 ICD-10-PCS codes across 2 body systems, 844 of them billable in fiscal year 2026. Each body system below lists its root operations and code ranges.
Body Systems in This Section 2 body systems · 850 codes
| Chars 1–2 | Body System | Codes | Billable |
|---|---|---|---|
| 4A | Physiological Systems | 834 | 830 |
| 4B | Physiological Devices | 16 | 14 |
The info icon previews what each row contains.
About Section 4
The characters in the measuring and monitoring section have the following meaning:
- Character 1 = Section
- Character 2 = Physiological System
- Character 3 = Root Operation
- Character 4 = Body System
- Character 5 = Approach
- Character 6 = Function/Device
- Character 7 = Qualifier
Measurement and monitoring section codes represent procedures for determining the level of a physiological or physical function. Measurement and monitoring procedure codes have a first character value of "4". The second character value for body system is either physiological systems or physiological devices. There are two root operations in the measurement and monitoring section, as defined below:
- Measurement: Determining the level of a physiological or physical function at a point in time
- Monitoring: Determining the level of a physiological or physical function repetitively over a period of time
The fourth character specifies the body system measured or monitored. The fifth character specifies approaches as defined in the medical and surgical section. Instead of specifying device, the sixth character specifies the physiological or physical function being measured or monitored. Examples of physiological or physical function values are conductivity, metabolism, pulse, temperature, and volume. If a device used to perform the measurement or monitoring is inserted and left in, then insertion of the device is coded as a separate medical and surgical section procedure. The seventh character qualifier contains specific values as needed to further specify the body part (e.g., central, portal, pulmonary) or a variation of the procedure performed (e.g., ambulatory, stress).
Examples of typical procedures coded in this section are EKG, EEG, and cardiac catheterization. An EKG is the measurement of cardiac electrical activity, while an EEG is the measurement of electrical activity of the central nervous system. A cardiac catheterization performed to measure the pressure in the heart is coded as the measurement of cardiac pressure by percutaneous approach.
Questions About This Page
How many codes are in the 4 section?
The 4 section contains 850 ICD-10-PCS codes in FY 2026, organized into 2 body systems. 844 of them are billable on inpatient claims.
What does section 4 cover?
Section 4 covers measurement and monitoring procedures. The body systems listed above break it into anatomical groups, and each one links to its root operations and code ranges.
Related References
Source: CMS FY 2026 ICD-10-PCS order file and code tables, effective October 1, 2025 through September 30, 2026.
