4A0004ZMeasurement of Central Nervous Electrical Activity, Open Approach
- Billable / Specific Code
4A0004Z is a billable ICD-10-PCS procedure code for Measurement of Central Nervous Electrical Activity, Open Approach. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The root operation Measurement involves determining the level of a physiological or physical function at a point in time. In AHRQ's Clinical Classifications Software (CCSR), this procedure falls under Electroencephalogram (EEG).
Code Identity
PCS Table Breakdown
Each ICD-10-PCS code is built from seven characters, each an axis of the procedure. Hover or tap the icons for the official CMS definitions.
| Position | Designation | Value | Meaning |
|---|---|---|---|
| 1 | Section | 4 | Measurement and Monitoring |
| 2 | Body System | A | Physiological Systems |
| 3 | Operation | 0 | Measurement |
| 4 | BodySystem | 0 | Central Nervous |
| 5 | Approach | 0 | Open |
| 6 | Function/Device | 4 | Electrical Activity |
| 7 | Qualifier | Z | No Qualifier |
In the ICD-10-PCS Alphabetic Index
These FY 2026 ICD-10-PCS Alphabetic Index entries lead to this code:
To code guidance of the EKG catheter placement, open the FY 2026 ICD-10-PCS Alphabetic Index at Guidance, then the subterms catheter placement, EKG. The index leads to table 4A0, where the approach, Function/Device and qualifier values shown in the breakdown above complete the seven-character code 4A0004Z.
Clinical Classification (CCSR)
AHRQ groups this procedure code into these clinical categories.
Convert to ICD-9-PCS
Closest ICD-9-PCS equivalents for this code under the General Equivalence Mappings.
Similar Procedure Codes
Questions About 4A0004Z
Is 4A0004Z a billable code?
Yes. This is a complete seven-character ICD-10-PCS code, specific enough to report Measurement of Central Nervous Electrical Activity, Open Approach on inpatient claims from October 1, 2025 through September 30, 2026.
What do the characters in 4A0004Z mean?
The code breaks down character by character: the 1st character 4 is the Section (Measurement and Monitoring); the 2nd character A is the Body System (Physiological Systems); the 3rd character 0 is the Operation (Measurement); the 4th character 0 is the BodySystem (Central Nervous); the 5th character 0 is the Approach (Open); the 6th character 4 is the Function/Device (Electrical Activity); the 7th character Z is the Qualifier (No Qualifier).
What is the ICD-9-PCS equivalent of 4A0004Z?
Under the General Equivalence Mappings, Measurement of Central Nervous Electrical Activity, Open Approach crosswalks to ICD-9-PCS 89.14 (Electroencephalogram). The mapping is approximate, so confirm it fits the documentation.
