2025 ICD-10-CM Procedure Code 4A00X4Z

Measurement of Central Nervous Electrical Activity, External Approach

ICD-10-PCS Code:: 4A00X4Z
ICD-10-PCS Code for:: Measurement of CNS Electr Activity, Extern Approach
Is Billable?: Yes - Valid for Submission
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4A00X4Z is a billable procedure code used to specify the performance of measurement of central nervous electrical activity, external approach. The code is valid for the year 2025 for the submission of HIPAA-covered transactions. The procedure code involves determining the level of a physiological or physical function at a point in time.

Table of Contents

Code Information
PCS Table
Clinical Classification
Convert to ICD-9-PCS
Other Similar Codes

4A00X4Z PCS Table

In an PCS table each code is represented by up seven alphanumeric characters, with each character in the table respresenting different aspects of the procedure. In the table provided below, each row represents an individual character and includes information about the character's position, designation, label, and procedure notes. For this PCS table the procedure code is in the measurement and monitoring section and is part of the physiological systems body system, classified under measurement operation. The applicable bodysystem for this procedure code is central nervous.

Position	Designation	Character	Label	Procedures Notes
1	Section	4	Measurement and Monitoring
2	Body System	A	Physiological Systems
3	Operation	0	Measurement	Involves: Determining the level of a physiological or physical function at a point in time
4	BodySystem	0	Central Nervous
5	Approach	X	External	Involves: Procedures performed directly on the skin or mucous membrane and procedures performed indirectly by the application of external force through the skin or mucous membrane
6	Function/Device	4	Electrical Activity
7	Qualifier	Z	No Qualifier	Explanation: The value Z is used for the seventh character to indicate that a specific qualifier does not apply to the procedure.

Clinical Classification

Electroencephalogram (EEG)

CCSR Code: MAM011

Clinical Domain: Measurement and Monitoring MAM contains 15 categories that include procedures related to the measurement and monitoring of the function of various organs (e.g., brain, heart) and body systems (e.g., cardiovascular system, respiratory system; excludes fetal measurement and monitoring).

Convert to ICD-9-PCS

Below are the ICD-9=PCS code(s) that most closely match this ICD-10-PCS code, based on the General Equivalence Mappings (GEMs). This ICD-10-PCS to ICD-9-PCS crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

ICD-9-PCS Code

Code: 8914

Approximate Flag: This is an approximate match. The ICD-9-PCS code reflects a close but not exact equivalent of the ICD-10-PCS procedure.

Other ICD-10-PCS Codes Used for Measurement Central Nervous

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What is ICD-10-PCS?

The ICD-10 Procedure Coding System (ICD-10-PCS) is a catalog of procedural codes used by medical professionals for hospital inpatient healthcare settings. The Centers for Medicare and Medicaid Services (CMS) maintain the catalog in the U.S. releasing yearly updates. The 2025 ICD-10-PCS codes are to be used for discharges occurring from October 1, 2024 through September 30, 2025.

Each ICD-10-PCS code has a structure of seven alphanumeric characters and contains no decimals. The first character defines the major "section". Depending on the "section" the second through seventh characters mean different things.