4A09X5ZMeasurement of Respiratory Flow, External Approach
- Billable / Specific Code
4A09X5Z is a billable ICD-10-PCS procedure code for Measurement of Respiratory Flow, External 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 Pulmonary function tests.
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 | 9 | Respiratory |
| 5 | Approach | X | External |
| 6 | Function/Device | 5 | Flow |
| 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 measurement of the flow respiratory, open the FY 2026 ICD-10-PCS Alphabetic Index at Measurement, then the subterms Respiratory, Flow. The index leads to table 4A0, where the approach, Function/Device and qualifier values shown in the breakdown above complete the seven-character code 4A09X5Z.
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 4A09X5Z
Is 4A09X5Z a billable code?
Yes. This is a complete seven-character ICD-10-PCS code, specific enough to report Measurement of Respiratory Flow, External Approach on inpatient claims from October 1, 2025 through September 30, 2026.
What do the characters in 4A09X5Z 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 9 is the BodySystem (Respiratory); the 5th character X is the Approach (External); the 6th character 5 is the Function/Device (Flow); the 7th character Z is the Qualifier (No Qualifier).
What is the ICD-9-PCS equivalent of 4A09X5Z?
Under the General Equivalence Mappings, Measurement of Respiratory Flow, External Approach crosswalks to ICD-9-PCS 89.38 (Other nonoperative respiratory measurements). The mapping is approximate, so confirm it fits the documentation.
