The Physiological Systems body system is identified by the character “A” in the 2nd character position and grouped within the Measurement and Monitoring section of the ICD-10-PCS coding structure. The 2nd character of an ICD-10-PCS code defines the particular body system or general physiological system or anatomical region involved.
4 = Measurement and Monitoring
A- Physiological Systems
B- Physiological Devices
The 3rd character refers to the root operation or the objective of the procedure.