The Physiological Systems body system is identified by the character “X” in the 2nd character position and grouped within the New Technology 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.
X = New Technology
The 3rd character refers to the root operation or the objective of the procedure.
Determining the level of a physiological or physical function at a point in time