Anesthesia Coding Alert

Question: In our practice, we’re still getting used to the intricacies of the ICD-10 diagnosis coding system. The other day, we were debating Z codes. Some of us thought that Z codes could only be used as secondary diagnoses; others contended that Z codes can be primary diagnoses in certain situations. Who’s right?

Missouri Subscriber

Answer: Payers allow you to use Z codes as primary codes when they best represent the main reason a patient is being seen by your provider. So it might not happen too often, but you can use Z codes as primary diagnoses in certain situations.

You’ll most often use Z codes as primary diagnoses when coding aftercare, such as Z47.1 (Aftercare following joint replacement surgery). In this stage of treatment, the primary focus of treatment is normal, routine care following a joint replacement to return the patient’s functional abilities to previous levels.

Z codes should not be used if there is an active or complicated medical diagnosis or a more specific reason for admission.

When you use Z codes as primary diagnoses, you should usually include a secondary ICD-10 code to represent the patient’s primary medical condition (in other words, the reason they are in aftercare). For example, you might report Z96.641 (Presence of right artificial hip joint) as a primary diagnosis along with S72.111D (Displaced fracture of greater trochanter of right femur, subsequent encounter for closed fracture with routine healing).