C4A.1 — Merkel cell carcinoma of eyelid, including canthus

Not billable

Is C4A.1 billable?

No — C4A.1 is a non-billable header code. C4A.1 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 5 billable codes beneath C4A.1.

Billable codes under this header

C4A.1 at a glance

Code	C4A.1
Description	Merkel cell carcinoma of eyelid, including canthus
Billable	No — header code
Code set	ICD-10-CM FY2027
Valid for encounters	October 1, 2026 – September 30, 2027

How is C4A.1 listed in the Alphabetic Index?

These are the routes through the Alphabetic Index that lead to C4A.1. They show the wording a clinician may have documented, which often differs from the Tabular description.

Carcinoma › Merkel cell › canthus (malignant)
Carcinoma › Merkel cell › eyelid, including canthus (malignant)

What codes fall under C4A.1? (3)

How long has C4A.1 existed?

C4A.1 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.