C4A
⚠ Non-billable
Merkel cell carcinoma
ICD-10-CM · FY2026 · Neoplasms
Code
C4A
System
ICD-10-CM
Billable
No — use specific code
Effective
FY2026
Chapter
Neoplasms
Source
CMS / CDC NCHS
⚠ Verify before billing. Confirm against the current CMS/NCHS ICD-10-CM files and your payer's rules before claims submission.
Frequently asked questions
What is ICD-10 code C4A?
ICD-10-CM code C4A represents Merkel cell carcinoma. It is a non-billable header code requiring a more specific subcategory in the Neoplasms chapter, effective October 1, 2025 – September 30, 2026.
Is C4A billable?
No. C4A is a non-billable header. Select a more specific subcategory for claims submission.
What chapter is C4A in?
C4A belongs to the Neoplasms chapter (C00–D49) of ICD-10-CM.
Related codes in the C4A category
C4A.0
Merkel cell carcinoma of lip
Billable
C4A.1
Merkel cell carcinoma of eyelid, including canthus
Non-billable
C4A.2
Merkel cell carcinoma of ear and external auricular canal
Non-billable
C4A.3
Merkel cell carcinoma of other and unspecified parts of face
Non-billable
C4A.4
Merkel cell carcinoma of scalp and neck
Billable
C4A.5
Merkel cell carcinoma of trunk
Non-billable
C4A.6
Merkel cell carcinoma of upper limb, including shoulder
Non-billable
C4A.7
Merkel cell carcinoma of lower limb, including hip
Non-billable
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