ICD-10-CM C4A is the diagnosis code for Merkel cell carcinoma. This code falls under the section "Melanoma and other malignant neoplasms of skin" within Chapter 2 — Neoplasms (C00-D49). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Always refer to the official ICD-10-CM Tabular List for complete coding guidelines. Ensure documentation supports the specificity of the code selected. When in doubt, consult a certified medical coder or the latest CMS guidelines.
Understanding where C4A sits in the ICD-10-CM classification helps ensure proper coding:
No, C4A is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
C4A is the ICD-10-CM diagnosis code for "Merkel cell carcinoma". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
C4A is located in Section C43-C44 — "Melanoma and other malignant neoplasms of skin" within Chapter 2 of the ICD-10-CM Tabular List.
C4A has 10 sub-code(s) that provide more specific detail: C4A.0, C4A.1, C4A.2, C4A.3, C4A.4 and more.
Use C4A when the patients documented diagnosis matches "Merkel cell carcinoma" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Merkel cell carcinoma is C4A.
No, C4A is non-billable. Use a more specific sub-code for primary diagnosis billing.
C4A is in Chapter 2 of the ICD-10-CM Tabular List.
Yes, C4A is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.