Non-Billable / Non-Specific Code
ICD-10-CM S99.91 is the diagnosis code for Unspecified injury of ankle. This code falls under the section "Injuries to the ankle and foot" within Chapter 19 — Injury, poisoning and certain other consequences of external causes (S00-T88). 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 S99.91 sits in the ICD-10-CM classification helps ensure proper coding:
No, S99.91 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
S99.91 is the ICD-10-CM diagnosis code for "Unspecified injury of ankle". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of S99.91 is S99.9 ("Unspecified injury of ankle and foot"). S99.91 provides a more specific classification within this category.
S99.91 is located in Section S90-S99 — "Injuries to the ankle and foot" within Chapter 19 of the ICD-10-CM Tabular List.
S99.91 has 1918 sub-code(s) that provide more specific detail: A00, A01, A02, A03, A04 and more.
Use S99.91 when the patients documented diagnosis matches "Unspecified injury of ankle" 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 Unspecified injury of ankle is S99.91.
No, S99.91 is non-billable. Use a more specific sub-code for primary diagnosis billing.
S99.91 is in Chapter 19 of the ICD-10-CM Tabular List.
Yes, S99.91 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.