Question 1

What is ICD-10 code S23.8?

Accepted Answer

S23.8 is the ICD-10-CM diagnosis code for Sprain of other specified parts of thorax. It belongs to the ICD-10-CM chapter for injury, poisoning and certain other consequences of external causes (s00-t88). S23.8 is a non-billable header code that organizes more specific child codes; the actual diagnosis on a claim must use one of those children. S23.8 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Question 2

Is S23.8 an HCC code?

Accepted Answer

S23.8 is a non-billable header code, so it cannot itself be a payment HCC. Header codes organize more specific child codes that share the same root concept; one of those children may map to a payment HCC under the CMS-HCC V28 or V24 risk adjustment model. Coders should select a child code from the S23.8 hierarchy that matches the documented presentation, then check that specific child for HCC status.

Question 3

Is S23.8 billable?

Accepted Answer

No. S23.8 is a header (non-billable) ICD-10-CM code. Header codes sit at a higher level of the diagnosis hierarchy and exist to organize a family of more specific child codes. Per ICD-10-CM coding guidelines, a header code cannot be reported on a claim as the diagnosis, coders must select a billable child code from the S23.8 hierarchy that matches the highest level of specificity supported by the provider's documentation. Payers reject header codes submitted as the primary diagnosis.

HCC Buddy Code Card

S23.8

What This Code Means

Child Codes

Code Hierarchy

Open S23.8 in the Interactive Encoder

S23.8 ICD-10-CM Code: Sprain of other specified parts of thorax