Question 1

What is ICD-10 code B39?

Accepted Answer

B39 is the ICD-10-CM diagnosis code for Histoplasmosis. It belongs to the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99). B39 is a non-billable header code that organizes more specific child codes; the actual diagnosis on a claim must use one of those children. B39 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 B39 an HCC code?

Accepted Answer

B39 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 B39 hierarchy that matches the documented presentation, then check that specific child for HCC status.

Question 3

Is B39 billable?

Accepted Answer

No. B39 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 B39 hierarchy that matches the highest level of specificity supported by the provider's documentation. Payers reject header codes submitted as the primary diagnosis.

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B39

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B39 ICD-10-CM Code: Histoplasmosis