Is B40 a billable ICD-10-CM code?

No. B40 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does B40 sit in the tabular list?

Certain infectious and parasitic diseases (A00-B99), in the block Mycoses (B35-B49).

What cannot be coded together with B40?

B40 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

B40

B40 — Blastomycosis

Non-billable headerICD-10-CM

B40 is a non-billable header ICD-10-CM code for blastomycosis. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

Brazilian blastomycosis (B41.-)
keloidal blastomycosis (B48.0)

Other codes that can never be billed with B40

These codes carry an Excludes1 note pointing at B40. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading B40 alone.

J99Respiratory disorders in diseases classified elsewhere

Risk adjustment

B40 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code to one of these instead B40

7 child codes. Green means billable.

Questions about B40

Is B40 a billable ICD-10-CM code?: No. B40 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does B40 sit in the tabular list?: Certain infectious and parasitic diseases (A00-B99), in the block Mycoses (B35-B49).
What cannot be coded together with B40?: B40 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.