Is T59.5 a billable ICD-10-CM code?

No. T59.5 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does T59.5 sit in the tabular list?

Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Toxic effects of substances chiefly nonmedicinal as to source (T51-T65).

What cannot be coded together with T59.5?

T59.5 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above T59.5 (T59) and apply to it just the same.

T59.5

T59.5 — Toxic effect of fluorine gas and hydrogen fluoride

Non-billable headerICD-10-CM

T59.5 is a non-billable header ICD-10-CM code for toxic effect of fluorine gas and hydrogen fluoride. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.

This code requires a 7th character

The appropriate 7th character is to be added to each code from category T59

A: initial encounter
D: subsequent encounter
S: sequela

Excludes1 inherited from the categories above T59.5

These are not written on T59.5, but they bind it: a note on a category applies to every code beneath it. Billing T59.5 with anything listed here is a denial.

Written on T59 — Toxic effect of other gases, fumes and vapors

chlorofluorocarbons (T53.5)

Other codes that can never be billed with T59.5

These codes carry an Excludes1 note pointing at T59.5. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading T59.5 alone.

T71Asphyxiation

Risk adjustment

T59.5 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 history

T59.5 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Code to one of these instead T59.5

1 child code. Green means billable.

T59.5XToxic effect of fluorine gas and hydrogen fluoride

Related codes at this level

Codes that share T59. If T59.5 is not quite right, the correct code is usually one of these.

Questions about T59.5

Is T59.5 a billable ICD-10-CM code?: No. T59.5 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does T59.5 sit in the tabular list?: Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Toxic effects of substances chiefly nonmedicinal as to source (T51-T65).
What cannot be coded together with T59.5?: T59.5 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above T59.5 (T59) and apply to it just the same.