T59.894D — Toxic effect of other specified gases, fumes and vapors, undetermined, subsequent encounter
T59.894D is a billable, specific ICD-10-CM code for toxic effect of other specified gases, fumes and vapors, undetermined, subsequent encounter. It is valid for submission on a claim.
7th character "D" — subsequent encounter
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 T59.894D
These are not written on T59.894D, but they bind it: a note on a category applies to every code beneath it. Billing T59.894D with anything listed here is a denial.
Other codes that can never be billed with T59.894D
These codes carry an Excludes1 note pointing at T59.894D. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading T59.894D alone.
- T71Asphyxiation
Risk adjustment
T59.894D 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.
Medicare coverage
T59.894D is named in 2 Medicare coverage policies — 2 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A56612Billing and Coding: CT of the Head
- A57224Billing and Coding: Respiratory Care
Code history
T59.894D has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.
Related codes at this level
Codes that share T59.894. If T59.894D is not quite right, the correct code is usually one of these.
Questions about T59.894D
- Is T59.894D a billable ICD-10-CM code?
- Yes. T59.894D is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does T59.894D 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 T59.894D?
- T59.894D 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 T59.894D (T59) and apply to it just the same.