T66.XXXD — Radiation sickness, unspecified, subsequent encounter
T66.XXXD is a billable, specific ICD-10-CM code for radiation sickness, unspecified, subsequent encounter. It is valid for submission on a claim.
7th character "D" — subsequent encounter
The appropriate 7th character is to be added to code T66
- A
- initial encounter
- D
- subsequent encounter
- S
- sequela
Excludes1 — never code together
These conditions cannot occur together. Billing both on the same encounter is a denial.
Risk adjustment
T66.XXXD 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
T66.XXXD is named in 9 Medicare coverage policies — 9 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A52370Billing and Coding: Bevacizumab and biosimilars
- A55315Billing and Coding: Proton Beam Therapy
- A56612Billing and Coding: CT of the Head
- A56625Billing and Coding: Echocardiography
Related codes at this level
Codes that share T66. If T66.XXXD is not quite right, the correct code is usually one of these.
Questions about T66.XXXD
- Is T66.XXXD a billable ICD-10-CM code?
- Yes. T66.XXXD is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does T66.XXXD sit in the tabular list?
- Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Other and unspecified effects of external causes (T66-T78).
- What cannot be coded together with T66.XXXD?
- T66.XXXD carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.