T66.XXXD — Radiation sickness, unspecified, subsequent encounter
Is T66.XXXD billable?
Yes, but T66.XXXD is an unspecified code. T66.XXXD is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, T66.XXXD is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting T66.XXXD — the more specific alternatives are listed below.
T66.XXXD at a glance
| Code | T66.XXXD |
|---|---|
| Description | Radiation sickness, unspecified, subsequent encounter |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does T66.XXXD group to?
T66.XXXD sits in MDC 23 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 949Aftercare with CC/MCCmedical
- 950Aftercare without CC/MCCmedical
How is T66.XXXD listed in the Alphabetic Index?
The Alphabetic Index lists these routes under T66, the nearest indexed parent of T66.XXXD. Use them to find the family, then select the specific code.
- Irradiation effects, adverse
- Effect, adverse › infraredNOS
- Effect, adverse › radiationNOS
- Effect, adverse › ultravioletNOS
- Radiation › effects NOS
- Radiation › sickness NOS
- Sickness › radiation
Excludes1 — never code together
The conditions below can never be reported together with T66.XXXD on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes1 — never code together — inherited from T66
The conditions below can never be reported together with T66.XXXD on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Use additional code — inherited from Chapter 19
Report an additional code alongside T66.XXXD to fully describe the condition. T66.XXXD is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of T66.XXXD, but a patient may have both at the same time. When documentation supports it, T66.XXXD and the excluded code may both be reported.
Code also — inherited from T66-T78
Two codes may be needed to describe the condition fully. Whether T66.XXXD is sequenced first depends on the reason for the encounter.
- , if applicable, place of occurrence, such as:
- highway rest stop (Y92.523)
- school (private) (public) (state) as the place of occurrence of the external cause (Y92.21-)
- service areas as the place of occurrence of the external cause (Y92.52-)
- single-family non-institutional (private) house as the place of occurrence of the external cause (Y92.01-)
- transport vehicle as the place of occurrence of the external cause (Y92.81-)
How long has T66.XXXD existed?
T66.XXXD has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.