T66

Radiation sickness, unspecified

Not billable — category only FY2026 2025-10-01 → 2026-09-30

Exclusions 9 never code together

T66code

Excludes1

specified adverse effects of radiation, such as:
burns (T20-T31)T20-T31 T20-T31 T20-T31
leukemia (C91-C95)C91-C95 C91-C95 C91-C95
radiation gastroenteritis and colitis (K52.0)K52.0 K52.0 K52.0
radiation pneumonitis (J70.0)J70.0 J70.0 J70.0
radiation related disorders of the skin and subcutaneous tissue (L55-L59)L55-L59 L55-L59 L55-L59
sunburn (L55.-)L55.-L55.-L55.-

Excludes2

Excludes1 — never code together. The excluded condition and this one are mutually exclusive.

Excludes2 — not included here, but the patient may have both. Code both when documented.

7th character 3

A initial encounter

D subsequent encounter

S sequela

Instructional notes 3

Notes

Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.

Use additional code

Index entries leading here 4

Effect, adverse
- radiation (diagnostic) (infrared) (natural source) (therapeutic) (ultraviolet) (X-ray) NOS T66
- ultraviolet (radiation) (rays) NOS T66
- infrared (radiation) (rays) NOS T66
Radiation
- effects NOS T66
- sickness NOS T66
Irradiation effects, adverse T66
Sickness
- radiation T66

Additional references

AHA Coding Clinic® Licence required

Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.

Maps to no condition category in any loaded model.

Presence is a property of the code. Untick a model to hide it everywhere.

Present FY2024–FY2027.