ICD-10-CM › S00-T88 › T66-T78 › T66 Radiation sickness, unspecified › T66.XXXA

Valid for claims with a date of service in the current code year.

Valid FY2016 onwards.

What has happened to this code

Official coding rules

Published by CDC for FY2027. A rule attached to a category binds every code beneath it, so the rules inherited from this code's ancestors are shown with the code they come from.

Inherited from T66 Radiation sickness, unspecified

Seventh character required

• The appropriate 7th character is to be added to code T66

Excludes1 - never coded here

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

Inherited from the T66-T78 section Other and unspecified effects of external causes (T66-T78)

Code also

• , 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 CDC's index refers to this code

Wording from the official alphabetic index. Much of it appears nowhere in the code description, which is why a search for the everyday phrase so often finds nothing.

• Sickness > radiation
• Radiation > effects NOS
• Radiation > sickness NOS
• Irradiation effects, adverse
• Effect, adverse > infrared NOS
• Effect, adverse > radiation NOS
• Effect, adverse > ultraviolet NOS

Codes in the same group

Code	Description	Status
T66.XXXD	Radiation sickness, unspecified, subsequent encounter	Valid
T66.XXXS	Radiation sickness, unspecified, sequela	Valid