Question 1

Is T66 a billable ICD-10 code?

Accepted Answer

Yes, T66 is a valid billable ICD-10-CM code for radiation sickness, unspecified. It can be used for medical billing and reimbursement purposes.

Question 2

What does ICD-10 code T66 mean?

Accepted Answer

ICD-10-CM code T66 represents Radiation sickness, unspecified. This code is part of the International Classification of Diseases, 10th Revision, Clinical Modification used for medical coding and billing in the United States.

Question 3

When was ICD-10 code T66 introduced?

Accepted Answer

Code T66 has been part of ICD-10-CM since 2016, when the coding system was mandated for use in the United States. This code was included in the original US implementation.

Question 4

What is the parent category for ICD-10 code T66?

Accepted Answer

The parent category for T66 is section:T66-T78 (Other and unspecified effects of external causes (T66-T78)). This hierarchical classification helps organize related diagnoses for more accurate coding.

Question 5

What conditions are excluded from T66?

Accepted Answer

Code T66 has Type 1 Excludes (mutually exclusive conditions) including: specified adverse effects of radiation, such as:; burns (T20-T31); leukemia (C91-C95) and 4 more conditions. These conditions cannot be coded together with T66 as they represent different diagnoses.

Question 6

Does T66 require a 7th character extension?

Accepted Answer

Yes, T66 requires a 7th character to specify the encounter type. Available extensions include: A (initial encounter), D (subsequent encounter), S (sequela). Use "X" as a placeholder to fill empty positions before the 7th character (e.g., T66XXA for initial encounter). The extension indicates whether this is an initial visit, follow-up, or treatment for a late effect.

T66.XXXS2026

Excludes17Not coded together

Excludes22Not included here

Use Additional Code1Add code for detail

Notes2Additional information

Also Known As7Alternative terms

7th Character Extensions3Encounter type specifiers

Excluded By1Codes that exclude this one