ICD-10-CM T66 is the diagnosis code for Radiation sickness, unspecified. This code falls under the section "Other and unspecified effects of external causes" within Chapter 19 — Injury, poisoning and certain other consequences of external causes (S00-T88). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as T66. They are mutually exclusive:
Understanding where T66 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, T66 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
T66 is the ICD-10-CM diagnosis code for "Radiation sickness, unspecified". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
T66 is located in Section T66-T78 — "Other and unspecified effects of external causes" within Chapter 19 of the ICD-10-CM Tabular List.
Use T66 when the patients documented diagnosis matches "Radiation sickness, unspecified" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Radiation sickness, unspecified is T66.
Yes, T66 can be used as a primary diagnosis code since it is billable and specific.
T66 is in Chapter 19 of the ICD-10-CM Tabular List.
Type 1 Excludes for T66 include: specified adverse effects of radiation, such as:; burns (T20-T31); leukemia (C91-C95) and more.
Yes, T66 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.