Radiation sickness, unspecified, sequela

This code signifies the long-term or residual effects of an unspecified radiation sickness. It indicates that the acute phase of radiation exposure has passed, but the patient continues to experience health problems directly attributable to that past event. The specific type or nature of the radiation sickness is not documented.

Use this code when a patient presents with chronic conditions or lasting health issues that are clearly documented as sequelae of a previous, unspecified radiation sickness. This is appropriate for follow-up encounters where the primary focus is managing these persistent effects, rather than the acute radiation injury itself.

• Always look for documentation explicitly stating "sequela of radiation sickness" or similar phrasing.
• Do not use this code for acute radiation sickness; refer to the T66.XXXA or T66.XXXD codes for initial or subsequent encounters of the acute phase.
• Code any specific manifestations of the sequela (e.g., anemia, skin changes, organ damage) in addition to this code.