Oncology & Hematology Coding Alert

Question: What ICD-9 code do I use when a physician treats diarrhea post-chemotherapy?

Georgia Subscriber

Answer: There is no specific ICD-9 code for due to in this case. There are, however, several options. In general, it depends on when the patient was administered chemotherapy. If the patient received it and later developed the diarrhea during the same visit, you would first code the admission for chemotherapy, V58.1 (chemotherapy), as your principal diagnosis and then code the diarrhea 787.91 (diarrhea) and the adverse effect, E933.1 (antineoplastic and immunosuppressive drugs), as your secondary. However, if the patient had the diarrhea on a different visit after receiving the chemotherapy, you would only code 787.91 as your principal and E933.1 as your secondary.

The key component in determining the principal diagnosis is the main reason for the patient visit. The physician must also document that the diarrhea was due to the chemotherapy. If the physician documented the diagnosis as toxic diarrhea or toxic gastroenteritis you would not code the 787.91, but 558.2 (toxic gastroenteritis and colitis). In addition, code E933.1 as secondary.