Oncology & Hematology Coding Alert

Question: What diagnosis code should I use for immunotherapy-induced pneumonitis, which was brought on due to the patient taking prescribed Keytruda? Does the code selection differ if the provider’s notes read, “immunotherapy induced pneumonititis” or “chemotherapy induced pneumonitis?”

AAPC Forum Participant

Answer: According to AHA ICD-10-CM Coding Clinic Volume 6, Number 2 (2019), you’ll need to assign two codes in this situation regardless of whether the provider notes the pneumonitis is induced by immunotherapy or chemotherapy.

You’ll first assign the appropriate code from J70.- (Respiratory conditions due to other external agents). For an acute exacerbation of the pneumonitis, you’ll use J70.2 (Acute drug-induced interstitial lung disorders). And if the provider does not specify the status of the condition, you’ll use J70.4 (Drug-induced interstitial lung disorders, unspecified).

Coding caution: The Coding Clinic article reminds you to pay attention to the Excludes1 note that accompanies the J84.- (Other interstitial pulmonary diseases) codes, which tells you that a code such as J84.89 (Other specified interstitial pulmonary diseases) “is not appropriate” because a J70.- code is preferred in this situation.

The Coding Clinic article then instructs you to use a second, appropriate code from T36-T50 (Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances) if the adverse effect is from “a drug that has been correctly prescribed and properly administered.” As Keytruda is immunotherapy, that would lead you to T45.1X5- (Adverse effect of antineoplastic and immunosuppressive drugs). Add the appropriate 7th character to describe the type or timing of the encounter.