Radiology Coding Alert

Question: A patient diagnosed with stage III lung cancer had a computed tomography (CT) scan of their lungs without contrast to evaluate the size of their tumor. The patient had a chemotherapy session two days prior and experienced vomiting following the treatment.

What ICD-10-CM code(s) do I need to apply?

Virginia Subscriber

Answer: You’ll assign the code for the vomiting first, followed by the adverse effect of chemotherapy code. To report the vomiting, you’ll use R11.10 (Vomiting, unspecified). For the adverse effect of the chemotherapy, you’ll assign T45.1X5A (Adverse effect of antineoplastic and immunosuppressive drugs, initial encounter). Code T45.1X5 carries a 7th character required icon, which means you need to select the correct character to indicate initial encounter (A), subsequent encounter (D), or sequela (S).

Locating the adverse effect code is similar to locating a diagnosis code. However, instead of using the Alphabetic Index, you’ll open the Table of Drugs and Chemicals section in your ICD-10-CM code set. By searching for terms such as “antineoplastic,” “immunosuppressive,” or “cancer chemotherapy drug regimen,” and looking under the column labeled “Adverse effect,” you’ll find the correct code to assign.

Mind the columns: Carefully check the columns in the Table of Drugs and Chemicals to make sure you’re selecting the right code. The first column, labeled “Poisoning, Accidental (unintentional),” will provide the incorrect code. Since the patient’s provider administered the correct drug and dosage, the vomiting is an expected side effect of chemotherapy treatment. However, if the patient received a greater dosage than the doctor prescribed, you could apply code T45.1X1A (Poisoning by antineoplastic and immunosuppressive drugs, accidental (unintentional), initial encounter).

Section I.C.19.e.5.a of the ICD-10-CM guidelines provides instruction on coding adverse effects of prescribed drugs and medication. In this section you’ll find, “When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug (T36-T50). The code for the drug should have a 5th or 6th character ‘5’ (for example T36.0X5-). Examples of the nature of an adverse effect are tachycardia, delirium, gastrointestinal hemorrhaging, vomiting, hypokalemia, hepatitis, renal failure, or respiratory failure.”

Understanding the context is crucial when selecting the correct ICD-10-CM code for an adverse effect. Coding scenarios where the patient experiences adverse effects following chemotherapy can be tricky. Chemotherapy causes several different side effects, including hair loss, fatigue, appetite changes, and nausea and vomiting. Every patient is different and will experience any adverse effects differently. As nausea and vomiting are common side effects of chemotherapy, you’ll code the situation differently if the patient experienced an atypical side effect.