Pathology/Lab Coding Alert

Question: The cytology lab performs an exam of a pleural effusion specimen (obtained through thoracentesis). We use a liquidbased slide preparation method, and the exam finds malignant cells. What are the correct procedure and diagnosis codes?

Tennessee Subscriber

Answer: You should report the cytology exam based on the lab method used, and the diagnosis code that confirms the presence of malignant cells in the fluid.

Based on your description, the appropriate procedure code for the service is 88112 (Cytopathology, selective cellular enhancement technique with interpretation [e.g., liquid based slide preparation method], except cervical or vaginal). If the lab used a direct smear or concentration technique, you would choose a different code from the range 88104-88107 (Cytopathology, fluids, washings or brushings, except cervical or vaginal; ...) or 88108 (Cytopathology, concentration technique, smears and interpretation [e.g., Saccomanno technique]).

The appropriate diagnosis code is 511.81 (Malignant pleural effusion) to demonstrate the malignant cells findings. A note with 511.81 tells you to "code first malignant neoplasm, if known," such as 162.2 (Malignant neoplasm of trachea, bronchus and lung; main bronchus). You don't provide any information that would allow you to assign that code.

Keep in mind: A malignant pleural effusion is caused by a cancerous invasion of the pleura. This could be due to cancer within the lung or metastatic disease from any other organ (such as the colon or kidney. You should stick with 511.81, which represents all the information you have.