Pathology/Lab Coding Alert

Question: The pathologist extracts an FNA from a left-lobe thyroid nodule. While the patient is still in the operating room, the pathologist examines the FNA specimen and determines the presence of adequate cells for diagnosis. The pathologist then processes the aspirate, examining two direct smear slides and preparing and examining four additional thin layer preparation slides enhanced to remove inflammatory cells. The pathologist processes the remaining aspirate as a cell block and evaluates slides from the block.

The pathologist stains three slides with keratin to evaluate for undifferentiated thyroid cancer. How should we code this?

Georgia Subscriber

Answer: Report 10021 (Fine needle aspiration; without imaging guidance) for the pathologist's work to procure the FNA specimen from the patient's thyroid gland. Use CPT 88172 (Cytopathology, evaluation of fine needle aspirate; immediate cytohistologic study to determine adequacy of specimen[s]) for the pathologist's adequacy check during surgery.

Although the pathologist used enhanced thin layer slide preparation and examined more than five slides from the aspirate, you should only report 88173 (... interpretation and report) for these slides. Don't report 88112 (Cytopathology, selective cellular enhancement technique with interpretation [e.g., liquid-based slide preparation method], except cervical or vaginal) or 88162 (Cytopathology, smears, any other source; extended study involving over 5 slides and/or multiple stains) in addition to 88173.

For the cell block, including the pathologist's exam and interpretation, report 88305 (Level IV - Surgical pathology, gross and microscopic examination, cell block, any source). Because keratin is not part of the routine staining, also code 88342 (Immunohistochemistry [including tissue immunoperoxidase], each antibody) for the three keratin-stained slides. You should list 88342 only once, even though the pathologist examines three keratin slides, because the stain involves a single antibody.