Collection and Handling of Thoracic Small Biopsy and Cytology Specimens for Ancillary Studies: Guideline From the College of American Pathologists in Collaboration With the American College of Chest Physicians, Association for Molecular Pathology, American Society of Cytopathology, American Thoracic Society, Pulmonary Pathology Society, Papanicolaou Society of Cytopathology, Society of Interventional Radiology, and Society of Thoracic Radiology.

CONTEXT.—: The need for appropriate specimen use for ancillary testing has become more commonplace in the practice of pathology. This, coupled with improvements in technology, often provides less invasive methods of testing, but presents new challenges to appropriate specimen collection and handling of these small specimens, including thoracic small biopsy and cytology samples. OBJECTIVE.—: To develop a clinical practice guideline including recommendations on how to obtain, handle, and process thoracic small biopsy and cytology tissue specimens for diagnostic testing and ancillary studies. METHODS.—: The College of American Pathologists convened an expert panel to perform a systematic review of the literature and develop recommendations. Core needle biopsy, touch preparation, fine-needle aspiration, and effusion specimens with thoracic diseases including malignancy, granulomatous process/sarcoidosis, and infection (eg, tuberculosis) were deemed within scope. Ancillary studies included immunohistochemistry and immunocytochemistry, fluorescence in situ hybridization, mutational analysis, flow cytometry, cytogenetics, and microbiologic studies routinely performed in the clinical pathology laboratory. The use of rapid on-site evaluation was also covered. RESULTS.—: Sixteen guideline statements were developed to assist clinicians and pathologists in collecting and processing thoracic small biopsy and cytology tissue samples. CONCLUSIONS.—: Based on the systematic review and expert panel consensus, thoracic small specimens can be handled and processed to perform downstream testing (eg, molecular markers, immunohistochemical biomarkers), core needle and fine-needle techniques can provide appropriate cytologic and histologic specimens for ancillary studies, and rapid on-site cytologic evaluation remains helpful in appropriate triage, handling, and processing of specimens.