Evaluation on Adequacy and Diagnostic Comparability of Discarded Residual Materials of Fine-needle Aspirations Processed using ThinprepTM for Lesions on Four Different Organs

Abstract

Objective:The study was to evaluate the adequacy and diagnostic accuracy of discarded residual materials of fine-needle aspirations (FNA) processed using ThinPrep TM on four different organs; breast, thyroid, lymph nodes and salivary glands.Study Designs: Aspirated materials of these lesions were directly smeared on glass slides as routinely done. The needles used were then vigorously rinsed by drawing in the ThinPrep TM medium in order to obtain the needleresidual materials. The direct smears [the gold standard] were reviewed by pathologists on rotation and each was given a diagnosis as per routine testing. The needle-residual material smears [test method] were reviewed separately by one pathologist who was blinded to the diagnoses made.Results: A total of 118 cases comprising 47(39.8%) breasts, 42(35.6%) thyroid, 25(21.2%) lymph node and 4(3.4%) salivary glands lesions were included. The overall diagnostic accuracy of needle-residual materials was comparable to the direct smears materials with overall kappa score of 0.653. Lymph nodes, breast and salivary glands diagnostic accuracy show good agreement (kappa: 0.769, 0.636 and 0.617 respectively). Moderate agreement was seen in thyroid (kappa: 0.569). Conclusion:Residual materials left in needles have sufficient materials for cytological assessment for future molecular studies if needed.