DIAGNOSTIC RELIABILITY OF BLIND FNAC AND ULTRASOUND GUIDED FNAC USING HISTOPATHOLOGICAL DIAGNOSIS AS THE GOLD STANDARD

Background: thyroid swellings are common clinical problems and it is important to know exact pathology before treating such conditions. Fnac is now a well-established, cheap, reliable and safe first line diagnostic test for the evaluation of diffuse thyroid lesions with the main purpose of confirming benign lesions and thereby, reducing unnecessary surgeries. Ultrasound guided fnac has the potential to reduce inadequacy rates and is regarded as the optimal cytological method for diagnosis. Objective: to compare the results of blind and ultrasound-guided fnac of thyroid swellings and to find out the diagnostic reliability of blind fnac and ultrasound-guided fnac using histological diagnosis as the gold standard. Methods: hundred patients with thyroid swelling who were subjected to blind and ultrasound-guided fnacs and who subsequently underwent surgery over 2 and a half years were studied. Results: ultrasound guided fnac results revealed 64% benign lesions and 29 % of malignant lesions, and blind fnac revealed 54% benign and 20% malignant cases. Histological gold standard diagnosis comprised of 57 % benign and 43 % malignant cases. Sensitivity and specificity of blind fnac as compared to hpe was 91.48% and 87.7%, positive predictive value (ppv) and negative predictive value (npv) was 84.31% and 93.4%,while sensitivity, specificity, ppv and npv of usg guided fnac as compared to hpe was 97.7%, 92%, 89.58% and 98.27% respectively. Conclusion: blind fnac of thyroid swellings is more convenient and cost effective as compared to ultrasound guided fnac. However, the diagnostic yield in ultrasound guided fnac is significantly more in terms of accuracy.ultrasound guided fnac significantly helps in categorising the tbsrtc category i patients and guides there subsequent management.