Validity of fine needle aspiration cytology in the diagnosis of thyroid diseases

Abstract

Introduction: Fine needle aspiration cytology (FNAC) is regarded as an important first line investigation for evaluation of thyroid swellings. It has a diagnostic accuracy of over 90% in terms of specificity, sensitivity and predictive values.

Objective: The aim of this study was to determine the validity (specificity, sensitivity positive/negative predictive values) of FNAC in the diagnosis of thyroid diseases.

Methods: FNAC reports and histopathology reports of patients with thyroid diseases, who have undergone surgery, were retrospectively retrieved from data banks in the Department of Pathology, University of Sri Jayewardenepura, from August 2004 to August 2006. In addition a prospective study in patients with thyroid diseases who came to this unit for FNAC from June to September 2006 was carried out. In all the cases the histological diagnosis was compared with the cytological diagnosis and the results were documented and analyzed by using standard statistical methods.

Results: FNAC has an acceptable validity in the diagnosis of thyroid diseases with high specificity (86.74%), sensitivity (84.05%), positive predictive value (84.05%) and negative predictive value (86.74%).

Keywords: thyroid cytology; specificity; sensitivity; positive and negative predictive values.

DOI: 10.4038/jdp.v5i1.2956

Journal of Diagnostic Pathology 2006/07; 5: 19-29