Diagnostic Accuracy of Fine Needle Aspiration Cytology (FNAC) in The Diagnosis of Thyroid Nodules at Songkhla Hospital

Abstract

          Background: Thyroid nodules are a common clinical condition, with detection rates ranging from 4% to 76% according to the screening modality. Most thyroid nodules are benign; however, approximately 5–10% may be malignant, making accurate diagnosis essential for appropriate clinical management. Fine-Needle Aspiration Cytology (FNAC) is widely considered the standard initial diagnostic tool for evaluating thyroid nodules. Nevertheless, its diagnostic performance varies across institutions depending on operator expertise, specimen adequacy, and cytopathologist experience, resulting in different predictive values among hospitals. Objective: To evaluate the diagnostic accuracy of FNAC in the assessment of thyroid nodules by comparing cytological findings with histopathological results, the gold standard. Methods: A retrospective descriptive study was conducted using data from patients who received care at Songkhla Hospital between January 1, 2019 and August 31, 2025. Results: A total of 274 patients were included, the majority of whom were female (91.6%), with a mean age of 49.86 years. FNAC demonstrated a sensitivity of 81.36%, specificity of 77.08%, positive predictive value of 68.57%, negative predictive value of 87.06%, and an overall accuracy of 78.71%. The agreement between FNAC and histopathological diagnosis was moderate to substantial (Cohen’s kappa = 0.564). Additionally, solitary nodules and larger nodule size were significantly associated with malignancy. Conclusion: This study supports FNAC as an effective diagnostic tool for screening and guiding treatment planning of patients with thyroid nodules in the context of Songkhla Hospital.