Abstract:Objective To analyze the diagnostic value of color Doppler ultrasound, serum hyaluronic alkane synthase 2 (HAS2)， a disintegrin and metalloproteinase domain 9 (ADAM9) and the combination in papillary thyroid microcarcinoma (PTMC). Methods Seventy-four patients who underwent surgical treatment in 910th Hospital of Joint Logistics Support Force from October 2020 to October 2022 and confirmed PTMC by pathological results were selected as the malignant group, and 71 patients with benign thyroid nodules by postoperative pathological results during the same period were selected as the benign group. All patients were examined by color Doppler ultrasound. The levels of serum HAS2 and ADAM9 were detected by enzyme-linked immunosorbent assay (ELISA). Pearson was applied to analyze the correlation between serum HAS2 and ADAM9 in patients with PTMC. The diagnostic value of color Doppler ultrasound, serum HAS2, ADAM9 and their combination in PTMC were evaluated using receiver operating characteristic (ROC) curve. Results There were statistically significant differences between malignant group and benign group in terms of boundary, internal echo, margin, microcalcification, aspect ratio and acoustic halo (P＜0.05). The expression levels of serum HAS2 ［(97.01±21.38) pg/mL vs (66.47±10.29) pg/mL, t=10.886, P＜0.01］ and ADAM9 ［(1.96±0.50) pg/mL vs (1.33±0.28) pg/mL, t=9.308, P＜0.01］ in the malignant group were higher than those in the benign group. Serum levels of HAS2 and ADAM9 in PTMC patients were positively correlated (r=0.516, P＜0.05). The area under the curve (AUC) for diagnosing PTMC using serum HAS2 and ADAM9 was 0.929 and 0.924, respectively. The combination of color Doppler ultrasound, serum HAS2 and ADAM9 had an accuracy of 85.52% and a sensitivity of 95.95% in diagnosing PTMC, which was higher than that of a single detection method. Conclusion Color Doppler ultrasound combined with serum HAS2 and ADAM9 has a high diagnostic value for PTMC, and their combination can improve diagnosis sensitivity.