Objective:

To evaluate the effect on the number of aspirates on the diagnostic efficacy of ultrasound-guided fine-needle aspiration cytology (US-FNAC) in thyroid nodules.

Methods:

From June 2015 to June 2018

352 patients were operated US-FNAC and thyroidectomy. Each nodule was aspirated 4 times. Cy

topathologist diagnosed specimen based on The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) on-site. According to the total numbers of aspiration

cytological results were divided into four groups: group A (1st needle)

group B (first 2 needles)

group C (first 3 needles)

and group D (total 4 needles). Yields of US-FNAC were divided into two levels of accuracy and inaccuracy according to the pathological results of paraffin and diagnostic accuracy was calculated separately.

Results:

The sensitivity of group A

B

C

D were 70.8%

85.6%

94.2%

97.8%. The specificity of group A

B

C

D were 55.0%

75.0%

100.0%

100.0%. The accuracy of group A

B

C

D were 69.0%

84.4%

94.9%

98.0%

respectively. The sensitivity

specificity and accuracy of four groups showed statistically significant difference (

P

＜0.001). There were statistically significant differences in 3 parameters between group A

group B and group C (P＜0.008). Group C and D showed no statistically significance (

P

＞0.008).

Conclusion:

The sensitivity

specificity

and accuracy of aspiration increase with the number of needles. However

comprehensively considered

the 3 needles have the highest efficiency of aspiration on the basis of no complications

and can be used as a routine recommendation.