Background and purpose: Thyroglobulin antibody (TgAb) is often positive in papillary thyroid carcinoma (PTC) patients. This study aimed to investigate the effect of TgAb on radioiodine ablation efficacy in PTC patients. Methods: A total number of 329 PTC patients with no distant metastasis were included and classified into 2 groups ［G1 group (115 U/mL，n=84) and G2 group (115 U/mL

n=245)］

G2 group was further divid

ed into 2 subgroups ［S1 (40 U/mL

n=31) and S2 (40 U/mL

n=214)］

before

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I ablation. The median follow-up time was 24 months after a total or subtotal thyroidectomy and subsequent

131

I ablation. The efficacy in terms of

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I ablation success rates (IBR) between two groups were compared and the influencing factors were analyzed according to criteria posed by 2015 American Thyroid Association Guidelines

then the effect of

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I dose on IBR was also explored. Results: Female and younger age were more prevalent in patients with high TgAb (P0.05). The G1 group presented lower IBR over the G2 group (35.7% vs 72.7%

P=0.000). Moreover

S1 group also presented lower IBR over S2 group (54.8% vs 75.2%

P=0.017)

indicating the adverse effect from high titer TgAb on IBR. No matter high or low dose

the G1 group presented lower IBR (34.1% vs 71.9%

37.2% vs 73.2%; P=0.000). However

IBR did not differ in G1 or G2 group either with high or low dose

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I (P0.05). TgAb was the only adverse indicator correlating with IBR in multi-logistic regression analysis (P=0.018). Conclusion: TgAb could negatively affect

131

I ablation efficacy

while increasing the dose of

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I failed to improve the success rate in such cases.