Differentiating TRAb-positive painless thyroiditis from Graves’ disease using biochemical and ultrasound findings
Abstract
Differentiating painless thyroiditis (PT) from Graves’ disease (GD) is important for appropriate management. This study evaluated whether thyroid-stimulating hormone (TSH) receptor antibody (TRAb)-positive PT can be differentiated from GD using biochemical and ultrasound findings. This retrospective study included 1,924 patients with thyrotoxicosis associated with PT or GD who visited Kuma Hospital between November 2020 and September 2023. TRAb titers and radioactive iodine uptake (RAIU) or technetium-99m pertechnetate (99mTc) uptake were measured in all patients. Patients were classified into TRAb-positive PT (n = 16), TRAb-negative PT (n = 222), and GD (n = 1,686). Serum alkaline phosphatase (ALP), TSH, free triiodothyronine (FT3)/free thyroxine (FT4) ratio, and thyroid blood flow were analyzed. No significant differences were observed between TRAb-positive and TRAb-negative PT in any single parameter. TRAb-positive PT significantly differed from GD in ALP (mean: 74.6 vs. 111.5 IU/L, p < 0.05), TSH (median: 0.037 vs. 0.007 μIU/mL, p < 0.001), FT3/FT4 ratio (mean: 2.54 vs. 3.30, p < 0.001), and blood flow (mean: 2.11% vs. 11.60%, p < 0.05). A scoring system assigned one point to each parameter—ALP above the upper limit, TSH below the detection limit, FT3/FT4 ratio >3.00, and blood flow >4.00%. None of the patients with TRAb-positive PT scored ≥3, compared with 65.7% of patients with GD. TRAb-positive PT can be differentiated from GD using combined biochemical and ultrasound markers. Our practical scoring system supports clinical decision-making when RAIU is not readily available or contraindicated and may help avoid unnecessary antithyroid therapy.
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BibTeX
@article{furumura2026differentiating,
title = {{Differentiating TRAb-positive painless thyroiditis from Graves’ disease using biochemical and ultrasound findings}},
author = {Yoshiki Furumura and Mitsuru Ito and Itaru Monno and Keitaro Miyamura and Shuji Fukata and Eijun Nishihara and Mitsushige Nishikawa and Akira Miyauchi and Takashi Akamizu},
journal = {Endocrine Journal},
year = {2026},
month = sep,
doi = {10.1507/endocrj.ej26-0047},
url = {https://www.jstage.jst.go.jp/article/endocrj/73/9/73_EJ26-0047/_article},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Differentiating TRAb-positive painless thyroiditis from Graves’ disease using biochemical and ultrasound findings
AU - Yoshiki Furumura
AU - Mitsuru Ito
AU - Itaru Monno
AU - Keitaro Miyamura
AU - Shuji Fukata
AU - Eijun Nishihara
AU - Mitsushige Nishikawa
AU - Akira Miyauchi
AU - Takashi Akamizu
PY - 2026
DA - 2026/09/01
JO - Endocrine Journal
DO - 10.1507/endocrj.ej26-0047
UR - https://www.jstage.jst.go.jp/article/endocrj/73/9/73_EJ26-0047/_article
AB - Differentiating painless thyroiditis (PT) from Graves’ disease (GD) is important for appropriate management. This study evaluated whether thyroid-stimulating hormone (TSH) receptor antibody (TRAb)-positive PT can be differentiated from GD using biochemical and ultrasound findings. This retrospective study included 1,924 patients with thyrotoxicosis associated with PT or GD who visited Kuma Hospital between November 2020 and September 2023. TRAb titers and radioactive iodine uptake (RAIU) or technetium-99m pertechnetate (99mTc) uptake were measured in all patients. Patients were classified into TRAb-positive PT (n = 16), TRAb-negative PT (n = 222), and GD (n = 1,686). Serum alkaline phosphatase (ALP), TSH, free triiodothyronine (FT3)/free thyroxine (FT4) ratio, and thyroid blood flow were analyzed. No significant differences were observed between TRAb-positive and TRAb-negative PT in any single parameter. TRAb-positive PT significantly differed from GD in ALP (mean: 74.6 vs. 111.5 IU/L, p < 0.05), TSH (median: 0.037 vs. 0.007 μIU/mL, p < 0.001), FT3/FT4 ratio (mean: 2.54 vs. 3.30, p < 0.001), and blood flow (mean: 2.11% vs. 11.60%, p < 0.05). A scoring system assigned one point to each parameter—ALP above the upper limit, TSH below the detection limit, FT3/FT4 ratio >3.00, and blood flow >4.00%. None of the patients with TRAb-positive PT scored ≥3, compared with 65.7% of patients with GD. TRAb-positive PT can be differentiated from GD using combined biochemical and ultrasound markers. Our practical scoring system supports clinical decision-making when RAIU is not readily available or contraindicated and may help avoid unnecessary antithyroid therapy.
SN - 1348-4540
SN - 0918-8959
ER -