Japanese
Title血中free triiodothyronineの間接的指標としてのfree T3 indexおよびT3 : TBG比の有用性の比較検討
Subtitle原著
Authors田口英雄*, 萩原康司*, 今野則道*
Authors(kana)
Organization*北海道社会保険中央病院放射線部, 内科
Journal核医学
Volume20
Number6
Page775-783
Year/Month1983/7
Article原著
Publisher日本核医学会
Abstract「要旨」FT3の間接的指標としてのFT3I, T3/TBG比の臨床上の有用性を種々の病態について比較検討した. 対象は正常人40名, 甲状腺機能亢進症26名, 甲状腺機能低下症36名, 正常妊婦16名, 低TBG症5名, 正常T3非甲状腺疾患 (NTI) 10名, 低T3NTI 14名の計147名であった. 対象全体についてのFT3IとFT3, T3/TBG比とFT3との相関係数はそれぞれr=0.98 (p<0.001) , r=0.92 (p<0.001) であった. これらの相関を対象群別にみるとFT3IとFT3, との相関関係は, 低T3NTI以外で有意であり (r=0.67-0.97) , またT3/TBG比とFT3との関係は低TBG症および低T3NTI以外で有意であった (=0.60-0.88) . 各対象群でのFT3とFT3IおよびT3/TBG比との一致度をみると, 甲状腺機能異常では, 両指標ともFT3の分布に一致した. しかし, 高TBG症ではT3/TBG比はFT3を低く, 低TBG症ではT3/TBG比はFT3を高く見積もる傾向を示した. この場合FT3IはFT3の変動に良く一致した. また低T3NTIでは両指標ともFT3の分布に一致しなかった. 以上から 1) 甲状腺機能異常ではFT3I, T3/TBG比のいずれもFT3の間接的指標になり得る. 2) TBG異常症ではFT3Iの方がよりすぐれた指標である. 3) NTI特に低T3NTIでは, いずれの指標もFT3を正しく反映しない. これら3点が結論された.
Practice臨床医学：一般
Keywordsfree T3, free T3 index, T3 : TBG ratio, thyroid status, diagnostic aids
English
TitleA Comparison of Measurements of Serum Free T3 Concentration by Equilibrium Dialysis, Free T3 Index, and T3 : TBG Ratio in Thyroidal and Nonthyroidal Illnesses
SubtitleOriginal Articles
AuthorsHideo TAGUCHI, Koji HAGIWARA, Norimichi KONNO
Authors(kana)
OrganizationDepartment of Radiology, and Internal Medicine, Hokkaido Central Hospital for Social Health Insurance
JournalThe Japanese Journal of nuclear medicine
Volume20
Number6
Page775-783
Year/Month1983/7
ArticleOriginal article
PublisherTHE JAPANESE SOCIETY OF NUCLEAR MEDICINE
Abstract[Summary] The present study was undertaken to examine and compare the methods for measuring free T3 (FT3) by equilibrium dialysis, free T3 index (FT3I) , and T3 : T4-binding globulin (T3/TBG) in euthyroid subjects and in patients with thyroidal and nonthyroidal illnesses (NTI) . We evaluated each test in 40 healthy subjects, 26 patients with hyperthyroidism, 36 patients with hypothyroidism, 16 women in the 3rd trimester of pregnancy, 5 euthyroid subjects with low TBG, and 24 patients with NTI with normal or low serum T3 concentration. Both FT3I and T3/TBG correlated significantly with FT3 (r=0.98, p<0.001, and r=0.92, p<0.001, rerpectively) when the data from all subjects were analyzed together. When each group was analyzed separately, FT3I still correlated significantly with FT3 in all groups (r=0.67-0.97) except in the NTIs with low T3 (r=0.18) . The correlation of T3/TBG with FT3 was also significant in all groups (r=0.60-0.88) other than the euthyroid with low TBG (r=0.32) and NTIs with low T3 (r=0.04) . Both FT3I and T3/TBG values agreed well with the FT3 concentration in hyper-and hypothyroid subjects, whether treated or untreated. In euthyroidism with abnormal TBG concentration, FT3I agreed well with FT3. However, T3/TBG gave a falsely lower FT3 when the TBG level was high, and a falsely higher FT3 when the TBG was low. In NTIs with normal T3, both FT3I and T3/TBG agreed well with FT3, but FT3I and T3/TBG values were all subnormal in NTIs with low T3, where FT3 ranged from normal to subnormal. These data suggest that l) both FT3I and T3/TBG may be equally useful for an assessment of FT3 level in hyper-and hypothyroidism, 2) FT3I may be superior to T3/TBG in euthyroidism with abnormal TBG concentration in serum, 3) neither FT3I nor T3/TBG may be valid for an indirect measure of FT3 in NTIs with low serum concentration of T3.
PracticeClinical medicine
Keywordsfree T3, free T3 index, T3 : TBG ratio, thyroid status, diagnostic aids

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