[Normal 131iodine uptake values at 2 and 24 hours].
BACKGROUND
Radiolabeled iodine uptake is a useful tool in the study of thyroid diseases.


OBJECTIVE
To obtain normal values for 131 Iodine thyroid uptake in healthy volunteers.


METHODS
A total of 105 subjects were included (52 males and 53 females), with a mean age of 45 years (range: 20 to 68, evenly distributed in decades). A questionnaire was applied and a clinical examination was performed to rule out endocrine diseases. Serum TSH and anti-thyroperoxidase antibodies were also measured. The oral 131I dose was 5-10 microCi, and a Thyrad equipment was used for measurements at 2 and 24 h.


RESULTS
Mean global iodine uptake was 5.5%+/-1.8% (range: 2.3-12.0) at 2 h and 16.2+/-4.8% (range: 6.5-30.1) at 24 h. The values at 2 h among women and men were 6.0+/-1.8 and 4.9+/-1.6%, respectively, (p<0.02). At 24 h, the figures were 17.3+/-4.5 and 15.0+/-4.9%, respectively (p=0.01). Compared to their younger counterparts, radioactive iodine uptake was lower among volunteers older than 40 years, at 2 h (5.0+/-1.7 and 6.0+/-1.8, respectively, p<0.02) and at 24 h (14.9+/-4.4 and 17.6+/-4.9%, respectively, p<0.01).


CONCLUSIONS
Normal thyroid uptake values in adults are influenced by gender and age. Normal thyroid iodine uptake values are slightly higher in females. Iodine thyroid uptake values decrease slightly in subjects aged more than 40 years.
González E
Patricio
P
Departamento de Medicina, Hospital Clínico de la Universidad de Chile, Santiago, Chile. pgonzalez@redclinicauchile.cl
Carmona C
Alberto R
AR
Araya Q
A Verónica
AV
Miranda F
Karina
K
Massardo V
Teresa
T
Jiménez R
Beatriz
B
Jaimovich F
Rodrigo
R
Gatica R
Héctor
H
D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007453:Iodide Peroxidase / Q000097:blood; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011877:Radionuclide Imaging; D012016:Reference Values; D013959:Thyroid Diseases / Q000000981:diagnostic imaging*; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000502:physiology; D013972:Thyrotropin / Q000097:blood*; D013997:Time Factors; D055815:Young Adult
D001323:Autoantibodies; D007457:Iodine Radioisotopes; D013972:Thyrotropin; D007453:Iodide Peroxidase