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[Normal 131iodine uptake values at 2 and 24 hours]
Patricio González E1, Alberto R Carmona C, A Verónica Araya Q
1Departamento de Medicina, Hospital Clínico de la Universidad de Chile, Santiago, Chile. pgonzalez@redclinicauchile.cl
Insights
Normal radioactive iodine uptake in healthy adults varies by gender and age. Female volunteers showed higher uptake, while those over 40 had slightly lower values, impacting thyroid disease diagnostics.
Area of Science:
- Endocrinology
- Nuclear Medicine
Background:
- Radiolabeled iodine uptake is a critical diagnostic tool for various thyroid conditions.
- Establishing baseline normal values is essential for accurate interpretation of thyroid function tests.
Purpose of the Study:
- To determine the normal range of 131 Iodine thyroid uptake in a healthy adult population.
- To investigate the influence of demographic factors like age and gender on iodine uptake values.
Main Methods:
- 105 healthy volunteers (52 males, 53 females) underwent clinical evaluation and completed a health questionnaire.
- Serum TSH and anti-thyroperoxidase antibodies were measured to exclude endocrine disorders.
- Radioactive iodine (131I) uptake was measured at 2 and 24 hours using Thyrad equipment after oral administration of a 5-10 microCi dose.
Main Results:
- Mean global 131I uptake was 5.5% ± 1.8% at 2 hours and 16.2% ± 4.8% at 24 hours.
- Females exhibited significantly higher uptake than males at both 2 hours (6.0% vs. 4.9%, p<0.02) and 24 hours (17.3% vs. 15.0%, p=0.01).
- Volunteers over 40 years old showed lower uptake compared to younger individuals at 2 hours (5.0% vs. 6.0%, p<0.02) and 24 hours (14.9% vs. 17.6%, p<0.01).
Conclusions:
- Normal thyroid iodine uptake values in adults are significantly influenced by both gender and age.
- Higher uptake in females and a slight decrease in uptake after age 40 are important considerations for clinical interpretation.
- These findings provide updated reference ranges for radioactive iodine uptake, aiding in the diagnosis and management of thyroid diseases.
Background:
Radiolabeled iodine uptake is a useful tool in the study of thyroid diseases.
Aim:
To obtain normal values for 131 Iodine thyroid uptake in healthy volunteers.
Material And 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.
