Iodine | I (24 hour urine)

General Information

Iodine is found in many forms in nature as sodium and potassium inorganic salts, inorganic diatomic iodine molecule and organic monoatomic iodine.

Molecular iodine (I ₂ ) is absorbed from the intestine through active diffusion, while iodine salts are absorbed through the transporter protein (symporter) located in the gastric mucosa.

Iodine is a necessary trace element for the proper functioning of the thyroid gland and the development of the nervous system in children. Accordingly, iodine deficiency is the most frequent cause of widespread endocrine diseases - gout and primary hypothyroidism, as well as retardation of mental development.

Iodine is directly involved in the formation of thyroid hormones. In the basal membrane of the follicles of the thyroid gland there is a transporter protein (symporter) that provides Na ⁺ /I is transported and controlled by thyrotropin-releasing hormone (TSH).

The transporter protein ensures an increase in iodine concentration in follicle cells until its level becomes 20-40 times higher than the serum iodine level. After that, monoatomic iodine I is released ₂with the participation of thyroid peroxidase (TPO) and participates in the formation of the thyroglobulin molecule. The final thyroid hormones are T4 thyroxine and T3 triiodothyronine. 4% of the molecular weight of T65 and 3% of T59 is iodine.

Under normal conditions, 30% of the received iodine is accumulated in the tissue and hormones of the thyroid gland, and the remaining 70% is distributed in the mammary glands, gastric mucosa, eye tissue, and salivary glands. In the cells of these tissues, iodine enters Na + / I symport type transporter protein.

The recommended daily dose of iodine for adults is 150-290 ng. 70 ng per day is enough for the production of hormones by the thyroid gland, however, such a high dose of iodine in the diet is necessary for the lining of the stomach, salivary glands, oral mucosa, skin, thymus (mammary gland) and the choroid plexus of the brain (tissue in the ventricles of the brain, where the head-spinal cord is produced fluid) for proper functioning.

Iodine deficiency develops when the daily intake of iodine is less than 20 ng. This is followed by an increase in the volume of thyroid tissue, or the formation of a goiter, which has a compensatory nature, to maintain the level of hormone production by the gland. Nevertheless, hypothyroidism is often clinically manifested, which can be the cause of anovulation, infertility, pregnancy hypertension, spontaneous abortions and stillbirths in women.

Iodine deficiency, especially in pregnant women, causes deficiency of physical and mental development of the baby, deafness, congenital anomalies of the brain and other organs, congenital hypothyroidism and many other pathologies.

Determination of serum iodine is necessary not only to detect deficiency, but also excess, which may be caused by long-term use of some medications, such as amiodarone.

The chronic toxic effect of iodine develops if the daily dose of iodine exceeds 1.10 nanograms. However, taking too much iodine can suppress the functioning of the gland. Excessive iodine intake can cause a metallic taste in the mouth, excessive salivation, signs of gastrointestinal irritation, acne-like skin lesions, and more.

When is the survey conducted?

• Determination of serum iodine levels in the evaluation of thyroid pathologies
• Monitoring of iodine concentration during treatment with iodine preparations

Preparation of the patient: No prior preparation is required for research

Study material: 24 hours urine

Reference norms

We can judge the concentration of iodine in the body based on the amount of iodine excreted in the urine.

During the administration of gadolinium-containing contrast material, the study of metals and other microelements in the serum should be delayed for at least 48 hours, because gadolinium affects the index.