Contents
Thyroglobulin (iodine globulin) is a protein produced by thyroid follicles. It is the precursor of thyroid hormones. Two hormones are synthesized from this protein: thyroxine and triiodothyronine. Analysis of thyroglobulin (TG) allows to detect serious diseases of the thyroid gland: carcinoma, thyroiditis, hyperfunction of the thyroid gland, benign adenoma, hypothyroidism, Graves’ disease.
Features of thyroglobulin
The thyroid gland is an internal organ that produces iodoglobulin. In people with a good immune system and in the absence of chronic diseases, it will not be possible to detect protein in the blood plasma, since it remains in the follicles. The content of thyroglobulin in the blood increases when thyroid diseases occur in the body.
TG is used in traditional medicine as a tumor marker. It is needed to control therapy and detect malignant neoplasms in the organ. Some of the formations (follicular and papillary carcinoma) can independently produce a complex protein. With these diseases, doctors are forced to surgically remove the thyroid gland.
Six months after the end of drug therapy, the specialist performs a control assessment of the level of TG in the blood, so an analysis is made for thyroglobulin (venous blood is taken from the patient). If the indicator deviates from the norm upwards, this indicates a recurrence of education.
The cause of an increased level of triglycerides may be injury to the follicle and the ingestion of a large amount of iodoglobulin into the plasma. The analysis will not be particularly informative in patients with thyroid cancer. In the body of a cancer patient, antibodies to thyroglobulin are most often present, so the study will be false negative. The result will also be incorrect if there are other antibodies in the human body, for example, with toxoplasmosis, minonucleosis and cytomegalovirus cholangiopathy.
When is it required to take an analysis for TG?
The specialist prescribes a study to a patient who is diagnosed with thyroid carcinoma, iodine deficiency, Graves’ disease, hypothyroidism. The analysis is done in order to identify metastases or recurrence of neoplasms after the course of treatment. An increased level of iodine globulin indicates a recurrence of formations in the thyroid gland.
The study is needed to determine the effectiveness of radioactive iodine treatment for cancerous tumors of the organ. With the help of analysis, the doctor can diagnose artificial thyrotoxicosis. In young children, thanks to the results of the study, it is possible to identify congenital hyperfunction of the thyroid gland.
Doctors perform this manipulation in order to assess the activity of thyroiditis or to confirm the transferred inflammatory process in the organ. Thyroglobulin acts as a tumor marker and as a method for evaluating the effectiveness of cancer therapy.
Indications and contraindications
There is no danger for manipulation, since the nurse takes blood from the patient with a disposable syringe.
The procedure lasts about one minute and is considered virtually painless. After taking a blood sample, a person should sit on the couch for a couple of minutes and only then go home.
Indications for analysis are:
- congenital hypothyroidism in young children;
- assessment of the patient’s iodine deficiency status;
- diagnosis of artificial thyrotoxicosis;
- monitoring the treatment of various types of thyroid carcinomas;
- thyroiditis.
Side effects and complications after blood sampling in patients, as a rule, are not observed.
Preparing the patient for the procedure and features of blood donation
In order for the results of the study to be accurate and reliable, simple rules should be followed. The patient can take an analysis for TG 3 months after the end of surgical treatment. If a person was treated with radioactive iodine, he should wait at least six months to donate blood. If these deadlines are not observed, the results of the study will be incorrect and there is a possibility that the possibility of recurrence will be shown, when in fact a harmful tumor does not develop.
During the determination of the level of iodoglobulin, a study is carried out for antibodies to the protein. If a large number of antibodies are detected, then the hormone level will be considered low enough. After the abolition of thyroxine for several weeks, the effectiveness of the manipulation will become more reliable, but the doctor must make sure that the patient does not have antibodies to the hormone under study using special tests and diagnostics.
In order for the effectiveness of the study to be without distortion, blood should be taken on an empty stomach in the morning. 24 hours before the procedure, the patient should not go in for sports, 1,5-2 months before the manipulation, it is forbidden to use medicines containing iodine and hormones.
Manipulation is carried out in the treatment room. The patient sits on the couch while the nurse examines the veins in his arms. The patient’s forearm is clamped with a special tourniquet, the place where the needle will be inserted is lubricated with a cotton pad previously moistened with ethyl alcohol. The specialist pierces a vein with a hollow needle and the biomaterial is taken into a flask or other sterile container.
The resulting sample is placed in a test tube and a smear is made on the glass. The biomaterial can be sent to the laboratory, and the patient is applied cotton wool with alcohol to the needle insertion site, fixed with a plaster on top. The patient should hold his hand tightly and not move it for 5 to 10 minutes to avoid bleeding and bruising on the skin.
Norm and deviation from it
The normal level of thyroglobulin in blood plasma is 1,6-59 ng/ml. Antibodies must be less than 4,1 IU/ml. The results obtained may show an increased or decreased protein value, therefore, a qualified endocrinologist should deal with the decoding of the analysis.
Causes of increased TG in the blood: autoimmune inflammatory processes caused by toxic goiter and various types of thyroiditis; radioactive iodine therapy can cause destruction of thyroid cells and an increase in the content of iodoglobulin in the blood; purulent and inflammatory processes in the thyroid gland; complications caused by excision of an internal organ, surgical interventions, which were accompanied by injury to thyroid cells; destruction of organ tissues in follicular nodes due to laser destruction, radiofrequency ablation, fine needle biopsy, ethanol sclerotherapy, scintigraphy and other procedures.
An increase in the level of the hormone in the blood occurs due to some diseases: chronic thyroiditis; hypothyroidism; diffuse toxic goiter; thyroid cancer; Down syndrome; autoimmune thyroiditis; euthyroid goiter; idiopathic hypothyroidism.
TG as a tumor marker: features and characteristics
An analysis for thyroglobulin is prescribed for patients with follicular and papillary tumors, excised thyroid gland. An increased indicator of iodglobulin indicates negative changes and a possible recurrence of cancer. Patients are examined 3-4 times a year. For cancer patients, thyroglobulin is an oncological marker, since patients simply do not have an internal organ and neoplasms.
If anticancer treatment has gone without complications, the protein level will be less than 2 ng/ml. In people who have not been treated with radioactive iodine therapy, the figure should be about 5 ng / ml. With small amounts of protein in the blood, the patient’s well-being will noticeably improve.