My name is thyroglobulin, abbreviated as Tg, so please remember my abbreviation. As long as you have a thyroid gland, I must be present in your body, so it is important that you get familiar with me. When many people with thyroid problems go to the hospital for a checkup, the doctor will swish a blood test request form for 7 indicators of thyroid function, and I am among them. In addition to me, there is tetraiodothyronine (T4), triiodothyronine (T3), free T4 and free T3 that are free of binding proteins, thyroid stimulating hormone, and thyroglobulin antibodies that fight me. I originated as a glycoprotein secreted by the thyroid follicular epithelium and usually stay mainly in the thyroid follicular lumen where I am euphoric. One molecule of me usually contains two T4 molecules and half a T3 molecule. The bad guy, the lysosome, separates the T4 and T3 from me on the surface and they leave me and go into the bloodstream, but I sometimes go into the bloodstream less often, and sometimes I go into the lymphatic ducts of the thyroid and then into your bloodstream. Getting into the bloodstream is not so much fun, when I wander to the liver, the macrophages inside the liver will reach out to me and stuff me into its belly, they say this is called clearing ……, really good people! The thyrotropin (TSH) and insulin-like growth factor-1 (IGF-1) in your body are what help me grow and make me and my siblings thrive (stimulate our production); but gamma-interferon, alpha-tumor necrosis factor and retinoids are not so good, they don’t want our family to thrive (inhibit our production). We are a good, docile bunch, and our serum concentrations are stable without circadian or seasonal changes, otherwise you would not have an easy time. We can be found in all normal human serum if the doctor uses a sensitivity assay. Of course, the amount of us in the blood varies from person to person, such as when (1) thyroid size increases, (2) thyroid damage such as biopsy, trauma, bleeding, radiation damage and inflammation, and (3) hormonal effects such as elevated TSH, beta-HCG and TSH receptor antibodies (TRAb). The normal value in serum is 5~40 μg/L. We are also poor, somehow every 65.2 hours, our team will be reduced by half, the doctor said this is our half-life, according to this calculation, if your thyroid gland is removed, about 5~10 days we will plummet to 5~10 μg/L or less. If you have hyperthyroidism caused by a functional adenoma of the thyroid (toxic adenoma hyperthyroidism), subacute thyroiditis, or painless thyroiditis, our serum concentrations will increase, although we will drop if the hyperthyroid patient is taking exogenous thyroid hormone medication (e.g., eugenol). Testing the amount of us in the serum before surgery for differentiated thyroid cancer is of little value for diagnosis because we can be elevated in non-thyroidal thyroid disease, and we can and do act normal in thyroid cancer. Blood Tg levels before surgery for differentiated thyroid cancer are positively correlated with tumor size. After total thyroidectomy for papillary thyroid cancer and follicular carcinoma, our concentration in blood should be <10μg>10μg/L is to tell you to be careful of tumor recurrence or metastasis, please remember my words, it is very accurate, our diagnostic sensitivity is almost 100% and specificity is over 80%, it is good enough, right? After total thyroidectomy and high dose 131-I treatment, if our ingrate TGAb is not present in the serum, you will not be able to detect our presence. When you don’t know if there is thyroid tissue in your body, this is the time to find out by using a TSH stimulation test. This is done by checking our concentration in the blood (basal blood Tg) before TSH stimulation, and then testing our concentration in the blood after using TSH stimulation. If the basal Tg is not measured, it means there is no thyroid tissue; if the basal Tg is positive, but we are not elevated much after TSH stimulation (poor response to TSH), it indicates a poorly differentiated thyroid tumor; if the basal Tg is positive and we are elevated much after TSH stimulation (good response to TSH), it indicates that you have remaining thyroid tissue or a differentiated thyroid cancer is present. Patients with thyroid cancer are usually given levothyroxine T4 (L-T4, or eugenol) to suppress TSH after surgical removal, which is said to inhibit tumor recurrence. When the serum TSH concentration is low, our test value is not sensitive enough to determine tumor recurrence, and the patient needs to be taken off eugenol therapy for a few weeks, and we will check us again when the serum TSH is elevated. There is a more than 10-fold increase in the number of us in the blood of patients with normal thyroid tissue in response to TSH, and it can increase more than 3-fold in patients with well-differentiated thyroid cancer. As I said at the beginning, there is a nemesis of mine inside the blood, it is thyroglobulin antibody (TgAb), once this guy gets on me, I am in trouble, it can kill me, it is more, I will be less. Well, I will introduce myself here today, next time I will come and tell you what I will have after the thermal ablation treatment of thyroid nodules, in short, you should not be too nervous and worried when you see me elevated oh.