Whether it is a thyroid disease or after thyroid surgery, a blood test for thyroid function is indispensable. However, there are so many items to check thyroid function, and many patients find many high and low arrows on the test report (often indicating abnormal test results), which can scare many patients. In fact, these abnormal test results have different meanings, and many of them don’t need to be worried at all. So what do each of these results mean, and how should they be interpreted for different diseases? The above chart is a common test result report, which basically covers the common test items: 1. T3 and T4 (i.e. triiodothyronine TT3 and tetraiodothyronine TT4): They are products of the thyroid hormone synthesis process and are brothers, with T4 having one more iodine group than T3. Abnormalities in these two results suggest abnormal thyroid function, but they are often not directly related to clinical manifestations, so abnormal T3 and T4 results are not a cause for excessive concern. 2. FT3 and FT4 (free T3 and free T4): Free T4 is the most important hormone for thyroid function, and its abnormalities are often directly related to hyperthyroidism or hypothyroidism, so a high or low FT4 result can directly diagnose hyperthyroidism or hypothyroidism. FT3 is the best brother of FT4, which plays the role of thyroid hormone together with its brother FT4. Based on whether the FT3 and FT4 results are high or low, you can directly determine whether you are hyperthyroid or hypothyroid. TSH is a marker of thyroid function. low TSH indicates imminent hyperthyroidism; high TSH indicates imminent hypothyroidism. 4. Thyroglobulin (Tg): An indicator reflecting the synthetic function of the thyroid gland and the amount of thyroid. It has no special significance in benign disease; for patients with thyroid cancer who have undergone total thyroidectomy, Tg level reflects the presence or absence of recurrence, i.e., the amount of thyroid-derived tissue; Tg below 1, or dynamic change without elevation, does not suggest recurrence. 5, thyroid antibodies (globulin antibodies, peroxidase antibodies): no matter how much they are elevated, it just suggests thyroiditis (Hashimoto’s disease), don’t care about antibody levels, they are not associated with the severity of thyroid disease, moreover, the antibody levels will not drop after treatment, so don’t care too much. To summarize: 1. FT3 and FT4 reflect the functional status of the thyroid gland, as opposed to TSH levels; 2. The level of thyroid antibodies is not related to the degree of disease. How to interpret the thyroid function lab results after thyroid surgery? 1. First of all, it is clear that the main component of Eugenol is FT4, while thyroid tablets contain FT3 and FT4. 2. High FT3 or FT4 will have an effect on the heart after thyroid surgery, regardless of whether the medication is taken or not. It is best not to make these two indicators too high, especially if the patient has a rapid heartbeat at the same time. 3, benign thyroid disease after surgery, the purpose of medication is to maintain thyroid function at normal levels, TSH is the basis for regulating the amount of medication, therefore, high TSH, or FT3/FT4 low, need to supplement eugenol. FT3/FT4 is normal, but TSH is elevated, also suggests that the thyroid function is not enough, need to supplement eugenol. On the contrary, a lower TSH indicates an overdose of the drug and needs to be reduced. 4. TSH needs to be suppressed after thyroid cancer surgery, i.e. the lower the TSH level, the better; therefore, it is necessary to increase Eugenol, and the elevated FT4 will depress TSH; what if Eugenol is increased until the TSH still does not drop after the FT4 is obviously elevated? You can combine thyroid tablets, i.e., elevate FT3 and suppress TSH in synergy with FT4. This is the interpretation of thyroid lab results, and ultimately, you should listen to your doctor’s opinion.