serum thyroxine

Thyroxine is a hormone synthesized and secreted by thyroid follicular cells. Its synthesis and secretion are regulated by pituitary thyrotropin (TSH), and the secretion of pituitary thyrotropin is controlled by hypothalamic thyrotropin releasing hormone (TRH). The thyroxine assay can reflect the level of thyroid function and is not affected by iodine-containing foods. It is a basic screening test for thyroid function. In the normal plasma thyroid-binding globulin (TBG) concentration, the diagnostic coincidence rate for healthy people, untreated hyperthyroidism, and hypothyroidism patients is above 96%. Basic Information Specialist classification: growth and development examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: The hemolysis of the specimen can make the measurement result low. If the specimen is left for too long, the measurement will increase. Normal value Newborns 129 ~ 271nmol / L; Infant 90 ~ 194nmol / L; 1 to 5 years old, 94 to 194 nmol/L; 6 to 10 years old 83 to 172 nmol / L; 65 to 155 nmol/L after 10 years of age; 79 to 227 nmol/L 5 months after pregnancy; > 60-year-old male 65 ~ 129nmol / L; Female 71 ~ 135nmol / L. Clinical significance Reduced in hypothyroidism, subacute thyroiditis, renal failure and so on. Elevation is seen in early hyperthyroidism and subacute thyroiditis. Low results may be diseases: high results of hyperthyroidism in the elderly may be diseases: thyroid tumors, elderly patients with hyperthyroidism (1) venous blood is drawn, usually determined by radioimmunoassay. (2) The thyroxine assay results are affected by thyroid-binding globulin (TBG) in the blood. Increased TBG in the blood can increase T4, such as pregnancy, viral hepatitis, patients using perphenazine, estrogen (including female contraceptives). Conversely, TBG in the blood is reduced, and T4 is also reduced, such as nephrotic syndrome, severe liver disease, patients taking androgen, adrenocortical hormone, salicylic acid, and phenytoin. (3) The hemolysis of the specimen can make the measurement result low. If the specimen is left for too long, the measurement will increase. Inspection process Take appropriate amount of venous blood and send it for inspection. Not suitable for the crowd People with reduced hematopoietic function such as leukemia, various anemia, myelodysplastic syndrome, or people with thrombocytopenia should pay attention to blood draw, and should not take more or more blood. Adverse reactions and risks 1. After the blood is drawn, do not press the needle hole to avoid subcutaneous hematoma. If there is a small piece of bruise in the blood, it is slightly tender, please don't panic, you can do hot compress after 24 hours to promote the absorption of blood. The general small amount of congestion will gradually absorb in 3 to 5 days and the color will become lighter and return to normal. 2. After the blood draw, symptoms such as dizziness, vertigo, fatigue, etc. should be immediately supine, drink a small amount of syrup, and then undergo a physical examination after the symptoms are relieved.