Serum total thyroxine (TT4)

T4 is all produced by the thyroid gland and produces about 80-100 ug per day. 99.96% of the T4 in the serum exists in the form of protein binding, 90% of which binds to thyroid hormone binding globulin (TBG), and TT4 measures the hormone that binds to the protein, so the amount of serum TBG and protein and hormone binding Changes will affect the results of the assay. Pregnancy, estrogen, acute viral hepatitis, and congenital factors can cause elevated TBG, leading to an increase in TT4; androgen, glucocorticoids, hypoproteinemia, and innate factors can cause a decrease in TBG, resulting in a decrease in TT4. TT4 increased when hyperthyroidism. Serum total thyroxine is a common indicator for judging hyperthyroidism (commonly known as "hyperthyroidism") or hypothyroidism (commonly known as "hypothyroidism"), and has application value for disease severity assessment and efficacy monitoring. Basic Information Specialist classification: growth and development examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: Before the inspection, you must stop eating foods rich in iodine, such as kelp, seaweed, sea fish and shrimp, etc., depending on the amount of food, stop eating for 2-4 weeks. Normal value The newborn is 130 to 273 nmol/L (10 to 21 μg/dl). Infants 91 to 195 nmol/L (7 to 15 μg/dl). 1 to 5 years old, 95 to 195 nmol/L (7.3 to 15.0 μg/dl). 5 to 10 years old, 83 to 173 nmol/L (6.4 to 13.3 μg/dl). 65 to 156 nmol/L (5 to 12 μg/dl) after 10 years old. 72 to 229 nmol/L (6.1 to 17.6 μg/dl) at 5 months of gestation. >60 years old Male 65 ~ 130nmol / L (5.0 ~ 10.0μg / dl). Female 72 ~ 136nmol / L (5.5 ~ 10.5μg / dl). Clinical significance (1) rise 1 thyroid poisoning painless thyroiditis, subacute thyroiditis, exophthalmia hyperthyroidism, thyroid preparations, teratoma, malignant chorionic epithelioma, pituitary thyroid stimulating hormone tumor. 2 normal thyroid function TBG (thyroid-binding globulin) increase (familial), pregnancy, newborn, part of liver cancer, hepatitis (acute phase), acute intermittent porphyria, drugs (steroids, birth control pills, antithyroid hormone Antibody-positive chronic thyroiditis, familial abnormal albuminemia, T4 pre-albumin (TBPA) hyperactivity, transient hyper-T4emia (acute disease, oral gallbladder contrast agent). (2) lower 1 hypothyroidism chronic thyroiditis, cretinism, iodine organic disorders, pituitary hypothyroidism. 2 normal thyroid function TBG (thyroxine binding globulin) reduction (familial), nephrotic syndrome, artificial dialysis treatment, hypoproteinemia, protein loss gastrointestinal disease, cirrhosis, drugs (testosterone, protein differentiation hormone, Adrenal glucocorticoids, salicylic acid, phenytoin, lenidine, heparin). 3 low T3 syndrome (severe), thyroid poisoning, taking T3 excess. (3) T4 hyperthyroidism (T4 increased and T3 normal). Low results may be diseases: mental disorders associated with hypothyroidism, hyperthyroidism, high results may be diseases: simple goiter in children, thyroid-free cretinism in children, thyroid-related eye disease, endocrine eyeballs, liver - Thyroid syndrome considerations 1. Before the inspection, you must stop eating foods rich in iodine, such as kelp, seaweed, sea fish and shrimp, etc., depending on the amount of food, stop eating for 2 to 4 weeks. 2. The following drugs should be stopped before the examination. According to the dosage and time, stop taking 2~8 weeks. (1), iodine-containing drugs, such as iodide, compound iodine solution, iodine-containing tablets, etc. (2) Drugs that affect thyroid function, such as thyroid tablets and antithyroid drugs. (3) Some Chinese herbal medicines, such as seaweed, kelp, fritillary, burdock, Mutong, etc. 3. The patient should be fasted on the day of the examination. 4. 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 TT4 radioimmunoassay. 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.