free thyroxine

Serum free thyroxine is a sensitive indicator of thyroid function in vitro. Even when physiological and pathological conditions cause changes in plasma thyroid binding protein binding and concentration, it is more ready to reflect thyroid function. The binding moiety of triiodothyronine (T3) and tetraiodothyronine (T4) has no biological activity, and its level does not reflect the functional state of the thyroid. Only a small part of it does not bind to the protein and is in a free state. It is called serum free triiodothyronine (FT3) and serum free thyroxine (FT4). The two directly reflect the thyroid function status and are not affected by changes in blood thyroxine-binding globulin concentration and binding force. Basic Information Specialist classification: growth and development check classification: endocrine examination Applicable gender: whether men and women apply fasting: fasting Tips: Use heparin to raise free thyroxine levels. Normal value Free thyroxine (FT4) 10 ~ 31pmol / L. Clinical significance 1, elevated: thyroid poisoning, exophthalmia hyperthyroidism, painless thyroiditis with hyperthyroidism, subacute thyroiditis with hyperthyroidism, thyroid preparations overdose, thyroid receptor refractory, chronic thyroiditis with hyperthyroidism. 2, reduce: hypothyroidism (primary), pituitary or painless subacute thyroiditis transient dysfunction, hypoalbuminemia. Low results may be diseases: pregnancy with hypothyroidism results may be high disease: pregnancy with hyperthyroidism, hyperthyroidism in the elderly, pregnancy with hyperthyroidism, hyperthyroidism in the elderly, hyperthyroidism during pregnancy 1, the use of heparin can increase the level of free thyroxine, the use of lithium salt can reduce the level of free thyroxine. 2, the clinical significance of free thyroxine determination with serum thyroxine determination, but more sensitive, and not affected by the binding protein. Inspection process Operation method: 1. The 8 mm × 40 mm dialysis bag was pre-soaked with 0.1 mol/L nitric acid for 24 h, and rinsed to neutral with distilled water. 2. Fix one end of the dialysis bag with a plastic clip, and take 0.5 ml of the serum to be tested into the dialysis bag. 3. Take 7 ml of penicillin vial and add 4.5 ml of dialysis buffer to each vial. 4. The dialysis bags filled with serum are stacked in a U shape and placed in a bottle containing dialysis buffer. Leave both ends of the dialysis bag in the mouth of the bottle and completely immerse the serum in the liquid. Fix the dialysis bag with a rubber stopper at the mouth of the bottle. 5. Fix the bottle on a special frame. Analyze in a 37 ° C incubator for 16 to 24 hours. Remove the dialysis bag and keep the dialysate in the bottle for testing. 6. Take a 10mm × 75mm plastic tube and add samples and reagents. 7. Add the separating agent, mix well, put at 4 ° C for 20 min, centrifuge (3500r / min 4 ° C) for 15min. The supernatant was decanted into another plastic tube and measured on an automated gamma immunological counter. 8. Draw a standard curve to the standard solution concentration with B/B0%. Serum FT4 concentrations were obtained directly from the standard curve. Not suitable for the crowd 1. Patients who have taken contraceptives, thyroid hormones, steroid hormones, etc., may affect the results of the examination and prohibit patients who have recently taken the drug history. 2, special diseases: patients with hematopoietic function to reduce disease, such as leukemia, various anemia, myelodysplastic syndrome, etc., unless the examination is essential, try to draw less blood. Adverse reactions and risks 1, subcutaneous hemorrhage: due to pressing time less than 5 minutes or blood draw technology is not enough, etc. can cause subcutaneous bleeding. 2, discomfort: the puncture site may appear pain, swelling, tenderness, subcutaneous ecchymosis visible to the naked eye. 3, dizzy or fainting: in the blood draw, due to emotional overstress, fear, reflex caused by vagus nerve excitement, blood pressure decreased, etc. caused by insufficient blood supply to the brain caused by fainting or dizziness. 4. Risk of infection: If you use an unclean needle, you may be at risk of infection.

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