Overview of thyroid function tests

Thyroid function test is a medical method that uses blood tests to evaluate thyroid hormone levels and related indicators to determine whether the thyroid gland is working normally. The main contents includeThyroid Stimulating Hormone (TSH),Free thyroxine (FT4),Free triiodothyronine (FT3)and other core indicators, supplemented by antibody testing (such as TPOAb, TGAb) to help diagnose autoimmune diseases. The examination is mainly used to screen for diseases such as hyperthyroidism, hypothyroidism, and thyroiditis, and is a common test item in endocrinology departments. You need to fast before the examination and avoid strenuous exercise. Some drugs may interfere with the results and you need to inform your doctor in advance.

Core indicator analysis

The core of thyroid function test isTSH, which is secreted by the pituitary gland and reflects the regulatory status of thyroid hormones. If TSH is abnormal, further testing of FT4 and FT3 is required:Elevated TSH and decreased FT4Suggests primary hypothyroidism,Decreased TSH with elevated FT4It may be hyperthyroidism. In addition,Thyroid peroxidase antibody (TPOAb)Positive is common in Hashimoto's thyroiditis, whileThyroid-stimulating hormone receptor antibody (TRAb)Associated with Graves' disease. The test results need to be comprehensively judged based on symptoms, such as intolerance to cold, fatigue (hypothyroidism) or palpitations and weight loss (hyperthyroidism).

Check indications and precautions

Thyroid function tests are suitable forPatients with suspected thyroid disease(such as neck swelling, sudden weight change),pregnant women(Hypothyroidism affects fetal development) andPeople taking lithium salts or amiodarone for a long time(Drugs may damage the thyroid gland). Required before inspectionFasting for 8-12 hours, to avoid high-fat diet interfering with detection. Some hormonal drugs (such as glucocorticoids) need to be tested after discontinuation, and the specific instructions must be followed. Children and the elderly may need to adjust the reference range due to metabolic differences.

Common diseases and significance of examination

A variety of diseases can be diagnosed through thyroid function tests:Hyperthyroidism(TSH↓, FT4↑) requires antithyroid drugs or iodine 131 treatment;Hypothyroidism(TSH↑, FT4↓) Levothyroxine needs to be supplemented;subclinical thyroid disease(Only TSH abnormality) requires regular monitoring. In addition,Thyroid cancer surgeryPatients need long-term follow-up of TSH to adjust the dosage. The examination can also evaluate pituitary function. For example, simultaneous decreases in TSH and FT4 may indicate pituitary disease.

Summary and extension suggestions

Thyroid function test is a key tool in the diagnosis and management of thyroid disease, and the interpretation of results needs to be based on clinical considerations. If any abnormalities are found, it is recommended thatEndocrinology specialist consultation, perform thyroid ultrasound or iodine uptake rate examination if necessary. Healthy people canScreening every 2-3 years, high-risk groups (such as family history, autoimmune diseases) should shorten the interval. Pay attention to a balanced daily intake of iodine to avoid extreme diets that may affect thyroid health.

Citing sources: 1. "Internal Medicine (9th Edition)" (People's Medical Publishing House) 2. American Thyroid Association (ATA) Guidelines 3. Testing equipment manufacturers: Roche, Siemens, Abbott 4. Related products: Roche Cobas series, Abbott Architect TSH test reagent