Synonyms
Thyrotropin
Clinical Significance
Screening for thyroid dysfunction and detecting mild (subclinical), as well as overt, primary hypo- or hyperthyroidism in ambulatory patients. Monitoring patients on thyroid replacement therapy.
Confirmation of thyrotropin (TSH, formerly thyroid-stimulating hormone) suppression in thyroid cancer patients on thyroxine suppression therapy.Prediction of thyrotropin-releasing hormone-stimulated TSH response.
Specimen
Serum
Stability
7 days at 4 to 8 °C
30 days at -20 °C
72 hours at ambient temperature
Reference Range
0.27 – 4.2 uIU/ml
Interpretation
| TSH | FREE T4 | FREE OR TOTAL T3 | THYROID FUNCTION |
|---|---|---|---|
| Normal | Normal | Normal | Normal Thyroid Function |
| High | Normal | Normal | Subclinical Hypothyroidism |
| High | Low | Normal or Low | Primary Hypothyroidism related to the Thyroid gland |
| Low or Undetectable | Normal | Normal | Subclinical Hyperthyroidism |
| Low | High | High | Primary Hyperthyroidism related to the Thyroid gland |
| Low | Low | Low or Normal | Secondary Hypothyroidism related to the Pituitary gland |
| Normal or High | High | High | Secondary Hyperthyroidism related to the Pituitary gland |
Limitation
Thyroid-hormone replacement therapy and some drugs may interfere with thyroid function test results. Extreme stress and acute illness may also affect TSH test results, and results may be low during the first trimester of pregnancy.