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Thyroid Uptake (T-Uptake) Converter
Thyroid Uptake (T-Uptake), also known as Thyroid Hormone Binding Ratio (THBR), is a blood test that indirectly measures the amount of unsaturated Thyroxine Binding Globulin (TBG) in the serum. It should not be confused with the Radioactive Iodine Uptake (RAIU) scan used in nuclear medicine.
T-Uptake is primarily used to calculate the Free Thyroxine Index (FTI). Laboratories may report T-Uptake as a percentage (%) or as a normalized unitless ratio (THBR). This converter standardizes these values based on the laboratory’s mean normal reference.
Percent (%)
TraditionalExample: 25% to 35%.
Ratio (THBR)
Thyroid Hormone Binding Ratio (normalized to 1.00).
Clinical Context
Clinical Utility: T-Uptake is inversely related to TBG levels.
• High T-Uptake: Indicates Low TBG (e.g., Nephrotic syndrome, Androgens) or Hyperthyroidism.
• Low T-Uptake: Indicates High TBG (e.g., Pregnancy, Estrogens) or Hypothyroidism.
Conversion Logic:
THBR = Patient T-Uptake (%) ÷ Mean Normal T-Uptake (%).
Example: If Patient = 30% and Lab Mean = 30%, THBR = 1.00.
Free Thyroxine Index (FTI): Total T4 × THBR.
Clinical References
How to Use This Converter
Follow these steps to normalize T-Uptake values.
Set Lab Mean
Enter the Mean Normal (%) used by your laboratory. The standard default is usually 30%.
Enter Result
Input the patient’s result in either the Percent (%) or THBR (Ratio) field.
Automatic Calculation
The tool calculates the equivalent value to help in deriving the FTI.
Reset
Use the Clear button to reset all fields, including the mean.
Frequently Asked Questions
No. Radioactive Iodine Uptake (RAIU) scans the thyroid gland’s activity in vivo. T-Uptake is a blood test measuring protein binding.
A normal THBR is typically between 0.8 and 1.2 (centered around 1.0).