Eurofins Biomnis code

TBG

Synonyms

• Endocrinology
• TBG

Specialty

Biochemistry

Clinical significance

Thyroxine Binding Globulin (TBG) transports the thyroid hormones (all the triiodothyronine and 70% of the thyroxine) in the blood. The levels of TBG available impact directly on the bioavailability of the thyroid hormones. Increased TBG levels lead to increased total hormone and decreased free hormone levels, but this decrease is rapidly compensated when, in response to low levels, the hypothalamus stimulates the thyroid gland to increase its rate of secretion. In the opposite situation, low levels of TBG result in a reduced total thyroid hormone concentration in the blood with a corresponding increase in free hormone.TBG levels may be high in estrogenemia (e.g. in pregnant women, women taking estrogen-based products and in feminizing tumors), hyperproteinemia (e.g. in liver disease and porphyria) and in certain hereditary disorders.Low TBG levels are associated with congenital TBG deficiency, hyperadrenalism, virilizing tumors, acromegaly, nephrotic syndrome, shock and with the response to certain drugs (steroids,corticoides...)

Preanalytics

• 1 mL :
• serum
•   FROZEN
• Freezing within 4 hours

• A tube specifically for this analysis : No

Methodology

Radioimmunoassay

Turnaround time

2 weeks (if dilution/control needed - TAT 4 weeks