| TBG

Thyroxine-binding globulin (TBG) is a globulin protein encoded by the SERPINA7 gene in humans. TBG binds thyroid hormones in circulation. It is one of three transport proteins (along with transthyretin and serum albumin) responsible for carrying the thyroid hormones thyroxine (T4) and triiodothyronine (T3) in the bloodstream. Of these three proteins, TBG has the highest affinity for T4 and T3 but is present in the lowest concentration relative to transthyretin and albumin, which also bind T3 and T4 in circulation. Despite its low concentration, TBG carries the majority of T4 in the blood plasma. Due to the very low concentration of T4 and T3 in the blood, TBG is rarely more than 25% saturated with its ligand.
 

| Typical data

As the OD values of the standard curve may vary according to the conditions of the actual assay performance (e.g. operator, pipetting technique, wash technique or temperature effects), the operator should establish a standard curve for each test. Typical standard curve and data are provided below for reference only.

 

Concentration (ng/mL)	50	25	12.5	6.25	3.12	1.56	0.78	0
OD	2.22	1.56	0.92	0.63	0.42	0.25	0.18	0.08
Corrected OD	2.14	1.48	0.84	0.55	0.34	0.17	0.1	-

 

| Repeatability

Intra-assay Precision (Precision within an assay)：CV% < 10%; Inter-assay Precision (Precision between assays)：CV% < 10%
 

| Recovery

The recovery of Human TBG spiked at three different levels in samples throughout the range of the assay was evaluated in various matrices.

 

Sample Type	Range(%)	Average Recovery(%)
Serum(n=8)	83-101	96
Plasma(n=8)	94-105	102
Cell Culture Supernates(n=8)	96-108	106

 

| Linearity

Samples were spiked with high concentrations of Human TBG and diluted with Universal Diluent to produce samples with values within the range of the assay.

 

		Serum(n=4)	Plasma(n=4)	Cell Culture Supernates(n=4)
1 : 2	Range (%)	84-95	88-96	90-110
	Average (%)	91	93	96
1 : 4	Range (%)	89-103	87-108	105-115
	Average (%)	94	98	108