| FT4

Free thyroxine, or FT4, is the physiologically active form of thyroxine (T4). FT4 serves as a sensitive indicator in vitro tests of thyroid function. It can accurately reflect thyroid status even when physiological or pathological conditions alter the binding capacity and concentration of plasma thyroid-binding proteins.
 

| 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 (pmol/L)	64	32	16	8	4	2	1	0
OD	0.216	0.298	0.417	0.669	0.955	1.405	1.79	1.865

 

| Repeatability

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

| Recovery

The recovery of FT4 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)	80-105	97
Plasma(n=8)	91-108	102

 

| Linearity

Samples were spiked with high concentrations of FT4 and diluted with Universal Diluent to produce samples with values within the range of the assay.

 

		Serum(n=4)	Plasma(n=4)
1 : 2	Range (%)	84-98	90-105
	Average (%)	90	93
1 : 4	Range (%)	86-102	87-109
	Average (%)	93	98