Thyroxine (T4)

T4 Antibody

Name	Thyroxine (T4) antibody
Catalog #	R533c3	R534a7		R555a5
Type	Rabbit monoclonal antibody
React Species	Human
Platforms	Chemiluminescent Immunoassay (CLIA)		Immunochromatography assay (ICA)
Platforms	R555a5 (Capture) - R534a7 (Detection) R555a5(Capture) - R533c3 (Detection)		R533c3 (Capture) - R555a5 (Detection) R534a7 (Capture) - R555a5 (Detection)
Purity	Purity>95%, purified by Protein A/G chromatography
Buffer	1 x PBS, pH 7.4
Storage	Aliquot and store at -20°C or lower. Avoid freeze / thaw cycles.

Product Information

Direct Chemiluminescent Immunoassay

Roche assigned fT4/tT4 clinical samples were tested via the R555a5 (Capture)- R534a7 (Detection) pair on direct Chemiluminescent Immunoassay (CLIA) platform with coincidence rate R²>0.96.

fT4 Sample Coincidence Rate

Sample	Concentration (pmol/L)	RLU
1	0.000	3384
2	4.63	225668
3	11.38	516982
4	19.25	865801
5	52.25	2376942
6	102.50	4750644

Table 1. fT4 Clinical comparison analysis data on CLIA

Figure 1. fT4 Standard curve on CLIA

Coincidence Rate

Sample	Concentration (pmol/L)	RLU
1	0.000	3055
2	20.86	229219
3	41.65	422718
4	85.96	893682
5	120.12	1233027
6	302.40	3039924

Table 2. tT4 Clinical comparison analysis data on CLIA

Figure 2. tT4 Standard curve on CLIA

Cross Reactivity

L-T3 at 10000ng/mL was measured via T4 sandwich antibodies (R555a5-R534a7), and the cross-reactivity was 0.0001%.

Time-resolved Fluorescent Immunoassay (TRFIA) platform

Roche assigned fT4/tT4 clinical samples were tested via the R533c3(Capture)-R555a5(Detection) antibody pair on Time-resolved Fluorescent Immunoassay (TRFIA) platform with coincidence rate R²>0.94 .

f/tT3 Sample Coincidence Rate

Figure 3. fT4 Standard curve on TRFIA

Figure 4. tT4 Standard curve on TRFIA

Concentration (ng/mL)	T value	C value	T/C
0	284	32803	0.0087
0.39	890	32014	0.0278
1.56	3512	41290	0.0851
6.25	9084	48322	0.1880
25	17370	62059	0.2799
100	24460	52855	0.4628
400	47693	47258	1.0092

Table 3. T3 Clinical comparison analysis data on TRFIA

Concentration (ng/mL)	T value	C value	T/C
3.2	202	28510	0.0025
16	192	20754	0.0093
80	472	29940	0.0158
400	1103	24880	0.0443
2000	4109	25491	0.1612

Table 4. T3 Cross reactivity data on TRFIA

Clinical Significance to Thyroxine (T4)

Guidelines to thyroid disease diagnosis/treatment and summary of professional consensus

Thyroxine (T4) is a hormone synthesized by thyroid follicle whose molecular weight is 777 Da, and its secretion is mainly regulated by hypothalamus-pituitary-thyroid axis. Under the stimulation of pituitary thyroid-stimulating hormone, thyroglobulin hydrolyzes and releases T4 into the blood. 99.97% of T4 in the blood binds to thyroid-binding globulin or prethyroid-binding protein, and 0.03% exists in free state. The sum of free thyroxine (FT4) and dissociativethyroxine is called total thyroxine (TT4). FT4 and TT4 are commonly measured in clinical diagnosis.

Serum free thyroxine (FT4) detection

Serum free thyroxine is a sensitive indicator of thyroid function in vitro test. It can reflect thyroid function accurately even when the binding affinity and the concentration of plasma thyroxine-binding protein changed under physiological or pathological conditions.

Normal reference value: 10-31 pmol / L

FT4 elevation indicates thyrotoxicosis, exophthalmic hyperthyroidism, painless/subacute/chronic thyroiditis with hyperthyroidism, overusing of thyroid preparations, thyroid hormone resistance syndrome and other diseases. Lower FT4 indicates hypothyroidism (primary), transient-hypothyroidism period of pituitary/painless/subacute thyroiditis, hypoalbuminemia and other diseases.

Serum total thyroxine (TT4) detection

TT4 is the main product secreted by the thyroid gland, and is an indispensable component of the integrity of the hypothalamus-pituitary-thyroid regulatory system. TT4 measurement can be used for the diagnosis of hyperthyroidism, primary and secondary hypothyroidism, as well as monitoring of thyroid stimulating hormone (TSH) inhibition therapy.

Normal reference value: 4.5-12 μg / L

Elevated TT4 indicates hyperthyroidism, acute thyroiditis, subacute thyroid disease, acute hepatitis, obesity, overtaking thyroid hormones or thyroid rich tissues. The decrease of TT4 indicates hypothyroidism, hypopituitarism, hypothalamic lesions, hypercinesia and other diseases.