DESCRIPTION

Thymidine kinase 1 (TK1) is a cytosolic enzyme involved in pyrimidine metabolism that catalyzes the addition of a gammaphosphate group to thymidine and in regenerating thymidine for DNA synthesis and DNA damage. Among the four deoxyribonucleoside-specific kinases in mammalian cells, TK1 is the only one with the most restricted substrates specificity. TK1 has been applied as an important biomarker for the diagnosis of various cancers, including breast cancer, esophageal cancer, and lung cancer. TK1 upregulation was indicated as an early event in a study of breast cancer and further studies demonstrated a positive correlation between TK1 and cancer stage.

PRINCIPLE OF THE ASSAY

Sandwich ELISA structure (Detection antibody labeled with biotin) A capture antibody is pre-coated onto the bottom of wells which binds to analyte of interest. A detection antibody labeled with biotin also binds to the analyte. Streptavidin-HRP binds to the biotin. TMB acts as the HRP substrate and the solution color will change from colorless to blue. A stop solution containing sulfuric acid turns solution yellow. The color intensity is proportional to the quantity of bound protein which is measurable at 450 nm with the correction wavelength set at 630 nm.

PRECISION

Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested 20 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 24 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	20	2,484.3	187.0	7.5
2	20	530.4	21.7	4.1
3	20	141.5	8.2	5.8

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	24	2,464.1	193.4	7.9
2	24	538.7	42.8	8.0
3	24	139.4	9.5	6.8

RECOVERY

The recovery of human TK1 spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human serum	1:2	89	82-100
	1:4	92	84-101
Cell culture supernatant	1:2	113	108-120
	1:4	105	91-124

LINEARITY

To assess the linearity of the assay, human serum samples were spiked with high concentrations of human TK1 and diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. Cell culture supernatant was diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay.

		Human serum	Cell culture supernatant
1:2	Average% of Expected	85	100
	Range (%)	77-91	-
1:4	Average% of Expected	95	97
	Range (%)	86-101	92-101
1:8	Average% of Expected	101	100
	Range (%)	89-108	84-114
1:16	Average% of Expected	109	115
	Range (%)	102-115	114-116

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human TK1 produced at Sunlong Medical™.

Ordering & shipping

• Minimum order: 1 kit
• Lead time: varies with order quantity and specifications. Please consult your local distributor or our sales team for confirmation
• Payment: T/T 100% in advance; PayPal; Alibaba Trade Assurance
• Shipping: FedEx / DHL / UPS express; cold-chain packing available on request
• Price: USD, per kit (48T / 96T options available)