| CK-18

Keratin 18 is a type I cytokeratin. It is, together with its filament partner keratin 8, perhaps the most commonly found products of the intermediate filament gene family. They are expressed in single layer epithelial tissues of the body. Mutations in this gene have been linked to cryptogenic cirrhosis. Two transcript variants encoding the same protein have been found for this gene.Keratin 18 is often used together with keratin 8 and keratin 19 to differentiate cells of epithelial origin from hematopoietic cells in tests that enumerate circulating tumor cells in blood.
 

| 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)	10	5	2.5	1.25	0.625	0.312	0.156	0
OD	2.39	1.92	1.56	1.04	0.74	0.47	0.32	0.07
Corrected OD	2.32	1.85	1.49	0.97	0.67	0.4	0.25	-

 

| Repeatability

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

| Recovery

The recovery of Human CK-18 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)	84-101	96
Plasma(n=8)	92-105	102
Cell Culture Supernates(n=8)	96-108	105

 

| Linearity

Samples were spiked with high concentrations of Human CK-18 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