| Cys-C

Cystatin C or cystatin , a protein encoded by the CST3 gene, is mainly used as a biomarker of kidney function. Cystatin C belongs to the type 2 cystatin gene family. It is a potent inhibitor of lysosomal proteinases (enzymes from a special subunit of the cell that break down proteins) and probably one of the most important extracellular inhibitors of cysteine proteases (it prevents the breakdown of proteins outside the cell by a specific type of protein degrading enzymes). It is found in virtually all tissues and body fluids. Recently, it has been studied for its role in predicting new-onset or deteriorating cardiovascular disease.
 

| 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)	20	10	5	2.5	1.25	0.62	0.31	0
OD	2.28	1.79	1.37	1	0.65	0.39	0.26	0.09
Corrected OD	2.19	1.7	1.28	0.91	0.56	0.3	0.17	-

 

| Repeatability

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

| Recovery

The recovery of Rat Cys-C 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

 

| Linearity

Samples were spiked with high concentrations of Rat Cys-C 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 (%)	84-95	88-96
	Average (%)	91	93
1 : 4	Range (%)	89-103	87-108
	Average (%)	94	98