| cfDNA

Circulating free DNA (cfDNA) (also known as cell-free DNA) are degraded DNA fragments released to body fluids such as blood plasma, urine, cerebrospinal fluid, etc. Typical sizes of cfDNA fragments reflect chromatosome particles (~165bp), as well as multiples of nucleosomes, which protect DNA from digestion by apoptotic nucleases.The release of cfDNA into the bloodstream appears by different reasons, including apoptosis, necrosis and NETosis. Its rapidly increased accumulation in blood during tumor development is caused by an excessive DNA release by apoptotic cells and necrotic cells.
 

| 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)	100	50	25	12.5	6.25	3.12	1.56	0
OD	0.17	0.3	0.48	0.72	1.05	1.42	1.91	2.26
Corrected OD

 

| Repeatability

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

| Recovery

The recovery of cfDNA 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)	87-102	97
Plasma(n=8)	92-107	104
Cell Culture Supernates(n=8)	96-111	107

 

| Linearity

Samples were spiked with high concentrations of cfDNA 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 (%)	82-93	88-96	90-110
	Average (%)	90	93	97
1 : 4	Range (%)	89-104	87-110	105-115
	Average (%)	94	98	109