DESCRIPTION

Fibrinogen is a soluble plasma glycoprotein synthesized in the liver. It is composed of two sets of three structurally different subunits: alpha (FGA), beta (FGB), gamma (FGG). Fibrinogen is converted by thrombin into fibrin during blood coagulation. Fibrinogen and fibrin play overlapping roles in blood clotting, fibrinolysis, cellular and matrix interactions, the inflammatory response, wound healing, and neoplasia. FGA is the alpha chain of fibrinogen. During conversion of fibrinogen to fibrin, fibrinopeptide A is cleaved from FGA by thrombin.

PRINCIPLE OF THE ASSAY

An anti-tag antibody is pre-coated onto the bottom of wells. After adding antigen or samples, Tagged-Capture antibody and HRP-conjugated detection antibody, a sandwich complex is formed in the solution. TMB acts as a HRP substrate, and the solution color will change from colorless to blue. A stop solution containing sulfuric acid turns the 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 8 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 16 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	8	1,634.0	44.5	2.7
2	8	362.2	7.2	2.0
3	8	181.8	7.2	4.0

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	1,637.7	55.0	3.4
2	16	363.0	7.6	2.1
3	16	181.8	6.6	3.6

RECOVERY

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

Sample Type		Average% of Expected	Range (%)
Human serum	1:6,400	98	96-101
	1:12,800	99	96-104
Urine	1:1,280	99	95-103
	1:2,560	100	96-107

LINEARITY

To assess the linearity of the assay, samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. (The human serum was initially diluted 1:800. The urine was initially diluted 1:160.)

		Human serum	Urine
1:2	Average% of Expected	100	100
	Range (%)	-	-
1:4	Average% of Expected	94	96
	Range (%)	93-94	94-99
1:8	Average% of Expected	92	98
	Range (%)	91-94	82-113
1:16	Average% of Expected	90	91
	Range (%)	87-93	83-98

CALIBRATION

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