DESCRIPTION

Pentraxin 3 (PTX3), also known as TNF-inducible gene 14 protein (TSG-14), is a member of the pentraxin superfamily which consists of evolutionarily conserved proteins characterized by a structural motif, the pentraxin domain. Pentraxin 3 can be produced by a variety of cell types including endothelial cells, smooth muscle cells, adipocytes, fibroblasts, mononuclear phagocytes, and dendritic cells, and its expression is induced by primary inflammatory signals, such as IL-1, TNF, and microbial moieties. Pentraxin 3 is an acute phase glycoprotein that plays a role in the regulation of innate resistance to pathogens, inflammation, tissue remodeling and repair, female fertility and cancer. Pentraxin 3 is a biomarker for cardiovascular disease. Increased plasma Pentraxin 3 levels have been found in patients with cardiovascular disorders.

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	793.1	49.4	6.2
2	8	176.5	5.6	3.2
3	8	88.5	6.3	7.1

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	782.1	42.5	5.4
2	16	177.2	8.0	4.5
3	16	86.1	5.2	6.0

RECOVERY

The recovery of human Pentraxin 3/TSG-14 spiked to three different levels throughout the range of the assay was evaluated.

Sample Type		Average% of Expected	Range (%)
Human plasma	1:8	101	94-107
	1:16	90	78-107
Cell culture supernatant	1:800	87	87-88
	1:1,600	87	84-91
Saliva	1:4	88	85-93
	1:8	113	86-129
Cell lysate	1:64	82	79-90
	1:128	76	73-79

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 plasma was initially diluted 1:2. The cell culture supernatant was initially diluted 1:100. The cell lysate was initially diluted 1:8.)

		Human plasma(Sample Diluent PT1-ef)	Cell culturesupernatant(Sample Diluent PT4B1)	Saliva(Sample Diluent PT4B1)	Cell lysate(Sample Diluent PT4B1)
1:2	Average% of Expected	100	100	100	100
	Range (%)	-	-	-	-
1:4	Average% of Expected	109	98	117	108
	Range (%)	108-109	95-101	112-123	107-109
1:8	Average% of Expected	103	102	116	112
	Range (%)	92-114	102-103	108-123	110-113
1:16	Average% of Expected	109	82	99	125
	Range (%)	107-111	80-85	75-123	122-129

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Human Pentraxin 3/TSG-14 One-Step ELISA Kit produced at Sunlong Medical™.