DESCRIPTION

Albumin is one of the main proteins in animal species, which plays a decisive role in the transport of various ions and in maintaining the colloidal osmotic pressure of the blood. Albumin is able to bind to almost all known drugs, as well as many nutraceuticals and toxic substances, largely determining their pharmaco-and toxicokinetics. Albumin is not only passive, but also an active participant of pharmacokinetic and toxicokinetic processes, possessing a number of enzymatic activities. Numerous experiments have shown esterase or pseudoesterase activity of albumin towards a number of endogeneous and exogeneous esters. Due to the free thiol group of Cys34, albumin can serve as a trap for reactive oxygen and nitrogen species, thus participating in redox processes. Glycated albumin makes a significant contribution to the pathogenesis of diabetes and other diseases. The interaction of albumin with blood cells, blood vessels and tissue cells outside the vascular bed is of great importance. Interactions with endothelial glycocalyx and vascular endothelial cells largely determine the integrative role of albumin.

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	726.9	39.6	5.4
2	8	178.7	10.5	5.9
3	8	98.8	3.9	3.9

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	728.4	32.9	4.5
2	16	180.5	10.3	5.7
3	16	98.5	4.1	4.2

RECOVERY

The recovery of mouse Albumin spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Mouse serum	1:512,000,000	90	85-94
	1:1,024,000,000	97	93-104
Urine	1:256,000	99	85-118
	1:512,000	97	92-108

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 mouse serum was initially diluted 1:64,000,000. The urine was initially diluted 1:32,000.)

		Mouse serum	Urine
1:2	Average% of Expected	100	100
	Range (%)	-	-
1:4	Average% of Expected	108	109
	Range (%)	107-109	93-124
1:8	Average% of Expected	97	114
	Range (%)	97-98	92-136
1:16	Average% of Expected	109	99
	Range (%)	99-118	74-124

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant mouse Albumin produced at Sunlong Medical™.