h.albumin pincer assay

This Human Albumin Assay kit is to be used for the in vitro quantitative determination of human albumin concentrations in serum, plasma and urine.

Human serum albumin (HSA), 67 kDa, is a non-glycosylated, negatively charged plasma protein synthesized primarily in liver¹. It is the most abundant protein in human plasma and accounts for about 60% of the total serum protein. Serum albumin is important in regulating blood volume by maintaining oncotic pressure. It effectively buffers plasma pH. Albumin also serves as a carrier of hydrophobic molecules, including lipid soluble hormones, bilirubin, bile, calcium, iron^1,2,3. Several low and high affinity ligand binding sites on HSA are responsible for binding of most pharmaceutical drugs⁴. The reference range for albumin concentrations in blood is 30 to 50 mg/mL. It has a serum half-life of approximately 20 days⁵.

Clinically, serum albumin level is used as a prognostic marker for several diseased conditions. Low serum albumin levels are associated with liver damage/ cirrhosis of liver⁶, nephritic syndrome^1,7, inflammation⁸ (early sign of cardiovascular disease) and malnutrition⁹. On the other hand, high albumin levels usually reflect dehydration¹⁰.

In a healthy kidney, albumin's size and negative electric charge exclude it from excretion in the glomerulus. However, in some diseases including diabetic nephropathy, albumin can cross the glomerulus. The lost albumin can be detected by a simple urine test¹¹. Depending on the amount of albumin lost, a patient may have normal renal function, microalbuminuria, or macroalbuminuria.

This Human Albumin Assay is a rapid, homogeneous antibody-based fluorescence assay for detecting human albumin in biological samples. The kit uses two highly specific antibodies recognizing two different epitopes on human albumin protein. The antibodies are conjugated to short fluorophore–labeled complementary single stranded oligonucleotides. Co-association of the two antibodies on albumin protein results in bringing the two complementary single stranded oligonucleotides into proximity, producing a large change of fluorescence signal as a result of fluorescence resonance energy transfer (FRET) between the fluorophores^12,13. The amount of FRET signal is directly proportional to human albumin concentration in the samples. This assay is easy to perform and the whole procedure can be completed within 1 hour.

The following human albumin standard curve was prepared using the Human Albumin Pincer Assay kit. This standard curve is for the purpose of illustration only, and should not be used to calculate unknowns. Each user should obtain his own data and standard curve.

Sensitivity: The minimum detectable concentration of human albumin by this assay is estimated to be 30 ng/ml.

Specificity: The human albumin Pincer^TM Assay Kit is specific to human albumin and will not cross react with various related antigens.

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11. http://www.webmd.com/hw/diabetes_1_2/tu6440.asp
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