Albumin is the most abundant plasma protein in human. It accounts for about 60% of the total serum protein. Albumin plays important physiological roles, including maintenance of colloid osmotic pressure, binding of key substances such as long-chain fatty acids, bile acids, bilirubin, haematin, calcium and magnesium. It has anti-oxidant and anticoagulant effects, and also acts as a carrier for nutritional factors and drugs, as an effective plasma pH buffer. Serum albumin is a reliable prognostic indicator for morbidity and mortality, liver disease, nephritic syndrome, malnutrition and protein-losing enteropathies. High levels are associated with dehydration. Simple, direct and automation-ready procedures for measuring albumin concentration in biological samples are becoming popular in Research and Drug Discovery. BioAssay Systems' BCG albumin assay kit is designed to measure albumin directly in biological samples without any pretreatment. The improved method utilizes bromcresol green that forms a colored complex specifically with albumin. The intensity of the color, measured at 620nm, is directly proportional to the albumin concentration in the sample. The optimized formulation substantially reduces interference by substances in the raw samples.

Simple and high-throughput. The procedure involves addition of a single working reagent and incubation for 5 min. Can be readily automated as a high-throughput assay in 96-well plates for thousands of samples per day.

Improved reagent stability and versatility. The optimized formulation has greatly enhanced reagent and signal stability. Cuvet or 96-well plate assay.

No interference in biological samples. No pretreatments are needed. Assays can be directly performed on raw biological samples i.e., in the presence of lipid and protein.

Drug discovery/Pharmacology: effects of drugs on albumin metabolism.

Precautions: reagents are for research use only. Normal precautions for laboratory reagents should be exercised while using the reagents. Please refer to Material Safety Data Sheet for detailed information.

Important: bring reagent to room temperature and shake before use.

1. Dilute standards in distilled water as follows. Dilute serum and plasma samples 2 fold. Transfer 5 μL diluted standards and diluted samples to wells of a clear bottom plate. Store diluted standards at -20°C for future use.

2. Add 200 μL working reagent and tap lightly to mix. Avoid bubble.

3. Incubate 5 min at room temperature and read optical density at 570-670nm (peak absorbance at 620nm).

1. Transfer 20 μL Blank, Standards and samples to appropriately labeled tubes. Add 1000 μL working reagent and tap lightly to mix. Incubate 5 min at room temperature.

2. Transfer to cuvet and read optical density at 620nm.

Important: if sample OD is higher than the OD for standard, dilute samples with distilled water and repeat the assay.

Subtract blank OD (water, #8) from the standard OD values and plot the OD against standard concentrations. Use the standard curve to determine the sample albumin concentration.

Conversions: 0.1 g/dL albumin equals 15 μM, 0.1% or 1000 ppm.

Pipeting devices and accessories (e.g. 5 μL).

Clear bottom 96-well plates (e.g. Corning Costar) and plate reader.

Spectrophotometer and cuvets for measuring OD at 620nm.

Albumin was assayed in duplicate using the 96-well assay protocol. The albumin content (g/dL) was 4.8 ± 0.0 and 5.4 ± 0.0 in human serum and plasma, 2.2 ± 0.0 and 2.8 ± 0.2 in rat serum and plasma, 3.2 ± 0.2 in goat serum and 2.0 ± 0.0 in fetal bovine serum, respectively. Albumin in a fresh healthy human urine sample was below the detection limit (0.01 g/dL).

            Standard Curve in 96-well plate assay

1. Lee, R.H. et al (2006) Multipotent stromal cells from human marrow home to and promote repair of pancreatic islets and renal glomeruli in diabetic NOD_scid mice. PNAS 103 (46): 17438– 17443.

2. Rebecca R. (2006). Associations of histories of depression and PMDD diagnosis with allopregnanolone concentrations following the oral administration of micronized progesterone Psychoneuroendocrinology 31(10):1208-1219.

Albumin is the most abundant plasma protein in human. It accounts for about 60% of the total serum protein. Albumin plays important physiological roles, including maintenance of colloid osmotic pressure, binding of key substances such as long-chain fatty acids, bile acids, bilirubin, haematin, calcium, magnesium. It has anti-oxidant and anticoagulant effects, and also acts as a carrier for nutritional factors and drugs, as an effective plasma pH buffer. Serum albumin is a reliable prognostic indicator for morbidity and mortality, liver disease, nephritic syndrome, malnutrition and protein-losing enteropathies. High levels are associated with dehydration. Simple, direct and automation-ready procedures for measuring albumin concentration in biological samples are becoming popular in Research and Drug Discovery. BioAssay Systems' BCP albumin assay kit is designed to measure albumin directly in biological samples without any pretreatment. The improved method utilizes bromcresol purple that forms a colored complex specifically with albumin. The intensity of the color, measured at 610nm, is directly proportional to the albumin concentrationin the sample. The optimized formulation substantially reduces interference by substances in the raw samples.

Simple and high-throughput. The procedure involves addition of a single working reagent and incubation for 5 min. Can be readily automated as a high-throughput assay for thousands of samples per day.

Improved reagent stability and versatility. The optimized formulation has greatly enhanced reagent and signal stability. Cuvet or 96-well plate assay.

Low interference in biological samples. No pretreatments are needed. Assays can be directly performed on raw biological samples i.e., in the presence of lipid and protein.

Drug Discovery/Pharmacology: effects of drugs on albumin metabolism.

Precautions: reagents are for research use only. Normal precautions for laboratory reagents should be exercised while using the reagents. Please refer to Material Safety Data Sheet for detailed information.

Important: bring reagents to room temperature and shake before use.

1. Dilute standards in distilled water as follows. Dilute serum samples 2 fold. Transfer 20 μL diluted standards and diluted samples to wells of a clear bottom plate. Store diluted standards at -20°C for future use.

2. Add 200 μL working reagent and tap lightly to mix. Avoid bubble formation!

3. Incubate 5 min at room temperature and read optical density at 590-630nm (peak absorbance at 610nm).

1. Transfer 60 μL Blank, Standards and samples to appropriately labeled tubes. Add 1000 μL working reagent and tap lightly to mix. Incubate 5 min at room temperature.

2. Transfer to cuvet and read optical density at 610nm.

Important: if sample OD is higher than the OD for standard, dilute samples in distilled water and repeat the assay.

Subtract blank OD (water, #8) from the standard OD values and plot the OD against standard concentrations. Use the standard curve to determine the sample albumin concentration.

Conversions: 0.1 g/dL albumin equals 15 μM, 0.1% or 1000 ppm.

Pipeting devices and accessories (e.g. 5 μL).

Clear bottom 96-well plates (e.g. Corning Costar) and plate reader.

Spectrophotometer and cuvets for measuring OD at 610nm.

Albumin was assayed in duplicate using the 96-well assay protocol. The albumin content (g/dL) was 3.6 ± 0.0, 2.8 ± 0.1 and 4.3 ± 0.0 in rat serum, fetal bovine serum and goat serum, respectively. The albumin content in a fresh human urine sample was below the detection limit (0.3 g/dL).

1. Maier SM et al (2007) Proteinuria of Nonautoimmune Origin in Wild-type FVB/NJ Mice. Comp Med. 57(3):255-66.

2. Sharifuzzaman SM and Austin B (2009). Kocuria SM1 controls vibriosis in rainbow trout (Oncorhynchus mykiss, Walbaum). J Appl Microbiol. 108(6): 2162 – 2170.