Determination Of Albumin In Serum
By Bromocresol Green Method
By: Dr. Mohammed Golam Rasul
Objectives
To understand the importance of measuring
blood albumin level.
To determine the concentration of albumin in
serum sample by using known standard.
Introduction
Albumin is made in the liver and is responsible for
maintaining proper fluid balances. Decreased
amounts of albumin can occur when the liver is not
making enough or if albumin is being lost through
the kidneys. Increases in albumin do not occur
naturally but can be seen in patients who had
received albumin suspensions.
Functions of Albumin
• Principal functions
– Maintaining fluid balance
– Carrier
– Anti-oxidant activity
– Buffer
Methods of Albumin estimation
1-Precipitation method
2-Electrophoresis
3-Globulin Tryptophan content method
4-Immunochemical methods.
5-Dye binding methods
Types of Samples
• Plasma
Water + solids (e.g. glucose, urea, albumin, fibrinogen)
No cells
• Serum
Serum = plasma – clotting factors
Preparation of sample: Serum
Serum
Venous
Blood
Allow blood to clot
(20min.)
Remove the clot
and centrifuge
Transfer the
clear
supernatant
to specimen
tube
cells
Cent. tube
Determination of Serum albumin
Requirements:
Automatic pipettes
Tips
Cuvettes
 Spectrophotometer
 Reagent
Specimen:
Serum, heparinised or EDTA-plasma
Determination of Serum albumin
Principle:
Bromocresol green with albumin in citrate buffer forms a
colored complex.
The intensity of the color is directly proportional to the
albumin concentration in the sample.
Determination of Serum albumin
Procedure
Blank
Standard
Sample
Determination of Serum albumin
Procedure (kit)
Reagents
Blank
Standard
Sample
Standard (ml)
-
20
-
Sample (ml)
-
-
20
2000
2000
2000
Reagent (mll)
Procedure
Add the reagent, sample & standard according to
instruction.
Mix and let stand at room temperature for 5 min.
Read the absorbance at 630 nm.
Zero the spectrophotometer with the blank reagent.
Read the absorbances of the standard and samples
within 30 min.
Enter the absorbances readings and calculated values in
the table above.
Calculation
Concentration of albumin (g/dl) = Sample Absorbance
Stand. Absorbance
Normal level
3.8 -5.1 g/dl
x 4 g/dl
Clinical Significance
One of the most important serum proteins produced in
the liver is albumin. Variation in albumin from normal
level results malnutrition, Liver diseases ( for example
hepatitis or cirrhosis) skin lesions such as dermatitis and
burns or dehydration. Clinical diagnosis should not be
made on a single test result; it should integrate clinical
and other laboratory data.