2. Background
Major Plasma Protein
Half life of 15—20 days
Formation:
Synthesized in the liver as preproalbumin (N-terminal peptide)
Peptide is removed and nascent protein is released from the rough endoplasmic
reticulum
The product, proalbumin, is in turn cleaved in the Golgi vesicles to produce the secreted
albumin.
Released to blood
3. Normal Range
Adults
18 – 60 y 3.5 – 5.5 g/dl
>60 y 3.4 – 4.8 g/dl
Children
14-18 y 3.2-4.5 g/dl
4d-14 y 3.8-5.4 g/dl
Newborns
0-4 day 2.8-4.4 g/dl
4. Functions of Albumin
Maintains Oncotic Pressure
Transports hormones, in particular, ones that are fat-soluble
Transports Fatty Acids ("free" fatty acids) to the liver and to myocytes for utilization
of energy
Transports unconjugated Bilirubin
Transports many Drugs, serum albumin levels can affect the half-life of drugs
Competitively binds ions (Ca2+)
Serum albumin, as acute phase reactant, is a marker of an inflammatory state, is
down regulated.
Prevents photo degradation of Folic Acid
6. Hyper Albuminemia
Causes
Dehydration
Vitamin A deficiency
Treatment
Rehydration
Zn++ supplementation
Note: Hyper Albuminemia is of little to no diagnostic Value in clinical
Practice
7. Hypo Albuminemia
Liver disease i.e Cirrhosis of the liver.
Excess excretion by the Kidneys (Nephrotic Syndrome)
Excess loss in bowel (protein-losing enteropathy, e.g., Ménétrier's disease)
Burns (plasma loss in the absence of skin barrier)
Redistribution (hemodilution increased vascular permeability or decreased lymphatic
clearance)
Acute disease states (referred to as a negative acute-phase protein)
Malnutrition and wasting
Mutation causing analbuminemia (very rare)
8. Effects of Hypo Albuminemia on Body
Edema
Hypotension
Abdominal Distension (Ascites)
Lack of appetite
Muscle Cramps
Fatigue
10. Principle
Measurement of albumin is based on its binding to the indicator dye
bromocresol green (BCG) in pH 4.1
Forms a blue-green colored complex.
The intensity of the blue-green color is directly proportional to the concentration of
albumin in the sample.
It is determined by monitoring light absorbance at 578 nm.
Reaction:
Albumin + BCG -----------Albumin-BCG Complex
11. Requirements
Bromocresol green
Acetate Buffer
Above are mixed and left to stand for 10 mins yields Working Reagent
Standard Solution: Concentration of 4g/dl
12. Precautions
The only acceptable anticoagulants are heparin and EDTA.
Fresh Serum to be obtained for Experiment.
Ideally, after Centrifugation, serum should be immediately separated from blood
cells.
Do not try to ingest or inhale the Bromocresol Solution. In case of contact, wash
thoroughly and seek medical help.
13. Procedure
Take Three Test Tubes and Mark then Unknown(U), Standard(S) and Blank(B).
Take 1ml of Working Reagent in each tube.
Add 10 µl of distilled water into Blank(B).
Add 10 µl of Standard Solution into Test tube marked as Standard(S).
Add 10 µl of Serum into the test tube marked as Unknown(U).
Mix and Incubate for 5 minutes at 20—25 degree Celsius.
Check light absorbance via a calorimeter at 578nm.
Unknown Absorbance
Calculation: Albumin concentration (g/dl) = ------------------------------x 4
Standard Absorbance
14. Limitations
Minimum detectable limit of this process in 1g/dl.
Maximum detectable limit of this process is 7g/dl.
In case of Hemolysis, increased by more than 13% of Albumin value estimation.
In Case of Jaundice, Bilirubin Value of more then 40mg/dl leads to decrease in
album value estimation.
Analytical Value: 1.0—7.0 g/dl
15. Resources Used:
Resources used:
Textbook of Medical Biochemistry by M.N.CHATTERJEA
Textbook of biochemistry for medical students by Sreekumari and DM Vasudevan
Wikipedia and Internet
16. “LIFE IS AN EQUILIBRIUM STATE
BETWEEN DEGRADATION AND
SYNTHESIS OF PROTEINS.”
Yoshinuri Ohsumi,
Nobal Prize Speech in Physiology and Medicine, 2016.
Editor's Notes
NOTE:
To change the image on this slide, select the picture and delete it. Then click the Pictures icon in the placeholder to insert your own image.