Estimation of total protein in serum
Introduction
Total protein make about 7 % of body weight
Blood proteins includes albumin , globulins , fibrinogen , regulatory proteins and other types
Total protein test measures the total amount of two classes of proteins in blood (albumin and globulin)
Albumin is synthesized by liver using dietary proteins and removed from blood by kidney
All plasma proteins are synthesized in the liver except Ȣ – globulins , there are different types of globulin called alpha , beta and gamma globulins , Ȣ – globulin made by immune system
Amino acids are the building block of proteins , in turn proteins are the building block of cells and body tissues
Principle
Total protein test depend on Biuret method for determination of protein concentration
Biuret reagent is made of NaOH , KOH , and CuSO4 together with Na – K tartarate
It is a blue reagent turns to violet in presence of protein in alkaline medium
Normal range
Total protein : 6.5 – 8 g %
Reagents
CuSO4 : color reagent
NaOH , KOH , Na – K tartarate : alkaline medium (working solution)
Standard protein
Procedure
| Reagent | Test | Standard | Blank |
| Serum | 1 ml | – | – |
| St- protein | – | 1 ml | – |
| Water | – | – | 1 ml |
| Working solution | 2.5 ml | 2.5 ml | 2.5 ml |
| Mix , stand for 5 min , then read at 546 nm |
Serum total protein level increased in
Dehydration
Chronic infection or inflammation as virus C , B
Hemolysis
Serum total protein level decreased in:
Malnutrition or malabsorption
Liver disease
Glomerulonephritis
Notes
Total protein = serum albumin + serum globulin
Serum globulin (g %) = total protein (g %) – serum albumin (g %)
Normal range of globulins: 2.8 – 3.2 g %
Serum globulins level increased in:
Liver disease
Infection
Kidney disease
Serum globulins level decreased in:
Liver dysfunction (α , β globulins)
Ratio of albumin / globulin > 1
It must be greater than 1
Increased in high protein in diet
Deceased in liver dysfunction