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
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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
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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
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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