Practical 2: Investigation of Total Protein and Albumin
No description yet. This curated deck is ready for daily study.
Card preview (24)
What sample do we use when measuring proteins?
Serum
What is serum
The fluid that remains after plasma has clotted
Why is it important to note that serum is the fluid that remains after plasma has clotted?
It means fibrinogen and most of the clotting factors have been removed
Why do we measure proteins?
They give us a general insight into a person’s health
What plasma proteins are not synthesised in the liver? (3)
Immunoglobulins Haemoglobin Hormonal proteins
What are the roles of plasma proteins? (8)
Transport Enzyme catalysis Homeostatic control Hormonal regulation Blood coagulation Immunity Growth and repair Heredity
Why would calcium levels be measured (3)
To screen/monitor for bone diseases To screen/monitor for diseases of the parathyroid gland To screen/monitor for diseases of the kidney
What is free/ionised calcium?
Calcium not attached to proteins in the blood
What percentage of calcium in the blood is attached to proteins
About 50%
What is corrected calcium concentration?
An estimate of the total concentration of calcium as if the albumin concentration was normal
Why is a corrected calcium concentration needed? (3)
50% of calcium in the blood is bound to plasma proteins The majority of protein in plasma is albumin A low albumin would give a low calcium concentration however this doesn’t accurately reflect the calcium concentration i.e. it might not actually be low
How does corrected calcium concentration work?
For every 1g/L that the albumin concentration is below the mean, the calcium concentration is 0.02 mmol/L below what it would be if the albumin concentration was normal
What method is used to measure total protein
Biuret
What does a total serum protein test measure (2)
The total amount of protein in the blood The amounts of albumin and globulin in the blood
Why are total serum protein tests carried out?
They are used in the diagnosis and treatment of a variety of diseases involving the liver, kidney and bone marrow as well as other metabolic or nutritional disorders
What is the principle behind the Biuret method of measuring total serum protein (3)
Cupric ions (copper ions) in an alkaline solution react with the peptide bonds of proteins and polypeptides containing at least two peptide bonds This react produces a violet coloured complex The absorbance of this complex at 546nm is directly proportional to the concentration of the protein in the sample
What absorbance is the biuret reagent read at
546nm
What colour is the polypeptide-biuret complex?
Violet
How must a blood sample be collected and prepared for the total serum protein test (4)
Sample = serum, heparinized plasma or EDTA plasma Normal procedures for collecting and storing serum Serum will be stable for 3 days between 2+ and +8 degrees Celsius Serum will be stable for 6 months at -20 degrees Celsius
At what temperature should a total serum protein test be carried out at
Room temperature or 37 degrees
What is your blank for the total serum protein test?
Water
How many standards should you use for the total serum protein test
Three
How many controls should you use for the total serum protein test
2
How much incubation is needed for the total serum protein test
20 minutes before reading absorbance