I am not at all sure what you are getting at........so I will make a guess.....which may well be way off.
You have been to your GP and a blood test has found an abnormality in your plasma proteins.
There may be many causes for this but a recent infection may well be a reason.
If there are gross abnormalities in any of the plasma proteins, then you will be referred to a Haematologist who will take a sample of your bone marrow.
That is just my guess with the information that you have provided.