BNP is a blood test.
in biuret test the presence of peptide bonds gives a violet color. but it should be noted that a minimum of two peptide bonds should be present in the protein to get a positive answer to this test.
the results are negative because pesin breaks peptide bonds. therefore no peptide will be found in the test.
You must have at least two, those that will form the peptide linkage (NH2 and COOH) since Biuret test is for detecting peptide linkages.
No, phenol does not give a positive biuret test. The biuret test is used to detect the presence of proteins, not phenol. Phenol is a type of organic compound that does not contain the peptide bonds that the biuret test reacts with.
you can get tested. a neurologist can test your brainwaves and brain patterns. it is affordable to have this done.
B-type natrurietic peptide. 
The B-type Natriuretic Peptide test, is a blood test which is looking for any type of heart failure. The level of BNP increases when there are symptoms of heart failure.
A sonogram of the brain is often done in the NICU to check for a brain bleed. This test is sometimes a routine part of NICU care.
The biuret test is a chemical test used for detecting the presence of peptide bonds. In a positive test, a copper(II) ion is reduced to copper(I), which forms a complex with the nitrogens and carbons of the peptide bonds in an alkaline solution. A violet color indicates the presence of proteins.It is possible to use the Biuret reaction to determine the concentration of proteins because (for most proteins) peptide bonds occur with approximately the same frequency per gram of material. The intensity of the color, and hence the absorption at 540 nm, is directly proportional to the protein concentration, according to the Beer-Lambert law.
At least two peptide bonds must be present in a molecule to give a positive biuret test. The biuret reagent interacts with peptide bonds in proteins, forming a colored complex that can be detected visually.
I am not aware of "measurements" but some test that are done are CT and MRI of the brain, a swallowing test, and bloodwork. After a time there may be some neurological tests done as well. Hope this is what you are after.
The biuret test can be used to show the hydrolysis of proteins. In this test, a blue to purple color change indicates the presence of peptide bonds being hydrolyzed. This color change occurs due to the formation of a coordination complex between copper ions and the peptide bonds.