What problems might one encounter performing a biuret test for protein on intact red blood cells?

The biuret test refers to a chemical examination done to determine the existence of peptide bonds. In the presence of peptides, a violet color coordination complexes are formed by copper ions in an alkaline solution.  

The intact red blood cells comprise pigment hemoglobin and hemoglobin also exhibits the same color as of biuret test result color. Thus, one of the prime issue, which can take place at the time of biuret test is the hemolysis of the red blood cells that can ultimately affect the result.  

Therefore, one of the solution to overcome the issue is to remove the hemoglobin from the cells prior to performing the analysis.