Final answer:
The confirmatory test for proteinuria is the immunoelectrophoresis test. Another test that can detect proteinuria is the sulpho salicylic acid test.
Step-by-step explanation:
The confirmatory test for proteinuria is often the immunoelectrophoresis test. This test compares the relative abundance of different types of serum proteins to identify abnormal immunoglobulin proteins in urine samples. Another test that can detect proteinuria is the sulpho salicylic acid test, which is used to detect the presence of proteins in urine.