Which test is used as a confirmatory test for protein in urine?

The Sulfosalicylic Acid Precipitate Test is utilized as a confirmatory test for protein in urine because it specifically detects the presence of proteins through precipitation. In this test, the urine sample is mixed with sulfosalicylic acid, and if proteins are present, they will precipitate out of the solution, forming a turbidity or cloudiness. This allows for a clear visual indication of proteinuria.

The test is effective because it can detect both albumin and other proteins, which might not be fully assessed with less specific tests. The sensitivity of this test makes it a reliable method to confirm the presence of protein when routine screening methods such as a reagent strip test indicate a positive result.

In contrast, the Biuret Test is primarily used in laboratory settings to measure total protein concentration but is not commonly applied as a routine test for urinary proteins in clinical practice. The Benedict's Test is designed for detecting reducing sugars, such as glucose, and is not related to protein assessment. The Reagent Strip Test provides an initial indication of protein presence, but it acts primarily as a screening tool rather than a definitive confirmatory test. Thus, the Sulfosalicylic Acid Precipitate Test is the most suitable choice for confirming protein in urine