The reagent test strips used for the detection of protein in urine are most reactive to

• A. Albumin
• B. Hemoglobin
• C. Alpha-globulins
• D. Beta-globulins

Answer: (A)

The main idea is that the urine protein dipstick is designed to be most sensitive to albumin. The strip’s protein-detecting pad contains a dye that changes color when albumin binds in an alkaline environment. Albumin has a strong affinity for this dye, so even small amounts of albumin in urine produce a visible color change. Other proteins, like hemoglobin or various globulins, don’t interact with the dye as effectively in the same way, so they produce little or no color change at comparable concentrations. That’s why the strip is most reactive to albumin—the protein it’s optimized to detect because it’s the most clinically significant urinary protein in early kidney disease.