Dipstick protein testing is primarily sensitive to which of the following in urine?

Dipstick protein testing is primarily sensitive to which of the following in urine?

• A. Albumin
• B. Globulins
• C. Tamm-Horsfall protein
• D. Cystatin C

Answer: (A)

Dipstick protein testing is designed to be most sensitive to albumin. The strip uses a color-changing reaction that relies on albumin binding to the indicator dye (a protein-dye interaction known as the protein error of pH), which occurs at relatively low concentrations. Albumin is the predominant protein that leaks into urine in many forms of clinically significant proteinuria, so this test detects it best. Other urinary proteins, such as globulins, Tamm-Horsfall protein, or cystatin C, either appear in lower amounts or do not provoke the same dye reaction as reliably, so they do not produce as strong or consistent a signal on the dipstick.

Dipstick protein testing is designed to be most sensitive to albumin. The strip uses a color-changing reaction that relies on albumin binding to the indicator dye (a protein-dye interaction known as the protein error of pH), which occurs at relatively low concentrations. Albumin is the predominant protein that leaks into urine in many forms of clinically significant proteinuria, so this test detects it best. Other urinary proteins, such as globulins, Tamm-Horsfall protein, or cystatin C, either appear in lower amounts or do not provoke the same dye reaction as reliably, so they do not produce as strong or consistent a signal on the dipstick.