Which protein does a urine dipstick screening primarily detect?

Which protein does a urine dipstick screening primarily detect?

• A. Albumin
• B. Globulins
• C. Hemoglobin
• D. Myoglobin

Answer: (A)

The test on the urine dipstick that detects protein is optimized to respond to albumin. The protein-detecting pad works by a protein‑error of pH mechanism, which causes a color change most reliably when albumin is present in urine. Globulins and other proteins don’t produce the same strong signal on this pad, so they’re not the primary proteins detected. Hemoglobin or myoglobin, if present, would more specifically affect the blood-detection pad rather than the protein pad, indicating blood rather than proteinuria. Thus the dipstick’s protein result is best interpreted as a reflection of albuminuria, which is why albumin is the correct answer. Keep in mind, though, that the dipstick isn’t as sensitive to very small amounts of albumin (microalbuminuria); dedicated measurements like the albumin-to-creatinine ratio are used for that purpose.

The test on the urine dipstick that detects protein is optimized to respond to albumin. The protein-detecting pad works by a protein‑error of pH mechanism, which causes a color change most reliably when albumin is present in urine. Globulins and other proteins don’t produce the same strong signal on this pad, so they’re not the primary proteins detected. Hemoglobin or myoglobin, if present, would more specifically affect the blood-detection pad rather than the protein pad, indicating blood rather than proteinuria. Thus the dipstick’s protein result is best interpreted as a reflection of albuminuria, which is why albumin is the correct answer. Keep in mind, though, that the dipstick isn’t as sensitive to very small amounts of albumin (microalbuminuria); dedicated measurements like the albumin-to-creatinine ratio are used for that purpose.