Red blood cells in urine sediment are usually measured per high-power field. What is the typical normal range?

• A. 0–3 RBCs per high-power field.
• B. 5–10 RBCs per high-power field
• C. 10–20 RBCs per high-power field
• D. 0–1 RBCs per low-power field

Answer: (A)

Counting red blood cells in urine sediment is a semi-quantitative assessment done under high magnification to estimate microscopic hematuria. A normal urine sample typically shows very few RBCs when viewed this way; most laboratories consider 0 to 3 RBCs per high-power field as the reference range. Values in this range can occur in routine samples and may reflect minor contamination or natural variation. Higher counts, such as 5–10 or 10–20 RBCs per high-power field, indicate microscopic hematuria and prompt clinical follow-up. Reporting RBCs per a low-power field isn’t standard practice for this measurement, since counting under low power reduces resolution and accuracy. Therefore, 0–3 RBCs per high-power field best represents the typical normal range.