If the blood pad on a reagent strip appears speckled, which of the following may be true?

• A. There are around 5-10 red blood cells/ hpf present.
• B. Myoglobin may be present.
• C. Vitamin C is causing a falsely increased result.
• D. White blood cells are interfering with the reaction

Answer: (A)

When the blood pad on a urine dipstick shows a speckled pattern, it usually means there are intact red blood cells present in the urine rather than a uniform color change from free heme. The peroxidase-like reaction on the pad detects hemoglobin or myoglobin, but the visual speckling specifically reflects discrete red cells that have deposited on the pad during testing. This pattern aligns with a small number of RBCs in the urine, roughly in the range of 5–10 RBCs per high-power field.

If the result were due to free hemoglobin or myoglobin without intact RBCs, you’d expect a more uniform color development rather than speckles. Vitamin C can interfere with the blood test by causing a false negative (not a false positive), so it wouldn’t explain a speckled appearance. White blood cells don’t typically affect the blood pad reaction, so they’re not a likely cause of this pattern.