Which reagent detects white blood cells on a urine dipstick, and what can cause interference?

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Multiple Choice

Which reagent detects white blood cells on a urine dipstick, and what can cause interference?

Leukocyte esterase is the reagent that detects white blood cells in urine. It works because neutrophils release this enzyme, and when leukocyte esterase is present on the dipstick, it catalyzes a reaction that changes the color, indicating pyuria and potential infection. Interference can skew this signal. Bleach or other strong oxidants can cause a color change on the pad even without leukocyte esterase, leading to a false positive. On the other hand, substances like oxalic acid or a very high specific gravity can hinder the enzymatic reaction or affect the urine matrix, producing a false negative despite the presence of WBCs.

Leukocyte esterase is the reagent that detects white blood cells in urine. It works because neutrophils release this enzyme, and when leukocyte esterase is present on the dipstick, it catalyzes a reaction that changes the color, indicating pyuria and potential infection.

Interference can skew this signal. Bleach or other strong oxidants can cause a color change on the pad even without leukocyte esterase, leading to a false positive. On the other hand, substances like oxalic acid or a very high specific gravity can hinder the enzymatic reaction or affect the urine matrix, producing a false negative despite the presence of WBCs.

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