Which urinalysis reagent strip test will never be reported out as negative?

Which urinalysis reagent strip test will never be reported out as negative?

• A. Protein
• B. Urobilinogen
• C. Bilirubin
• D. Nitrite

Answer: (B)

The strongest idea here is that urobilinogen is normally present in urine. It comes from the breakdown of conjugated bilirubin in the gut: intestinal bacteria convert bilirubin to urobilinogen, some of which is reabsorbed and then filtered by the kidneys and excreted in urine. Because this process happens under typical conditions, a small amount of urobilinogen is usually detectable in urine, so the strip is very likely to yield at least a trace reading rather than a negative result. In contrast, bilirubin in urine is not expected unless there is conjugated bilirubin spilling into the urine (as in certain liver or biliary disorders), nitrite depends on particular bacteria reducing nitrate (and can be absent in many infections), and protein is not present in normal urine unless there’s kidney or urinary tract pathology. Therefore, urobilinogen is the test most consistently positive on routine urinalysis, making it the best choice for “never negative” in typical samples.

The strongest idea here is that urobilinogen is normally present in urine. It comes from the breakdown of conjugated bilirubin in the gut: intestinal bacteria convert bilirubin to urobilinogen, some of which is reabsorbed and then filtered by the kidneys and excreted in urine. Because this process happens under typical conditions, a small amount of urobilinogen is usually detectable in urine, so the strip is very likely to yield at least a trace reading rather than a negative result.

In contrast, bilirubin in urine is not expected unless there is conjugated bilirubin spilling into the urine (as in certain liver or biliary disorders), nitrite depends on particular bacteria reducing nitrate (and can be absent in many infections), and protein is not present in normal urine unless there’s kidney or urinary tract pathology. Therefore, urobilinogen is the test most consistently positive on routine urinalysis, making it the best choice for “never negative” in typical samples.