The test detects bacteria that convert nitrates to nitrites in urine is the:

• A. Urine culture
• B. Urine calcium
• C. Urine protein
• D. Urine dipstick nitrite test

Answer: (D)

This item is about using a urine test to quickly signal a bacterial urinary tract infection by detecting bacteria that convert nitrates to nitrites. Many common urinary pathogens, such as E. coli, have nitrate reductase and reduce nitrates present in urine to nitrites. The dipstick nitrite test uses a chemical reaction that turns a color if nitrite is present, providing a rapid bedside clue that bacteria are in the urine.

It’s a useful screening tool because a positive nitrite result strongly suggests bacteriuria caused by nitrate-reducing organisms. However, not all bacteria reduce nitrate, and nitrites require the urine to be in the bladder for several hours, so a negative result doesn’t completely rule out infection—some infections may be due to organisms that don’t form nitrites or may be too early in onset to produce nitrite yet.

Urine culture, while definitive for confirming infection and guiding antibiotic choices, is more time-consuming and not the nitrite-detecting test. Urine calcium or urine protein measures assess other kidney or systemic issues and do not indicate nitrate-to-nitrite bacterial activity.