Which statement about nitrite in urine after collection is supported by the material?

• A. Nitrite is immediately altered by bacteria present at collection.
• B. Nitrite cannot be detected in fresh urine.
• C. Bacteria introduced at collection will have no immediate effect on nitrite levels.
• D. Nitrite testing is not part of routine urinalysis.

Answer: (C)

Nitrite in urine comes from bacteria that reduce nitrates to nitrites, and this metabolic step takes time. Because of that delay, bacteria introduced at the moment of collection won’t cause an immediate change in nitrite levels—the nitrite result may stay the same right after collection and only change as bacteria have time to act. This is why the statement about no immediate effect is the best-supported. Nitrite testing is actually a routine part of urinalysis, so saying it isn’t performed in routine UA isn’t correct.