And in about half of all cases of clear urinary tract infection, no nitrite is found in the urine, as, for example, not all bacterial species form nitrite.
Or the urine wasn’t in the bladder long enough and the bacteria just didn’t have enough time to form nitrite.
So the urine should remain in the bladder for more than four hours to obtain a reliable test result. For this reason, always the morning urine should be examined for a meaningful examination result. If the urine is heavily diluted due to large amounts of drinking, the nitrite test can also be negative, even though there is a urinary tract infection.
If there are extremely many bacteria in the urine, the nitrite can be further broken down by the bacteria and is then no longer detectable. If there is not enough nitrate in the urine from the beginning, any bacteria that may exist cannot form a nitrite.
With one-sided diet, malnutrition, artificial diet or breast milk nutrition of the infant, there may be too little nitrate in the urine, so that the problem of nitrite detection persists. Antibiotics can also interfere with nitrite formation.
All these points show that if there is a suspicion of a urinary tract infection, the test for nitrite in the urine is far from sufficient, but that further examinations are in any case necessary.