Nitrite in urine - what does it mean?

Nitrite in the urine The presence of nitrates( not nitrites) in the urine is relatively normal, especially given the current food( nutritional supplements, accelerated methods of growing plants and animals).But during the health problems in the bladder, bacteria can appear and actively multiply. They excrete a special enzyme and under its action nitrates begin to turn into nitrite , showing up in the urine.

Positive assay for nitrite in urine means the presence of bacteria in the bladder, and hence infections in the urinary system.

Infection can be in the upper part of the urinary system( pyelonephritis) or lower( cystitis, urethritis).In the first case, it is much more difficult to treat and diagnose. Usually, nitrite in urine is detected when other symptoms begin to appear: pain, urination disorder, chills, fever.

The most common bacterium that causes this kind of infection is Escherichia coli( E. coli).It is present in the large intestine, stomach, around the anus, and in the stool. But there may be others.


  • 1 What are nitrites and where do they come from?
  • 2 Why do I need a nitrite test?
  • 3 What if there are nitrites and there are no symptoms?
  • 4 Nitrite in urine in adults
    • 4.1 Are there different nitrite in urine in women and men?
    • 4.2 The most common reasons for the detection of nitrite in the urine of women:
    • 4.3 The most common reasons for the detection of nitrite in the urine of men:
  • 5 Nitrite in the urine of the child
  • 6 Nitrite in the baby
  • 7 Nitrite in the urine during pregnancy
  • 8 Golden rules for the nitrite analysis:

What are nitrites and where do they come from?

Nitrites are formed in the urine from nitrates( both are nitrogen compounds).Nitrates in large quantities are contained in plant products and enter the urinary tract directly from the blood. They are filtered in the kidneys, and then gradually concentrated in the bladder. Responsible for the process of nitrite formation are bacteria. However, the actual "responsibility" to the body for these very nitrites, microbes do not carry. Rather, it is simply a side effect of the presence of bacteria in the urine, their trace. Normally, there should not be nitrites in the urine, because there should not be bacteria. Consequently, the detection of nitrites is an indicator of the rapid growth of microbes in the urinary tract.

Why do I need a nitrite test?

Test for nitrite

An example of test strips that allow you to perform nitrite analysis by other means. But its results are considered very reliable. The price varies, but you can buy them at no cost( approximately from $ 4 for 50 pcs.)

First of all, you need to understand that this is an express test. That is about getting a "yes-no" answer. Or there are bacteria, or they are not. The researcher does not know how many bacteria and what they are, to what antibiotics are sensitive, in which part of the urinary system they multiply. Therefore, no, even a very modern test strip for the detection of nitrites can replace the same "banal" general analysis of urine. Moreover, if the infection is caused by gram-positive bacteria and pseudomonads( and this happens quite often), nitrites are not detected at all, because these two families of microorganisms do not process nitrates. But a lot of troubles are brought to a person( cystitis, caused by gram-positive bacteria, usually goes into a chronic form and is not amenable to treatment).

What if there are nitrites and there are no symptoms?

In this case, we are dealing with asymptomatic bacteriuria or a false positive result of the analysis. When there is no bacteria or any signs of inflammation in a urine sample in which nitrites are detected, the analysis will have to be remade. If both nitrites and bacteria are detected, treatment should be started immediately.

Nitrite in urine in adults

Are there different nitrite in urine in women and men?

Of course not. Both the bacteria and the nitrites produced by these bacteria are exactly the same. Male and female urinary systems differ only in the final section: the urethra in women is short and relatively wide, and in men it is long and narrow. That is why the laboratories are correcting for the different degree of contamination of the material handed down by men and women. Contamination of the sample is of fundamental importance because during storage( e.g., pending transport to the laboratory) bacteria actively proliferate first by absorbing nitrate, and then die from lack of nutrients, making the amount of nitrite is also gradually reduced. The reliability of the result also changes.

Women are more likely to get bacteria into the bladder, since they have a shorter urethra. It is easier for bacteria to penetrate into the bladder. Some of the fair sex can face 3 times a year with a similar problem.

The most common reasons for the detection of nitrite in the urine of women:

  • cystitis;
  • urethritis;
  • pyelonephritis.

The most common causes of nitrite detection in urine in men:

  • prostate adenoma;
  • cystitis;
  • inflammation of the ureter( most often in the course of urolithiasis with attachment of secondary infection);
  • pyelonephritis.

Nitrite in the urine of a child

In order for microorganisms to synthesize as many nitrites as they can already determine a test strip, urine should be in the bladder for 4 hours or more. As a rule, the first morning portion of urine satisfies these conditions. A daily portion can also be taken, only it is important to sustain this time interval between urination.

Thus, in order to be accurately assured of the correctness of the result, it is necessary to pass the concentrated urine. However, in practice this is not always feasible. For example, a child with a slight increase in body temperature is suspected of having acute respiratory viral infection, begin to actively solder, according to the pediatrician's recommendation. Urination becomes more frequent, urine becomes less concentrated, even the same, "the first morning".And when the doctor comes to the idea of ​​a possible urinary tract infection and directs the child to the analysis, the laboratory defines a large number of white blood cells, red blood cells, and even protein in the sample - but nitrite, as well as bacteria, there may be missing. Ideally, of course, in order to avoid a false negative test result for nitrites, fluid intake on the eve of urine delivery should be limited.

Nitrite in infants

urine taken for analysis in infants, should be transported to the laboratory as soon as possible, and here's why:

  1. collection analysis is usually difficult: kids with incomprehension are attempting to tie the bag and cause urination at any capacity. Thus, the likelihood of getting into the urine of bacteria from the skin of the baby and the hands of an adult increases.
  2. Careful urethral hygiene is also difficult.
  3. In boys, the probability of inflammation of the prepuce is great for a year, and this means - additional contamination of urine by bacteria. The probability of a false positive result increases.

In most cases, a bacterial infection in infants is localized in the bladder, and, interestingly, there are cases "mixed infection" - a combination of bacterial growth with active reproduction in the bladder of various herpes viruses.

Nitrite in urine during pregnancy

Positive result on nitrites in pregnant women requires increased attention: first of all obstetricians-gynecologists are afraid of pyelonephritis. Inflammation of kidneys, both acute and chronic, may cause miscarriage, fetal infections, eclampsia, elevated blood pressure( which by itself impairs blood flow to the fetus).


Golden rules for nitrite analysis:

  • if possible, reduce fluid intake on the eve of the analysis;
  • on the eve of the analysis include in the diet carrots, cabbage, leafy vegetables;
  • , exclude for 3 days products containing ascorbic acid and preparations containing vitamin C( this reduces the concentration of nitrites);
  • - the analysis is not performed during antibiotic therapy and 10 days after completion of the course of this therapy;
  • analysis is not performed with fenazopyridine drugs( this is a remedy for pain and burning in inflammatory diseases of the urinary system).