Nitrates and nitrites are both forms of nitrogen. The difference is in their chemical structures — nitrates have three oxygen atoms, while nitrites have two oxygen atoms.

Both nitrates and nitrites are found naturally in certain vegetables, like leafy greens, celery, and cabbage, but are also added to processed foods like bacon, as a preservative.

Having nitrates in urine is normal and not harmful. However, having nitrites in your urine could mean you have an infection.

The presence of nitrites in urine most commonly means there’s a bacterial infection in your urinary tract. This is usually called a urinary tract infection (UTI).

A UTI can happen anywhere in your urinary tract, including your bladder, ureters, kidneys, and urethra.

Harmful bacteria find their way into the urinary tract and reproduce rapidly. Some types of bacteria have an enzyme that converts nitrates into nitrites. This is why the presence of nitrites in your urine is an indicator that you may have a UTI.

UTIs usually have other symptoms, such as:

Some people won’t experience symptoms of a UTI right away. If you’re pregnant, your doctor may want to test your urine for nitrites and other factors at several points during your prenatal care as a precautionary measure, even if you don’t have symptoms of a UTI.

UTIs are common in pregnancy and are dangerous. They can cause high blood pressure and premature delivery if left untreated. UTIs during pregnancy are also more likely to spread to the kidneys.

Nitrites in the urine are diagnosed with a test called a urinalysis. A urinalysis may be done for a variety of reasons including:

  • if you have symptoms of a UTI, like painful urination
  • during a routine checkup
  • if you have blood in your urine or other urinary problems
  • before a surgery
  • during a pregnancy checkup
  • if you’re admitted to a hospital
  • to monitor an existing kidney condition
  • if your doctor suspects you have diabetes

Before a urinalysis, inform your doctor of any medications, vitamins, or supplements you're taking.

Clean catch urine sample

You’ll be asked to provide a “clean catch” urine sample. For this, you’ll have to clean the genital area well before collecting urine to make sure the sample isn’t contaminated with bacteria and cells from the nearby skin.

As you begin to urinate, first allow some of the urine to fall into the toilet. Then collect about two ounces of urine in the cup provided by your doctor. Avoid touching the inside of the container. You can then finish urinating into the toilet.

Analysis of the urine sample

There are several steps to analyze urine in a urinalysis:

  • First, your doctor will visually inspect the urine to look for cloudiness — cloudy, red, or brown-colored urine usually means there’s an infection.
  • Second, a dipstick (a thin stick with strips of chemicals) is used to check for a variety of factors, such as the pH, and the presence of protein, white blood cells, or nitrites. A dipstick test can be done immediately after the sample is taken.
  • If the dipstick test reveals abnormal results, the urine sample may be sent off to a laboratory for further testing and microscopic evaluation.

A positive test for nitrites in the urine is called nitrituria. If you have nitrituria, your doctor will likely want to send your urine sample to a laboratory for a urine culture test. In a urine culture, your doctor can find out which specific type of bacteria are causing your UTI.

A urine culture usually takes about two to three days to be completed, sometimes longer depending on the type of bacteria. On average though, you should expect to see your results in three days.

Keep in mind that not all bacteria are capable of converting nitrate to nitrite. So, you can have a negative nitrite test and still have a UTI. This is why your doctor considers the result of many tests, not just one test, when diagnosing a UTI.

Untreated UTIs become more severe as they spread toward the kidneys. An infection in the upper urinary tract is much more challenging to treat. Eventually, the infection can spread into your blood, causing sepsis. Sepsis can be life-threatening.

Additionally, UTIs in pregnant women can be dangerous for the baby and mother.

The treatment for nitrites in your urine usually involves a course of antibiotics. The exact type your doctor will prescribe depends on what kind of bacteria has infected your urinary tract, your medical history, and whether or not you’re pregnant.

Proper treatment with antibiotics should resolve your symptoms within a day or two. Be sure to follow your doctor’s instructions and take the entire course of antibiotics. Not doing so can cause the infection to come back and your doctor will have to prescribe a different type of antibiotic.

Drinking plenty of water to flush out the bacteria is also an important step in helping you recover more quickly.

Even if you don’t have any other symptoms, nitrites in your urine means you have harmful bacteria growing where they shouldn’t be. It’s very important to treat this infection as early as possible.

When dealt with promptly, UTIs are easily treatable and usually resolve quickly in a couple of days.

If a urinalysis comes back positive for nitrites, see your doctor for further evaluation.

Seek emergency help if you have any of the following symptoms as it could mean the infection has spread to your bladder or kidneys:

If you experience any of the above symptoms, or any other symptoms of a UTI, you should seek a doctor’s care as soon as possible.