Nitrite-Positive Urine

Healthy urine contains nitrates. Bacteria in the urinary tract turn nitrates into nitrites, creating nitrite-positive urine. Nitrites in urine (nitrituria) only occur when you have a urinary tract infection (UTI). A urinalysis detects nitrites in urine. Antibiotics kill the bacteria that cause UTIs, getting rid of the nitrites in urine.


What is nitrite-positive urine?

Nitrite-positive urine (pee) is a sign of a possible urinary tract infection (UTI). Healthy urine contains nitrates, a type of nitrogen chemical. When bacteria enter your urinary tract, the bacteria turn these nitrates into a different nitrogen chemical called nitrites. The medical term for nitrites in urine is nitrituria (NI-tri-tur-EE-ah).

Healthy pee shouldn’t have bacteria or nitrites. When bacteria and nitrites are present, it means you may have a UTI. A urinalysis (urine test) can detect nitrites in urine.


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Possible Causes

What causes positive nitrites in urine?

Bacteria in your urinary system cause nitrites to form in your pee. The bacteria enter your body through your urethra (the tube that carries urine out of your body). As a result, you develop a urinary tract infection (UTI).

The bacteria may travel to your bladder (the organ that holds urine), causing bladder inflammation (cystitis). From the bladder, a UTI can spread to your kidneys, the organs that make urine. This leads to a kidney infection (pyelonephritis).

Who gets nitrites in urine?

Women and people assigned female at birth (AFAB) are more prone to getting nitrites in their pee. In fact, people AFAB are 30 times more likely than people AMAB to get UTIs. That’s because their shorter urethras make it easier for bacteria to enter the urethra and reach the bladder. Also, a person AFAB’s urethral opening is closer to the anus, where stool comes out. Exposure to poop containing E. coli bacteria is a common cause of UTIs.


What are the symptoms of a urinary tract infection?

When nitrites in urine cause a UTI, you may experience these symptoms:

Care and Treatment

How do providers test for nitrite-positive urine?

Your healthcare provider orders a urinalysis to test for bacteria and nitrites in urine. You pee into a sample collection cup. This urine test may take place at your provider’s office, hospital or lab. You should get immediate results.

Your provider inserts a special test strip called a urine dipstick into the sample to test for nitrite-positive pee. There are different dipsticks to test for various substances in pee. A nitrite-specific dipstick contains certain chemicals that cause the dipstick to change color when there are nitrites in urine.


What are the downsides of testing for nitrite-positive urine?

Urine dipstick tests for nitrites aren’t always reliable. While a positive test result is often an indication of a UTI, a negative result isn’t 100% reliable. This may be because not all infection-causing bacteria change nitrates into nitrites or produce nitrite enzymes. You can still have a UTI even if the urine dipstick test doesn’t detect nitrites in your pee. Your provider will perform other dipstick tests and check for high white blood cell counts, which may indicate infection.

A false-positive nitrite result (one that says nitrites are present when they’re not) is less common. This result may occur if:

  • The urine dipstick was exposed to air for too long.
  • You use certain over-the-counter (OTC) medicines for urinary pain (phenazopyridine).

Why do healthcare providers test for nitrites in urine?

Healthcare providers often perform urine tests as part of routine physical exams. You may also get a urinalysis if you have UTI symptoms.

Other reasons for nitrite urine tests include:

How is nitrite-positive urine treated?

Your healthcare provider will likely recommend a urine culture to identify the type of bacteria that’s present in your urine. They may prescribe antibiotics to treat the UTI. Antibiotics kill the bacteria causing the infection. Without bacteria, nitrites can’t form.

Some bacteria develop antibiotic resistance. They’re able to fend off the medication that should kill them. If you get frequent UTIs that are difficult to treat, your provider may order a urine culture before prescribing antibiotics. This urine test identifies the specific bacteria causing the infection, enabling your provider to select the most effective medication.

You may start to feel better after just a few days of antibiotics. It’s important to take all the prescribed medication to clear up the infection completely. Stopping an antibiotic too soon can allow the infection to return and contribute to antibiotic resistance.

Can you prevent nitrite-positive urine?

You can take these steps to lower the risk of exposing your urinary tract to nitrite-causing bacteria:

  • Wipe from front to back with toilet paper after peeing and pooping.
  • Avoid feminine deodorants and douches.
  • Pee every three to four hours, and before and after sex.
  • Stay well hydrated.
  • Switch from a vaginal form of birth control (diaphragm or spermicide) to a nonvaginal method.
  • Wear cotton underwear and avoid tight-fitting clothing.

When to Call the Doctor

When should I call the doctor?

You should call your healthcare provider if you experience:

  • Fever.
  • Unexplained abdominal or back pain.
  • Urinary changes, especially foul-smelling or bloody pee.

What questions should I ask my doctor?

You may want to ask your healthcare provider:

  • What is causing the nitrite-positive urine?
  • How can I prevent UTIs?
  • Do I need a urine culture test?
  • Should I look out for signs of complications?

A note from Cleveland Clinic

If you have nitrite-positive urine, it may mean you have a urinary tract infection (UTI). Nitrites only exist in urine when you have an infection. Your healthcare provider will conduct a urinalysis and urine dipstick test to check for nitrites in urine. A nitrite urine test isn’t always accurate, so your provider will check for other signs of a UTI. You’ll need antibiotics to get rid of the UTI. When the antibiotics kill the bacteria, you won’t have nitrites in your urine anymore.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 11/01/2022.

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