Nitrites in Urine: What They Mean and When to Worry

When your doctor says you have nitrites in your urine, it’s usually a sign of a urinary tract infection (UTI). Nitrites are chemicals produced when certain bacteria in the urinary system convert nitrates (naturally present in urine) into nitrites.

A positive nitrite test doesn’t automatically mean you have a severe infection, but it does indicate that bacteria are likely present and growing in your urinary tract.

This article explains what nitrites in urine mean, how they’re diagnosed, treatment options, and how to prevent recurrent infections.

What Are Nitrites in Urine?

Under normal conditions, urine contains nitrates — compounds formed from dietary sources like leafy greens and certain vegetables.

When bacteria enter the urinary tract, some species (such as E. coli, the most common cause of UTIs) convert these nitrates into nitrites. Detecting nitrites in urine is therefore one of the most reliable indicators of a bacterial urinary tract infection.

To understand more about identifying and managing infections at home, see our UTI Tests: Essential Guide to Understanding and Managing Your Health.

What Causes Nitrites to Appear in Urine

The presence of nitrites almost always points to bacterial activity in the urinary system. Common causes include:

1. Urinary Tract Infections (UTIs):
   
   

• Caused by bacteria entering through the urethra and multiplying in the bladder.

• More common in women due to a shorter urethra.
  
  

2. Kidney Infections (Pyelonephritis):
   
   

• Occur when bacteria spread from the bladder to the kidneys.

• Often accompanied by fever, flank pain, and nausea.
  
  

3. Catheter Use or Urinary Retention:
   
   

• Prolonged use of catheters or incomplete bladder emptying can promote bacterial growth.
  
  

4. Prostate Infections (in men):
   
   

• Inflammation or infection of the prostate can also lead to nitrites in urine.
  
  

Not all bacteria convert nitrates to nitrites, so a negative nitrite result doesn’t completely rule out infection.

Symptoms of Nitrites in Urine

Treatment focuses on eliminating the underlying infection.

1. Antibiotics:

• Most UTIs are treated with oral antibiotics such as nitrofurantoin, trimethoprim-sulfamethoxazole, or amoxicillin-clavulanate

• Severe infections may require intravenous (IV) antibiotics.
  
  

Always finish the full antibiotic course, even if symptoms improve early.

2. Hydration:

Drinking plenty of water helps flush bacteria out of the urinary tract and supports healing.

3. Pain Relief:

Over-the-counter medications like acetaminophen or phenazopyridine (urinary pain relief) can help ease discomfort.

4. Follow-Up Testing:

After treatment, your doctor may repeat a urine test to confirm the infection has cleared.

When Nitrites in Urine Are a Concern

Nitrites in urine can indicate a serious infection, especially if accompanied by:

• High fever.

• Lower back or side pain.

• Nausea or vomiting.

• Fatigue or confusion (particularly in older adults).
  
  

These symptoms may signal a kidney infection or sepsis — both require urgent medical attention.

How to Prevent Nitrites in Urine

Preventing bacterial infections helps keep your urinary tract healthy.

• Stay hydrated: Drink plenty of water daily.

• Urinate regularly: Don’t hold urine for long periods.

• Wipe front to back: Reduces bacteria transfer to the urethra.

• Urinate after sexual activity: Flushes bacteria from the urethra.

• Avoid irritating products: Scented soaps, sprays, and powders can disrupt the natural balance.

• Maintain good hygiene for catheters if used.
  
  

For recurrent UTIs, your doctor may recommend low-dose antibiotics, probiotics, or cranberry supplements.

When to See a Doctor

Seek medical help if you notice:

• Burning pain during urination.

• Cloudy, bloody, or foul-smelling urine.

• Persistent urinary urgency or frequency.

• Fever or chills.
  
  

Early treatment helps prevent complications and kidney damage.

The Bottom Line

Finding nitrites in your urine is a strong sign of bacterial infection in your urinary tract. Most cases are easily treatable with antibiotics and proper hydration.

However, if left untreated, the infection can spread and become serious.

Maintaining good hygiene, drinking plenty of fluids, and seeking prompt treatment at the first sign of symptoms can help keep your urinary system healthy.

Want to check your urinary health from home?
You can take an at-home urine and kidney function test through Ribbon Checkup and get results in days.

Explore urinary health tests 

Related Resources

Want to dive deeper into kidney health? Check out these helpful reads:

• The Complete Guide to At-Home Kidney Function Tests – Stay on top of kidney health with simple home testing.
  

• How Long Do Kidney Stones Last? Must Know – Get clarity on how long kidney stones typically last.
  

• What Can Mimic Kidney Stone Pain? – Learn about other conditions that cause similar pain.

References

References

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2. Hitzeman, N. (2022). Office-based urinalysis: A comprehensive review. American Family Physician, 106(1), 19–26. https://www.aafp.org/pubs/afp/issues/2022/0700/office-based-urinalysis.html 

3. MedlinePlus. (2024, November 5). Nitrites in urine test. U.S. National Library of Medicine. https://medlineplus.gov/lab-tests/nitrites-in-urine/ 

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5. Papava, V., Didbaridze, T., Zaalishvili, Z., Gogokhia, N., & Maziashvili, G. (2020). The role of urinary nitrite in predicting bacterial resistance in urine culture analysis among patients with uncomplicated urinary tract infection. Urology Research and Practice, Article PMCID: PMC9291437. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9291437/   

6. Stewart, J. J., Robinson, J. L., & Chen, J. Z. (2024). Nitrites for urinary tract infection — Time to say goodbye? JAMA Internal Medicine. https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2833227 

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10. Wikipedia. (2025). Urine test strip. https://en.wikipedia.org/wiki/Urine_test_strip