Nitrite in Urine (Urine Nitrite): What Your Result Means
What the urine nitrite pad measures, what a positive or negative result means, why a negative result does not rule out a urinary tract infection, and when to get care.
- Published
- August 10, 2024
- Last updated
- October 28, 2026
- Read time
- 3 min read
- Medically reviewed by
-
Rhonda Collins, FNP-C
A positive urine nitrite result means bacteria that turn nitrate into nitrite are probably present in your urine, which most often points to a urinary tract infection (UTI). A negative result does not rule out a UTI, because some bacteria do not make nitrite [1][2].
What does a urine nitrite test measure?
The urine nitrite test is one pad on the routine urinalysis dipstick. Nitrite is not normally found in urine [3]. It forms when bacteria in the bladder convert nitrate, which is normally in urine, into nitrite. Many gram-negative and some gram-positive bacteria can do this, and a positive pad indicates they are present in significant numbers, more than 10,000 per mL [2].
The test does not detect bacteria directly. It detects a chemical that some bacteria make, which is why it is read alongside the other urinalysis results, especially urine leukocytes (leukocyte esterase) and the microscopic urine white blood cell count [1].
What do positive and negative urine nitrite results mean?
Urine nitrite is reported as negative or positive, and Cleveland Clinic lists negative as the normal finding on a urinalysis [4].
- Negative: the expected result. It does not exclude an infection. Some bacteria, such as Enterococcus, do not produce nitrite, and bacteria need about four hours in the bladder to make enough of it, so frequent urination can also give a negative result [1][5].
- Positive: nitrite-producing bacteria are probably present. The test is specific but not highly sensitive: a positive result is helpful, while a negative result does not rule out a UTI [2].
For how nitrite combines with leukocytes, white blood cells, and bacteria on the same report, and what a positive nitrite without symptoms can mean, see our full guide to nitrites in urine.
What causes a positive urine nitrite?
The usual cause is a bacterial urinary tract infection [1][5]. If you have UTI symptoms, a urine culture is often done to identify the bacteria and guide treatment [1].
A positive result can also be false. Contamination of the sample, or test strips left exposed to air, can turn the pad positive without an infection. After one week of air exposure, about a third of strips gave false-positive nitrite results in one report [2]. The bladder-analgesic medicine phenazopyridine can also interfere [2][5].
When should I talk with a clinician about urine nitrite?
Talk with your clinician about a positive nitrite result if you have symptoms of a UTI, such as pain or burning when you urinate, a frequent urge to urinate, or cloudy or strong-smelling urine [1][6]. Seek care right away for back or side pain, chills, fever, or vomiting, which can be signs of a kidney infection [6]. Pregnancy is one of the few situations where a urine culture is useful even without symptoms [5], so raise any positive result with your prenatal care team. Our nitrites in urine guide covers these situations in more detail.
Urine nitrite testing with Mito
The Urinalysis, Routine Test includes the urine nitrite pad along with leukocyte esterase, glucose, protein, and ketones. A microscopic exam is added only when protein, leukocyte esterase, blood, or nitrite is positive on the dipstick [7]. Check the product page for current pricing and availability.
Related Urine Nitrite Resources
References
- MedlinePlus: Nitrites in Urine
- Simerville JA, Maxted WC, Pahira JJ. Urinalysis: A Comprehensive Review. Am Fam Physician. 2005
- MedlinePlus Medical Encyclopedia: Urinalysis
- Cleveland Clinic: Urinalysis
- Hitzeman N, Greer D, Carpio E. Office-Based Urinalysis: A Comprehensive Review. Am Fam Physician. 2022
- MedlinePlus Medical Encyclopedia: Urinary tract infection, adults
- Labcorp: Urinalysis, Routine With Microscopic Examination on Positives (003038)
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