Can you have a UTI with negative nitrites?

Yes. In a 2004 meta-analysis, the nitrite pad caught only about half of confirmed urinary tract infections. Infections caused by bacteria that make no nitrite, urine that spent less than about 4 hours in the bladder, dilute urine and high-dose vitamin C can all produce a negative nitrite while an infection is present. If burning or urgency continues, a clinician may send a urine culture.

Which bacteria do not produce nitrite in urine?

Enterococcus and Staphylococcus saprophyticus make little or no nitrite, so the nitrite pad often misses infections caused by them. E. coli and related Gram-negative bacteria, which cause most bladder infections, do make nitrite.

Does vitamin C affect a urine nitrite test?

High levels of vitamin C in urine can cause a false-negative nitrite result, and the same is true of the blood pad. Vitamin C reacts with the pad's chemicals first and stops it turning pink. If you take vitamin C supplements, tell the clinician reading your urinalysis.

Should a positive nitrite without symptoms be treated?

Guidelines generally say no for most adults. IDSA 2019 recommends against treating asymptomatic bacteriuria in most adults, including older adults and people with diabetes. Pregnancy and planned urologic procedures that cut through the lining of the urinary tract are the exceptions. Whether this applies to you is a decision for your clinician.

Urine Nitrite: what it measures and how to read it

The distinctions

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Positive nitrite is strong evidence, negative nitrite is weak evidence
Only certain bacteria make nitrite, and they need about 4 hours in the bladder to make enough to detect. A pink pad is a fairly specific sign of bacteria, with specificity above about 90% in most studies. A negative pad misses roughly half of real infections, so symptoms and a culture count for more than a negative nitrite.

A positive nitrite on a urine dipstick means the sample probably contains bacteria that convert nitrate to nitrite, most often E. coli. A negative nitrite means much less. In a meta-analysis (a study that pools the results of many earlier studies) of dipstick accuracy, the nitrite pad caught only about half of confirmed infections, though it rarely flagged people who had none ². If you have a negative nitrite and it still burns when you pee, a urinary tract infection (UTI) is still possible.

What the nitrite pad detects

Most of the nitrate in your body comes from food, mainly vegetables. Your kidneys filter nitrate into urine. Some bacteria carry an enzyme called nitrate reductase, which converts nitrate into nitrite, and the dipstick pad turns pink when it touches nitrite ¹. Normal urine contains no detectable nitrite, so a pink pad means bacteria have been at work on the urine ¹. The bacteria that do this best are Gram-negative species (a large group named for how they stain under the microscope), and E. coli, the most common cause of bladder infections, is one of them.

How a nitrite result forms in the bladder

Nitrate arrives in urine

Nitrate from food, mostly vegetables, is filtered by the kidneys into urine. If you eat little nitrate, there is less for the bacteria to convert.

The right bacteria are present

Bacteria with nitrate reductase, mainly E. coli and related Gram-negative species, convert nitrate to nitrite. Enterococcus and Staphylococcus saprophyticus make little or no nitrite ¹.

Urine sits in the bladder for about 4 hours

The bacteria need roughly 4 hours of bladder time to make enough nitrite to detect ¹. Urgency and frequent urination, two classic UTI symptoms, cut that time short. This step is a common cause of false negatives ¹.

The pad turns pink

Nitrite in the sample reacts with chemicals on the pad and turns it pink. Any pink counts as positive, and a darker pink does not mean more bacteria ¹.

Each step has to happen for the pad to turn positive. If any one of them fails, the result reads negative even when an infection is present. Mechanism per Simerville et al., Am Fam Physician 2005.

Reading your result

The nitrite test has two results, negative or positive. It has no borderline zone and no target number. What a nitrite result means depends on the other pads, the microscopy section and how you feel. The urinalysis guide explains how the whole report fits together.

Dipstick result	What the lab reports	What it suggests	Usual next step
Negative	"Negative"	No nitrite-forming bacteria were detected. A negative result does not exclude infection, because about half of infections test nitrite-negative ².	Read it alongside your symptoms and the leukocyte esterase pad. If symptoms continue, ask about a culture.
Positive	"Positive" (any pink counts; a darker color does not mean more bacteria)	Nitrite-forming bacteria are likely in the sample. A positive is rarely wrong: in most studies, more than 9 in 10 people without infection test negative ².	A clinician's read. With symptoms, often a culture. Without symptoms, usually no treatment, except in pregnancy and before some procedures (see below).

Why a negative nitrite rules out so little

Two numbers describe the accuracy of the nitrite pad. Sensitivity is the share of real infections the test catches. Specificity is the share of people without infection whom the test correctly calls negative. The nitrite pad scores high on specificity and low on sensitivity, so a positive result carries more weight than a negative one ².

About 50%Typical sensitivity of the nitrite pad for UTISpecificity is above about 90% in most studies, so a positive nitrite is more informative than a negative one (Deville et al., BMC Urol 2004) ².

Most false negatives come from the chain in the pathway above breaking at one step. Most false positives come from how the sample was handled. The table lists the common causes in both directions.

Cause	Effect on nitrite	Why it happens
Bacteria without nitrate reductase (Enterococcus, Staphylococcus saprophyticus)	False negative	These bacteria make little or no nitrite ¹
Urine held in the bladder for less than about 4 hours (frequent urination, urgency)	False negative	The bacteria have too little time to convert nitrate ¹
Dilute urine from drinking a lot (shows as low specific gravity)	False negative	Nitrite is diluted below what the pad can detect ¹
A diet low in vegetables	False negative	There is little nitrate for the bacteria to convert ¹
High urinary vitamin C	False negative	Vitamin C reacts with the pad's chemicals first and stops it turning pink ¹
Sample left standing at room temperature before testing	False positive	Bacteria keep growing in the cup and make nitrite after collection ⁶
Phenazopyridine (an over-the-counter urinary pain reliever that turns urine orange; see urine color)	False positive or unreadable	The dye colors the pad ¹

Nitrite, leukocyte esterase and culture compared

The nitrite pad sits next to the leukocyte esterase pad, which detects an enzyme released by white cells. Clinicians read the two pads together, and the leukocyte esterase page has the full table of pad combinations. The short version: when both pads are negative in a well-collected sample, a bacterial UTI is much less likely. If either pad is positive, the next step is a culture or a clinician's read ².

	Nitrite pad	Leukocyte esterase pad	Urine culture
What it measures	Nitrite made by bacteria from nitrate	An enzyme from white cells, a sign of inflammation	Bacteria grown in the lab, then named and counted
What a positive means	Nitrite-forming bacteria, mostly Gram-negative, are likely present	White cells are present; the cause is not yet known	A specific organism, and which antibiotics work against it
Main blind spot	Bacteria that make no nitrite, and short bladder time	Contamination, and inflammation that is not caused by infection	Results usually take a day or more; a contaminated sample can grow skin bacteria
Where it helps most	A fast, specific sign of bacteria	Paired with nitrite, ruling infection out when both pads are negative ²	Symptoms, pregnancy, repeat infections, or when the dipstick and symptoms disagree

The microscopy section of the report adds two counts. A white cell count (counted per high-power field, one view through the microscope) confirms what the leukocyte esterase pad suggests, and a bacteria result shows whether organisms were seen directly. Many squamous epithelial cells point to skin contamination, which makes every pad harder to trust.

Positive nitrite but no symptoms

Bacteria in urine without urinary symptoms is called asymptomatic bacteriuria. It is common, especially in older adults, and it often clears on its own or causes no harm ³. The Infectious Diseases Society of America (IDSA) recommends against screening for or treating asymptomatic bacteriuria in most adults, including older adults, people with diabetes, and people with spinal cord injuries or urinary catheters ³. The American Geriatrics Society gives the same advice for older adults: no antibiotics for bacteriuria unless specific urinary symptoms are present ⁵. The IDSA guideline lists two exceptions: pregnancy, and before urologic procedures that cut through the lining of the urinary tract ³.

The USPSTF recommends screening for asymptomatic bacteriuria using urine culture in pregnant persons.US Preventive Services Task Force, JAMA 2019 (grade B) ⁴

Grade B means the task force found a clear net benefit. The US Preventive Services Task Force (USPSTF) recommends against screening nonpregnant adults (grade D, meaning screening offers no net benefit or its harms outweigh the benefits) ⁴. In pregnancy, untreated bacteria in urine can travel up to the kidneys ⁴, which is why the screening there uses a culture and does not rely on the nitrite pad.

How the test is done

The nitrite test is one pad on a standard urine dipstick, read as part of a routine urinalysis. It is rarely ordered on its own, and you do not need to fast.
A clean-catch midstream sample is best: clean the area, let the first part of the stream go, then collect the middle part. This reduces contamination from skin ⁶.
A first-morning sample is the most sensitive, because that urine has usually sat in the bladder for more than 4 hours ¹.
The sample should be tested promptly or refrigerated. Urine left at room temperature can grow bacteria and turn falsely positive ⁶.
A urine dipstick is one of the cheapest lab tests, and insurance usually covers it when a clinician orders it for symptoms. Pharmacy home strips usually combine the nitrite and leukocyte esterase pads. Treat a home result as a reason to call a clinician, and do not use it to decide on treatment.
There is no routine retest schedule. Nonpregnant adults without symptoms are not screened ⁴. In pregnancy, screening is done by culture, usually early in prenatal care ⁴.

Questions to bring to your clinician

My nitrite was negative, but I have symptoms. Should a culture be sent?
My nitrite was positive, but I feel fine. Is this asymptomatic bacteriuria, and does anything about my situation (pregnancy, an upcoming procedure) change the plan?
Did the sample show many epithelial cells, and should it be recollected?
I take vitamin C supplements or drink a lot of fluid. Could that have affected the result?
My infections keep coming back. Should the culture check for organisms that make no nitrite, such as Enterococcus?

For the other dipstick and microscopy results on the same report, see the urine topic hub. For how urinary infections fit with other infection markers, see the infections topic.

Link · American Family Physician, 2005Urinalysis: a comprehensive reviewA clinician-facing walkthrough of each dipstick pad, including the nitrite chemistry, the 4-hour dwell time and common interferences.aafp.org

Your results, in contextAdd the lab results you already have, and LifeFrom reads each marker next to the others it moves with, in plain language, with the sources it used.Get started

Citations

Simerville JA, Maxted WC, Pahira JJ. Urinalysis: a comprehensive review. Am Fam Physician. 2005;71(6):1153-1162.
Deville WL, Yzermans JC, van Duijn NP, et al. The urine dipstick test useful to rule out infections. A meta-analysis of the accuracy. BMC Urol. 2004;4:4.
Nicolle LE, Gupta K, Bradley SF, et al. Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2019;68(10):e83-e110.
US Preventive Services Task Force. Screening for Asymptomatic Bacteriuria in Adults: Recommendation Statement. JAMA. 2019;322(12):1188-1194.
American Geriatrics Society. Choosing Wisely (2015): Don't use antimicrobials to treat bacteriuria in older adults unless specific urinary tract symptoms are present.
Kouri T, Fogazzi G, Gant V, et al. European Urinalysis Guidelines. European Confederation of Laboratory Medicine. Scand J Clin Lab Invest Suppl. 2000;231:1-86.

Educational context only, not medical advice or a diagnosis. Always discuss your results with a clinician.