Urine Analysis Biomarker
Collection Type: Urine
Related System: Urine Analysis
Nitrite in a urine analysis detects nitrite produced when certain bacteria (typically gram-negative enteric organisms such as E. coli) reduce dietary nitrate in the bladder. The test measures whether nitrite is present in a urine specimen and is used as a rapid screen for bacterial urinary tract infection (UTI). A positive nitrite suggests bacteriuria from nitrate‑reducing organisms; common indications for testing are dysuria, urinary frequency/urgency, suprapubic pain, fever, or unexplained malaise. Results vary by age and sex—women, sexually active individuals, pregnant patients, young children, and older adults have higher UTI rates—while infants and the elderly may show atypical symptoms or asymptomatic bacteriuria that affects interpretation.
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Symptom Checker0 mg/dL OR 0 μmol/L (Negative Not detected)
Q: Is NO2 a nitrite or nitrate?
A: NO2 is neither a nitrite nor a nitrate. NO2 is nitrogen dioxide, a neutral molecular species (a radical) with nitrogen in the +4 oxidation state and is commonly encountered as an air pollutant. Nitrite is the anion NO2− (nitrogen +3), and nitrate is the anion NO3− (nitrogen +5). NO2 therefore differs chemically and ionically from both.
Q: What is positive nitrite in urine?
A: Positive nitrite in urine indicates bacteria that convert nitrate to nitrite—commonly Gram-negative organisms such as E. coli—suggesting a urinary tract infection. A nitrite-positive dipstick is a strong indicator but not definitive; follow-up urine culture and clinical assessment are recommended. False negatives can occur with low bacterial counts, non–nitrate-reducing organisms, or recent antibiotics; false positives are uncommon.
Q: What are nitrites used for?
A: Nitrites are used as food preservatives and curing agents in processed meats to inhibit bacterial growth—especially Clostridium botulinum—while preserving pink color and flavor. Medically, nitrites (e.g., amyl and sodium nitrite) act as vasodilators and are used in cyanide poisoning treatment and historically for angina. They’re also used industrially in chemical synthesis and as corrosion inhibitors; improper use can form nitrosamines.
Q: Is nitrite harmful to humans?
A: Low levels of nitrite in food and drinking water are generally considered safe, but higher exposure can be harmful. Nitrite can form nitrosamines (potential carcinogens) during cooking and can cause methemoglobinemia—especially in infants—by impairing oxygen transport. Regulatory limits exist; reducing processed-meat intake and avoiding contaminated water lowers risk. Consult health authorities if exposure is suspected.
Q: Are nitrites bad for fish?
A: Nitrites are harmful to fish. Even low nitrite levels cause methemoglobinemia (“brown blood disease”), impairing oxygen transport and causing gasping, lethargy, brown gills, and death. Nitrites arise from incomplete nitrogen cycling (overfeeding, poor filtration, overcrowding). Prevent and treat by immediate large water changes, improving biological filtration and cycling, using salt to reduce nitrite uptake, and using nitrite-neutralizing products; aim for 0 ppm.
Q: Is NO2 a pollutant?
A: Yes. Nitrogen dioxide (NO2) is a harmful air pollutant formed mainly by burning fossil fuels (vehicles, power plants, industry). Short-term exposure irritates airways, worsens asthma and respiratory infections; long-term exposure raises risk of chronic lung and cardiovascular disease. NO2 also contributes to ground-level ozone and particulate pollution, so many countries set limits and monitor it to protect public health.