Lab Test: Nitrite (Urine) Level
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- Detection of urine nitrites as a screening test for urinary tract infection (UTI)
- This test helps identify the presence of bacteria that can reduce nitrate to nitrite
- Implies bacteriuria
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Negative
- A negative result is considered normal or less indicative for the presence of bacteria in the urine. However, the sensitivity is not 100% and false negative results can occur.
- Suspected urinary tract infection (UTI)
- Positive dipstick urinalysis for nitrites may indicate the presence of UTI. The most accurate results to screen for asymptomatic UTI are obtained by dipstick testing for combinations of urine nitrite and/or leukocyte esterase.
- For definitive diagnosis, urine culture is the gold standard for diagnosing UTI.
- A negative urine dipstick test for nitrite does not rule out UTI in patients with a high likelihood of having the infection.
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This
test is based on the principle that many (but not all) bacteria produce an
enzyme called reductase, which can reduce urinary nitrates to nitrites.
- Clinical testing is done with a dipstick
containing a reagent that reacts with nitrites to produce a pink color, thus
indirectly suggesting the presence of bacteria.
- A positive test result indicates the need for a urine culture.
- Nitrite screening enhances the sensitivity of the leukocyte esterase test to detect UTIs.
- Semeniuk H et al. J Clin Microbiol 1999;37:3051-2.
- Gallagher EJ et al. Am J Emerg Med 1990;8:121-3.
- LaGow B et al., eds. PDR Lab Advisor. A Comprehensive Point-of-Care Guide for Over 600 Lab Tests. First ed. Montvale, NJ: Thomson PDR; 2007.
- Pagana K, Pagana TJ eds. Mosby's Manual of Diagnostic and Laboratory Tests. 5th Ed. St. Louis, Missouri. 2014.
Description
Reference Range
Indications & Uses
Clinical Application
References
MESH Terms & Keywords
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