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Pyelonephritis - acute - Management
Dipstick testing
Urinary nitrite and leucocyte esterase
- People with acute pyelonephritis have increased numbers of white blood cells and bacteria in their urine.
- Nitrite is produced by most urinary pathogens in contact with urine. A positive nitrite test is strongly suggestive of a urinary tract infection (UTI). A negative result occurs when:
- No pathogens are present.
- Pathogens are present, but were not in contact with urine long enough to produce detectable levels of nitrite.
- Pathogens that do not produce nitrite are present.
- Leucocyte esterase is present in white blood cells.
- A positive leucocyte esterase test occurs when sufficiently high levels of white blood cells are present in urine, as a response to either infection or contamination.
- A negative leucocyte esterase test occurs either because there is no infection present or because infection is present but the numbers of white blood cells are insufficient to produce a positive result.
Interpretation of urine dipstick tests in people with urinary tract symptoms
- Nitrite positive, and leucocyte esterase positive or negative — over 90% will have a UTI.
- Nitrite negative and leucocyte positive — 50% will have a UTI.
- Nitrite negative and leucocyte negative — 5% will have a UTI.
[Ramakrishnan and Scheid, 2005; COMPASS, 2007]
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