The presence of nitrites in urine most commonly means there's a bacterial infection in your urinary tract. This is usually called a urinary tract infection (UTI). A UTI can happen anywhere in your urinary tract, including your bladder, ureters, kidneys, and urethra.

What bacteria cause nitrites in urine?

The presence of nitrite may indicate the presence of E. coli or K. pneumonia; these bacteria produce nitrate reductase, which converts nitrate to nitrite.

What does a positive nitrite test indicate?

A positive nitrite test indicates that the cause of the UTI is a gram negative organism, most commonly Escherichia coli. The reason for nitrites' existence in the presence of a UTI is due to a bacterial conversion of endogenous nitrates to nitrites. This may be a sign of infection.