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A nitrite test is a standard component of a urinary test strip. A positive test for nitrites in the urine is called nitrituria. This test is commonly used in diagnosing urinary tract infections (UTIs). A positive nitrite test indicates that the cause of the UTI is a Gram-negative organism, most commonly Escherichia coli. The reason for nitrites ...
Urinalysis is the most useful test to start the work up in a patient of dysuria. Urinalysis positive for nitrite carries a high predictive value of a positive urine culture. Also, urine dipstick showing leukocytes as equal predictive value as the presence of nitrites. When both are present, the predictive value goes even higher.
Bacteria, lymphocytes and epithelial cells from the genitourinary tract do not contain esterases. [21] Neutrophil granulocytes are the leukocytes most commonly associated with urinary infections. A positive test for leukocyte esterase normally indicates the presence of bacteria and a positive nitrite test (although it is not always the case).
The presence of nitrites, which causes a pink color on the reagent strip pad, therefore acts as an indicator of urinary tract infection. [51] The nitrite test is quite specific, meaning that someone is likely to have a UTI if it is positive, but it is not sensitive; a negative result does not reliably indicate that the subject does not have a UTI.
Another test, urine microscopy, looks for the presence of red blood cells, white blood cells, or bacteria. Urine culture is deemed positive if it shows a bacterial colony count of greater than or equal to 10 3 colony-forming units per mL of a typical urinary tract organism. Antibiotic sensitivity can also be tested with these cultures, making ...
The nitrite test is commonly used to diagnose urinary tract infections by measuring the concentrations of nitrite in solution, indicating the presence of a gram-negative organism. A simple nitrite test can be performed by adding 4 M sulfuric acid to the sample until acidic, and then adding 0.1 M iron (II) sulfate to the solution.
The Griess test is an analytical chemistry test which detects the presence of nitrite ion in solution. One of its most important uses is the determination of nitrite in drinking water. The Griess diazotization reaction, on which the Griess reagent relies, was first described in 1858 by Peter Griess.
Leukocyte esterase (LE) is an esterase (a type of enzyme) produced by leukocytes (white blood cells). A leukocyte esterase test (LE test) is a urine test for the presence of white blood cells and other abnormalities associated with infection. White blood cells in the urine can indicate a urinary tract infection (UTI). Positive test results may ...