Leukocyte esterase (LE) is an

esterase An esterase is a hydrolase enzyme that splits esters into an acid and an alcohol in a chemical reaction with water called hydrolysis. A wide range of different esterases exist that differ in their substrate specificity, their protein structure ...

(a type of enzyme) produced by leukocytes ( white blood cells). A leukocyte esterase test (LE test) is a

urine test A urine test is any medical test performed on a urine specimen. The analysis of urine is a valuable diagnostic tool because its composition reflects the functioning of many body systems, particularly the kidneys and urinary system, and specimens a ...

for the presence of white blood cells and other abnormalities associated with

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dis ...

. White blood cells in the urine can indicate a

urinary tract infection A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidne ...

(UTI). Positive test results may be clinically significant in the right context. The LE test is also used to screen for

gonorrhea Gonorrhea, colloquially known as the clap, is a sexually transmitted infection (STI) caused by the bacterium ''Neisseria gonorrhoeae''. Infection may involve the genitals, mouth, or rectum. Infected men may experience pain or burning with u ...

and for amniotic fluid infections. The combination of the LE test with the urinary

nitrite test A nitrite test is a chemical test used to determine the presence of nitrite ion in solution. Chemical methods Using iron(II) sulfate A simple nitrite test can be performed by adding 4 M sulfuric acid to the sample until acidic, and then adding 0.1 ...

provides an excellent screen for establishing the presence of a UTI.

Urine test strip A urine test strip or dipstick is a basic diagnostic tool used to determine pathological changes in a patient's urine in standard urinalysis. A standard urine test strip may comprise up to 10 different chemical pads or reagents which react (change ...

s (dipsticks) can screen for both. A urine sample that tests positive for both nitrite and leukocyte esterase should be cultured for pathogenic

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

. "It has been proposed that the reagent strip for leukocyte esterase designed for the testing of urine (Combur test UX) could be a useful tool for diagnosing

spontaneous bacterial peritonitis Spontaneous bacterial peritonitis (SBP) is the development of a bacterial infection in the peritoneum, despite the absence of an obvious source for the infection. It is specifically an infection of the ascitic fluid – an increased volume of pe ...

(SBP)." Braga et al. concluded that the Combur test UX urine screening test is a very sensitive and specific method for diagnosing SBP in the ascitic fluid of cirrhotic patients who have undergone paracentesis."

References

External links

*
Leukocyte esterase urine test
at MedlinePlus {{Urine tests Urine tests