Leukocyte esterase

Leukocyte esterase-positive urine Antibody-coated bacteria (upper UTI)... 

The nitrite test can be used to detect the presence of nitrate-reducing bacteria in the urine (such as E. coli). The leukocyte esterase test is a rapid dipstick test to detect pyuria. 

A 59-year-old woman presents to an urgent care clinic with a 4-day history of frequent and painful urination. She has had fevers, chills, and flank pain for the last 2 days. Her physician advised her to immediately come to the clinic for evaluation. In the clinic she is febrile (38.5°C [101.3°F]) but otherwise stable and states she is not experiencing any nausea or vomiting. Her urine dipstick test is positive for leukocyte esterase. Urinalysis and urine culture are also ordered. Her past medical history is significant for three urinary tract infections in the past year. Each of these episodes was uncomplicated, treated with trimethoprim-sulfamethoxazole, and promptly resolved. She also has osteoporosis for which she takes a daily calcium supplement. The decision is made to treat her with oral antibiotics for a complicated urinary tract infection with close follow-up. Given her history what would be a reasonable empiric antibiotic choice Depending on the antibiotic choice are there potential drug interactions she should be counseled on ... 

The presence of greater than 1-2 erythrocytes or neutrophils per high-power field confirms a positive result of dipstick analysis for blood or leukocyte esterase. Increased number of hyaline casts (small numbers are normal in most species), or the presence of granules (cells or cellular debris) within casts may be indicative of tubular injury. The presence of renal tubular epithelial cells in urine sediment strongly indicates tubular injury (Stonard 1990 Hofmann et al. 1994 Finco 1997 Finn and Porter 1998 Newman and Price 1999). 

LAP is also seen in the urine with very early glomerular disease (Bedir et al. 1996). The assay substrate is also a substrate for leukocyte esterase and thus increased neutrophils in the urine (pyuria) will cause a false positive result (Vlaskow et al. 2000). 

Leukocyte esterase Urine P)rrrole amino ester hydrolysis... 

Chernesky M, Jang D, Krepel J, Sellers J, Mahony J. Impact of reference standard sensitivity on accuracy of rapid antigen detection assays and a leukocyte esterase dipstick for diagnosis of Chlamydia trachomatis infection in first-void urine specimens from men. J Clin Microbiol 1999 37 2777-80. 

Urine leukocyte esterase (Uv) v and nitrite Does this patient have. a urinary tract infection Positive LE, positive nitrite, or both Send urine to laboratory for microscopy, culture and sensitivity and treat if positive Appropriate use of antibiotics, decreased morbidity... 

The presence of leukocyte esterase is indicative of pyuria. The detection of nitrite is indicative of the presence of bacteria that degrade nitrate excreted in the urine. The combination of the two tests is valuable in patients with urinary tract infection. The absence of both constituents is a valuable test to rule out urinary tract infection, thereby reducing the number of samples sent to the laboratory for further tests. The nitrite test may be less helpful in young children in whom the urine remains in the bladder for less time, thereby limiting the time for nitrite production. 

Leukocyte esterase is released from lysed granulocytes in the urine its presence is suggestive of urinary tract infection. If the processing of the urine sample is delayed, a false-positive leukocyte esterase may be reported if the sample is contaminated. 

Importantly, cultures of specimens from purportedly infected sites that are obtained by sampling from or through one of these contaminated areas may contain significant numbers of the normal flora. In the case of urine cultures, the urinalysis should be used in combination with culture results to assess the presence of WBCs, nitrite, and leukocyte esterase to help confirm infection and rule out colonization. 

ACB antibody-coated bacteria EPS expressed prostatic secretions LE leukocyte esterase PAF prostatic antibacterial factor PMN polymorphonuclear leukocyte UTI urinary tract infection WBC white blood cell... 

Lactic acid Leukocyte esterase Nitrites Osmolality blood urine... 

A negative urine leukocyte esterase indicates the antibiotic is effective in treating the infection. Leukocytes and nitrates are used to determine bacteri-uria and other sources of urinary tract infections. 

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