Leukocyte esterase-nitrite and bioluminescence assays as urine screens.
The 1-min leukocyte esterase (LE)-nitrite test (Chemstrip 9; Biodynamics, Division of Boehringer Mannheim Biochemicals, Indianapolis, Ind.) and a bioluminescence assay (Monolight centrifugation method; Analytical Luminescence Laboratory, Inc., San Diego, Calif.) were tested for their efficacy as urine screens among 453 patients at a tertiary-care teaching hospital. Both methods had the capacity to exclude significant bacteriuria (greater than or equal to 10(5) CFU/ml) when compared with the results of conventional culture methods, with predictive values of 99 and 93%, respectively, for a negative test. Bioluminescence was the more accurate nonculture method used. Sensitivity and specificity values were 97 and 71%, respectively, for bioluminescence, 82 and 60%, respectively, for LE with nitrite, and 72 and 64%, respectively, for LE without nitrite. At reduced levels of bacteriuria less than 10(5) CFU/ml), the sensitivities of LE-nitrite and bioluminescence were decreased but comparable. The addition of protein and blood test results in the Chemstrip 9, along with LE-nitrite as bacteriuria indicators, were unsatisfactory because of the large numbers of false-positive results attributed to protein and blood determinations. LE activity as detected by the LE test was a poor predictor of significant bacteriuria in both male and female patients. The sensitivity (71%) and specificity (57%) of the LE test in male patients were significantly lower than those previously reported and varied with the patient population studied.
D001437:Bacteriuria / Q000175:diagnosis* / Q000382:microbiology; D004926:Escherichia coli / Q000302:isolation & purification; D004950:Esterases / Q000097:blood*; D005069:Evaluation Studies as Topic; D005260:Female; D006094:Gram-Positive Bacteria / Q000302:isolation & purification; D006801:Humans; D007711:Klebsiella pneumoniae / Q000302:isolation & purification; D007962:Leukocytes / Q000201:enzymology*; D008163:Luminescent Measurements; D008297:Male; D009573:Nitrites / Q000032:analysis*; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification; D011934:Reagent Strips
D009573:Nitrites; D011934:Reagent Strips; D004950:Esterases