Home > Available Issues
Original Articles
The Comparison of Microscopic Urine Sediment, Nitrite, and Leukocyte Esterase Tests for Bacteriuria
Bo-Moon Shin, M.D., Ph.D.
Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University, Seoul, Korea
Vol.36 Num.2 (p92~96)
Background:Although bacteriologic culture remains the gold standard for detecting bactriuria, leukocyte esterase, nitrite and urine microscopy are also widely used. However, it is not uncommon to be presented with a discrepancy between these tests.
Methods:We performed leukocyte esterase and nitrite tests by urine reagent strip testing (Combur 10 Test, Roche, Germany), microscopic urinalysis, and by bacteriologic urine culture on 290 persons.
Results:The number of pathogens and non-pathogens were 51 (17.6%) and 87 (30.0%) respectively. The number of cases in which no microorganism was isolated (NMI group) was 152 (52.4%). The concordance rate between leukocyte esterase and microscopic leukocytes (leukocyturia) was 70.7%. The sensitivities and specificities of leukocyte esterase, microscopic leukocyte and microscopic bacteria were 72.5%/61.8%, 76.5%/44.1 % and 80.4%/92.1% respectively, and their positive predictive values and negative predictive values were 24% (62.3%)/69.1% (89.7%), 21.3% (53.6%)/62.6% (88.8%) and 51.9% (84.8%)/66.4% (95.3%), respectively. Although the nitrite test showed higher positive rates in the pathogen groups (37.2%) than in the non-pathogen group (2.2%) and NMI group (1.3%), this was only marginally significant.
Conclusion:The microscopic estimation of bacteria is more a predictable marker of bacteriuria, rather than leukocyte esterase, nitrite, and microscopic leukocytes, in urine.
Keywords : Leukocyte esterase, Leukocyturia, Nitrite, Bacteriuria