A preliminary evaluation of the interaction between urine specific gravity and leukocyte esterase results using Bayer Multistix and the Clinitek 500.
OBJECTIVE
To determine the sensitivity of the leukocyte esterase (LE) pad to predict microscopically quantified white blood cells in urine sediment and to assess the interaction of urine specific gravity (SG) on leukocyte esterase sensitivity.


METHODS
Microscopic quantification of white blood cells in urine sediment was performed manually and automated chemical urinalysis was performed using the Bayer Clinitek 500 and Multistix 8 SG strips on 422 random urine specimens.


RESULTS
The sensitivity of the leukocyte esterase pad to predict white blood cells in centrifuged urine was 58% (61/106). There was a weak but statistically significant negative correlation between SG and LE pad performance, r = -0.12, p < 0.05.


CONCLUSIONS
The 58% sensitivity of the Multistix leukocyte esterase detection of white blood cells in urine sediment was consistent with previous reports. The negative correlation of specific gravity and leukocyte esterase provides partial explanation for the lack of sensitivity of the leukocyte esterase test.
Lyon
Martha E
ME
Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada. martha.lyon@cls.ab.ca
Ball
Cindy L
CL
Lyon
Andrew W
AW
Walpole
Eleanor
E
Church
Deirdre L
DL
D000293:Adolescent; D000328:Adult; D000368:Aged; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D002498:Centrifugation; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D007962:Leukocytes / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D011934:Reagent Strips / Q000592:standards*; D012680:Sensitivity and Specificity; D013046:Specific Gravity; D014556:Urine / Q000737:chemistry*
D011933:Reagent Kits, Diagnostic; D011934:Reagent Strips; C021443:leukocyte esterase; D002265:Carboxylic Ester Hydrolases