A comparison of dilution adjustment methods for urinary enzymes.
Urinary dilution adjustment methods can be used to reduce the intra-individual variability in concentrations of metals and other substances in urine due to variability in urinary flow. In this study linear and non-linear dilution adjustments with urinary flow, creatinine (CREAT) and urinary density (UD) were compared for the urinary enzymes alanine amino peptidase (AAP), beta-galactosidase (beta GAL) and N-acetyl-beta, D-glucosaminidase (NAG). The most optimal dilution adjustment for AAP was: AAPadjusted = AAPmeasured/(CREATmeasured)0.824 The optimal dilution adjustment for beta GAL was: beta GALadjusted = beta GALmeasured/(CREATmeasured)0.878 For NAG the optimal dilution adjustment parameter was the conventional linear adjustment with SG. It could not be determined whether urinary dilution methods can be useful for population based reference intervals of urinary enzymes. If personal reference intervals can be calculated, urinary dilution adjustment methods may be useful by reduction of intraindividual variability.
Coronel Laboratory for Occupational and Environmental Health, University of Amsterdam, Netherlands.
A J
AJ
Verplanke
R F
RF
Herber
J P
JP
Broersen
D000118:Acetylglucosaminidase / Q000652:urine*; D000328:Adult; D000626:Aminopeptidases / Q000652:urine*; D018826:CD13 Antigens; D003404:Creatinine / Q000652:urine; D006801:Humans; D008297:Male; D011786:Quality Control; D012016:Reference Values; D012044:Regression Analysis; D014556:Urine / Q000502:physiology; D001616:beta-Galactosidase / Q000652:urine*
D003404:Creatinine; D001616:beta-Galactosidase; D000118:Acetylglucosaminidase; D000626:Aminopeptidases; D018826:CD13 Antigens