This study was conducted to evaluate a more reliable adjustment method of urinary delta-aminolevulinic acid (ALA) concentration. Urinary ALA concentration, specific gravity (SG) and creatinine (Cr) concentration were measured in spot urine
samples
of
245 healthy subjects, ages 18 to 68 years, who were not occupationally exposed to lead. Three adjusted values, SG-adjusted ALA concentration, ratio of ALA concentration to Cr concentration (ALA/Cr) and ratio of ALA concentration to logarithm of
Cr
concentration (ALA/log Cr) were calculated and the relationship with Cr concentration was also examined.
The mean values of the ALA concentration and ALA/log Cr in urine of healthy subjects were 16.2μmol/l and 19.2μmol/l, respectively. No significant differences were noted in urinary parameters by age and sex. SG-adjusted ALA and ALA/Cr seemed to
be
an
inappropriate method for adjustment because the linear regression associations were noted between both adjusted values and Cr concentration. The value of ALA/log Cr was independent of the actual Cr concentration of urines within a wide range
(12-20.5mmol/l), which indicated that this adjustment method was simple and more reliable.
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