[Adjustment of urinary delta-aminolevulinic acid concentrations in workers exposed to lead and heat. Adjustments of specific gravity to 1.020 and urinary volume coefficients].

Adjustments of urinary ALA concentrations as to urinary specific gravity and creatinine were examined for workers exposed to lead and heat. Judging from our findings, we suggested that it was preferable to adopt the specific gravity (UG) at 1.020 as the adjustment value to obtain the correct urinary ALA concentration. Though corrected values thus obtained were found adequate for urine in the normal range of specific gravity, they failed to be adequate for concentrated urine samples higher than UG 1.025. Urinary volume adjustment was found to be necessary for these concentrated urine in stead of urinary specific gravity adjustment. For the practical purposes, we postulated urinary volume coefficients, which were estimated to be 0.5 for samples ranging from UG 1.026 to 1.030, 0.4 for samples from UG 1.031 to 1.035 and 0.3 for samples from UG 1.036 to 1.040, respectively.