ADJUSTMENT OF CREATININE-ADJUSTED VALUES IN URINE TO URINARY FLOW-RATE - A STUDY OF 11 HEAVY-METALS AND ORGANIC-SUBSTANCES

The use of urinary monitoring in medical surveillance programs in indu stry requires development of an accurate and unbiased index of urinary concentrations of occupational toxins, To examine the effects of urin ary flow (UF) rate on the standard creatinine (Cn)-adjusted value and the UF- and Cn-adjusted values according to Greenberg and Levine and t o Araki et al, for 11 heavy metals and organic substances, 19 metal-fo undry workers aged 34-59 years (mean 48), who had been exposed to lead , zinc, and copper for 2-17 (mean 10) years, were studied during four periods of the day under water-free, water-restrictive and water-loadi ng conditions for 6 days, The blood lead concentrations of the 19 work ers ranged from 22 to 59 (mean 38) mu g/dl. The results indicated that there was no significant UF effect on the UF- and Cn-adjusted values of Araki et al, for all urinary substances except mercury and copropor phyrin, On the other hand, the UF- and Cn-adjusted value of Greenberg and Levine was positively correlated with UF rate for all urinary subs tances, and the standard Cn-adjusted value was either positively or in versely correlated with UF rate for many urinary substances. Therefore , the UF- and Cn-adjusted value of Araki et al, is considered to be ap plicable to the measurement of most urinary substances under condition s of wide variation in UF rate.