“…Typical data from the literature are shown in Table 3. 4 If diet does not affect the excretion Cor absorption) of heavy metals, solvent metabolites, etc, and if the rate of excretion C corrected for body size) is a true index of absorption, the specific gravity adjustment will lead to error when applied to urine specimens from persons with varying diets, particularly with respect to protein content. Assuming a constant excretion rate of heavy metal for subject D of Table 3, the specific gravity-adjusted values would differ markedly when on the different diets, as shown in Table 4.4 A sample taken on the low-protein diet would indicate twice as severe an exposure as that obtained on the diet rich in protein.…”