[Creatinine and urine density as reference values in biological monitoring]

Creatinine and density of urine as reference parameters in biological monitoring Since in practice biological monitoring with 24-hour urine samples is not possible, a reference parameter is required. In two different experimental models - for 10 days in 24-hour portions and for 1 day with spontaneous individual fractions - creatinine excretion, mean daily urine volume and urine density were measured quantitatively in 5 healthy human subjects not exposed to chemistry. In the 10-day model, coefficients of variation were: 8.7% for creatinine, 24.9% for mean urine volume and 11.7% for urine density. In the 1-day model, coefficients of variation were: 15.8% for creatinine, 51.0% for mean urine volume and 28.0% for density. This indicates that the results of the second model are considerably more expressive than those of the first. It can be concluded that creatinine is the most suitable reference parameter. Density is less suitable and mean urine volume least suitable.