Sixty critical ill patients were investigated at admission in a mixed ICU.
CysC is a reliable indicator of severity compared to the APACHE II score.
GFR estimates based on CysC are also good predictors of severity in adults in an ICU.
Larsson equation was superior to Cockcroft–Gault as an indicator of severity of illness.
We confirmed a greater accuracy of Cockcroft–Gault compared with MDRD equation.