Systemic Levels of Cystatin C in Critically Ill Patients with Acute Renal Failure Requiring Hemofiltration.

Critically ill patients admitted in ICU are at high risk for developing acute
renal failure and 4-6% will require some form of renal replacement therapy. It
is difficult to predict residual renal function when patients are treated with
hemofiltration. Indeed, plasma creatinine and urea are removed by the filter,
and thus are useless for determine residual renal function.
Cystatin C is a protein produced by all nucleated cells at a constant rate,
independent of age, gender and muscle mass. It is completely filtrated in the
glomerulus and metabolized in the tubulus. In addition, plasma cystatin C
concentrations are not influenced significantly by hemofiltration.
The serum CysC concentration has been advocated as a marker of residual renal
function in patients with renal failure while being treated with HF.

To evaluate whether (changes in) systemic CysC-concentration can be used as a
marker for improvement of the renal function in critically ill patients while
treated with HF.

Multicenter, observational study.

Blood specimens are collected twice per week thereafter until end of stay in
ICU; urine samples are collected at the same time points, per sample 5 cc of
blood is obtained. In addition, urine samples and ultrafiltrate samples are
obtained.