Cystatin C and serum creatinine in estimating acute kidney injury of shock patients.

BACKGROUND Serum creatinine (SCr) is the most commonly used parameter to estimate renal function impairement, but there are some shortcomings. Many factors including age, gender, drug, diet, muscle mass and metabolic rate can influence SCr, leading to an inaccurate estimation of kidney impairment. Studies have shown that cystatin C (CysC) is not affected by factors such as muscle mass, age, gender, diet, inflammation or tumor. The present study was undertaken to compare the sensitivity of CysC and SCr in evaluating renal function impairment at early stage of shock. METHODS Seventy-one patients aged 38.3±21.4 years, who had been treated at the Emergency Medicine Department of the First Affiliated Hospital, Sun Yat-sen University between February 2006 and June 2007, were studied. They were divided into groups A, B, C, and D according to the shock time. Serum sample was drawn from each patient at 1, 2, 3, 4 hours after shock to determine SCr and CysC. CysC and SCr were determined again at 72 hours and 7 days after shock. RESULTS CysC increased earlier than SCr in the 71 patients, and CysC decreased slower than SCr when shock was corrected. CysC increased at 1 hour after shock. There was a negative correlationship between CysC, SCr and glomerular filtration rate (GFR), especially at early stage of shock. CONCLUSIONS There is renal injury at early stage of shock. CysC is more sensitive than SCr in assessing renal function at the early stage of shock.