What Is Contrast Agent induced Nephropathy? How Is It Defined and How Often Does It Occur?
In the most general terms, contrast agent induced nephropathy is the occurrence of renal failure, as indicated by an increase in serum creatinine level or a fall in calculated creatinine clearance, after the administration of an iodinated contrast agent. For several reasons, there is no widely accepted definition of contrast agent induced nephropathy. First, such nephropathy occurs essentially only in those patients who have abnormal renal function before contrast agent injection. Second, the parameters used clinically are imprecise. That is, serum creatinine levels vary with age, muscle mass, and gender. A serum creatinine value of 1.2 mg/dL in a healthy 20-year-old man or woman is normal and indicates that the glomerular filtration rate is in the normal range of 60 120 mL/min, most likely close to or above 100 mL/min. The same serum creatinine value in a 50-kg, 80-year-old woman, however, likely correlates with a significantly decreased glomerular filtration rate, perhaps even less t