Contrast-induced nephropathy is defined as an increase in serum creatinine of 25% or more within two days of receiving radiographic contrast. The measurement of serum creatinine indicates the level of kidney functioning. The Contrast-Induced Nephropathy Trial at Kaiser Permanente compared two ways of preventing nephropathy (a disease of the kidneys) in patients undergoing cardiac catheterization, a procedure during which they received radiographic contrast. One preventative method was hydration with sodium chloride through IV fluids, while the other was hydration with sodium bicarbonate through IV fluids. Creatinine levels were recorded the day of catheterization, on day one post-catheterization and on day two post-catheterization. If a patient's creatinine levels increased (meaning their kidney functioning decreased), creatinine levels were recorded between four days and eight weeks after catheterization. In this manner, the effect of radiographic contrast on kidney functioning was monitored and the rate of contrast-induced nephropathy was recorded when treated with both sodium chloride and sodium bicarbonate. Interim data analysis shows an insignificant difference in the rate of contrast-induced nephropathy between the two groups. Thus far, there is no difference between the benefit of hydration with sodium chloride and hydration with sodium bicarbonate in the prevention of contrast-induced nephropathy.