After contrast exposure, serum creatinine typically rises within what timeframe?

• A. 1-2 hours
• B. 24-48 hours
• C. 72 hours
• D. 1 week

Answer: (B)

The main idea here is the timing of the kidney’s response to contrast exposure. Contrast-induced nephropathy causes a drop in filtration that isn’t reflected in creatinine instantly; it takes some time for creatinine to accumulate as GFR falls. In most cases, serum creatinine begins to rise within about one day to two days after exposure, with a peak a few days later, and often returns toward baseline within a week or two if recovery occurs. That makes the 24–48 hours window the best match for when you’d first detect a rise in creatinine. The other timeframes either happen too early (creatinine isn’t detectable that soon) or are later than the typical initial rise.