do subq fluids temporarily change test results?
My ckd stage 4 cat’s bloodwork was showing some improvement last week, but today his bun and creatinine went up a little, and I’m trying to understand whether the timing of his subq fluids could have affected the results.
Last week, he had his blood drawn approximately 2–3 hours after we gave him subq fluids. This week, it was about 12–15 hours after his last dose.
The thing is, he’s genuinely doing so much better. His anemia has pretty much gone away, he’s eating well, gaining weight, playing, and seems to be in a really good mood. Honestly, if you saw him, you probably wouldn’t even realize he was sick.
So I’m a little devastated that his bun and creatinine didn’t continue to drop this week. I had really hoped we’d see improvement there too.
Could the difference in timing of the subq fluids explain some of this? If we had given him his fluids 2–3 hours before the blood draw again, like we did last week, would we potentially have seen lower bun and creatinine levels?
I know the fluids don’t actually improve kidney function, but I’m wondering how much they can temporarily affect bloodwork, especially bun and creatinine.