just a shot in the dark but are you drinking enough water?
it could also be a lab error.
it could also be something else going on in your body, an infection somewhere.
that is a steep jump but it may be just a fluke and you should have labs redone.

Creatinine levels can fluctuate a lot. The only predictable is that it will continue to go up. Yours is a big jump, but, like spiderwoman wrote, it could be any number of things. I get tested every four months because I'm in the HALT study and I see my neph in between. I had a rather alarming jump a month ago and my doc asked if I had eaten steak or any other read meat prior to the draw. Possibly, I said. Well, don't do that, he said. Red meat is just muscle. So, I got re-tested a month later, drank so much water I, well, you know and, avoided high protien food for 24 hours. Result - creatinine back down to where it was in April.

So glad to hear that Lisa! Take good care!

Thanks a lot to you all. Am drinking lots of water now and will get retest done in 10 days.
Lets see, am hoping that it will come down.
Great to know Lisa that your creatinine went down.

I read your comments and appreciate what is said. I have to admit my diet needs to change. My nutritionist told me not to eat tins of baked beans or cheese. So now I will eat fish even if the seas are being plundered. I don't think there's a shortage of pilchards & sardines.
I'm stage 5 PKD and reached the stage where my kidneys can't produce red blood cells because they can not process iron. I am having iron infusion drips once a week because ferrous fumarate pills (iron) are no longer effective. I think it is important that PKD sufferers have to accept the fact that their time will come for dialysis and hopefully transplant. My next step is to have a vein connected to an artery in my arm, which will allow dialysis to be done regularly. I feel tired these days.

Post 10 days..antibiotic course is over..creatinine is still at 3.5 and cause for sudden jump unknown...how many unknowns do we need to deal with ?