Can high calcium and potassium in blood taken 4 days after contrast CT scan be caused by the contrast? Normal creatine and urine test

Yes. Newer contrast today withnon-ionic iodonated contrast has less potential for side effects compared to the older generation of contrast. However, contrast-induced nephropathy can occur within anywhere from 1-5 days, with incidence of 0-40% depending on your risk factors, such as pre-existing diabetes, metformin usage. Potassium and calcium levels can increase due to decreased kidney function.
Elevated ca /K. Would repeat the test, make sure you are hydrated. Common cause of elevated potassium(k) is hemolyosis (red blood cells sheared). When potassium is above 6 we repeat it almost immediately. I am not aware of effects on calcium. Parathyroid issues,calcium intake,Vit D, cancer, rare conditions can cause elevated calcium. When was your previous testing and what were results? Hope this helps.