Does anyone know where i can find a comprehensive breakdown of blood testing results for cats ?

My 2 year old male cat has been diagnosed with renal failure level 1 based on the fact that his creatine level is up to 2.5 and the doctors indicate that it should be under 1.8. The problem is I've been for a 2nd opinion, I just don't feel confident with this diagnosis. The bloodwork and urinalysis are otherwise normal. No elevated bun, high spec gravity, normal cal and phos levels.The cat drinks a lot, but he always has. He behaves normally. He does have a tapeworm infestation that is being treated, and he always has a good appetite despite a slightly sens stomach. He uses a nonclay litter and ate a high quality dry diet until he was put on kd last month. I've read that creatine is a muscle byproduct, I'm wondering if his creatine spike could have anything to do with some sort of muscle trauma or inflamation that has not been obvious. He had two sets of shots the weeks before the first elevated blood test. 2 more blood tests have been done confirming the 2.5 level twice. Any ideas?