Petlife heart logo


Would you visit the veterinarian more frequently if:

View Results

Loading ... Loading ...


Lions Foundation of Canada Dog Guides and its founding program, Canine Vision Canada, was established in 1983. It’s the largest school of its kind in Canada with its training school in Oakville and breeding facility in Breslau.


Stages of Feline Chronic Kidney Disease

Chronic kidney disease is staged depending on the severity. This is estimated based on the level of waste products in the blood and abnormalities in the urine.

The International Renal Interest Society (IRIS) developed a method to gauge the severity of the disease in four stages. Stage 1 is the least severe and Stage 4 is the most severe. Staging the disease is useful for treatment, monitoring and management of the disease.


  • This means that the cat’s kidney function is somewhere between 33% and 99%. It is difficult to identify kidney disease until later stages.
  • This is usually diagnosed by seeing a cratinine less than 1.6 on blood work, but seeing other signs of kidney disease such as low electrolytes, dilute urine, excess protein in the urine, or small or misshapen kidneys.
  • We do not typically see any clinical signs or symptoms at this stage.
  • Most cats who are diagnosed with stage I CKD can have several years before it progresses to stage II CKD, but every cat progresses at a different rate.

As you might guess, once a cat is in stage I of chronic kidney disease (CKD), kidney function is no longer at 100%. It might still be at 99%, but it can drop to as low as 33% (in other words 67% loss of kidney function).

Although there’s a lot you can do for your cat if he or she is in stage I of CKD, you probably won’t even realize that you should because seeing the signs during this time is rare. Tests are usually required to diagnose CKD this early, but testing cats that look healthy is not common practice.


  • This stage means that the cat’s kidney function is somewhere between 25% and 33%. The kidneys are still adequately filtering out toxins and waste products, but they are starting to struggle.
  • This is usually diagnosed by seeing a creatinine level between 1.6 and 3.0 and seeing low electrolytes on blood work.
  • Some symptoms at this stage may be more water intake, and a little more urine output and hypertension.
  • At this point treatment becomes a little more aggressive, but with treatment, we can prolong stage II CKD for several months to several years.

At stage II, cats have about 25% to 32% of kidney function left (in other words up to 75% of kidney function could have been lost already). The kidneys are still able to perform their roles, but the performance is not optimal. They specifically struggle to conserve water and electrolytes such as sodium, potassium and chloride.

Cats in stage II of CKD will typically experience increased thirst and therefore need to drink more water. They will also produce more urine and urinate more frequently. They may even urinate in inappropriate places. A reduction in appetite, weight and energy levels may become apparent in this stage or otherwise in stage III. Once you’ve told your veterinarian about the symptoms, he or she can test creatinine and electrolyte levels as well as blood pressure to confirm or rule out CKD.


  • This stage means that the cat’s kidneys are now functioning between 15% and 25%. At this point, the kidneys are no longer able to adequately filter out all of the toxins and waste products of the body, and the cat may be starting to develop more noticeable symptoms of kidney disease.
  • This is diagnosed by seeing a creatinine level between 3.0 and 6.0 and abnormal electrolytes on blood work.
  • There is moderate renal azotemia, which is the accumulation of waste products in the blood
    (a measure called BUN, or blood urea nitrogen), and probably other symptoms are visible as well.
  • The primary symptoms are increased drinking and urination, increased nausea, which will usually manifest as decreased appetite, being pickier with foods, and an increase in vomiting. Hypertension is often present, and cats are more prone to secondary bladder infections.

During stage III, cats can lose up to 85% of kidney function. Now, the dangers are very real and without proper treatment the inevitable will happen much sooner. The same tests that can help diagnose CKD in stage II can be used once more and by now the creatinine and electrolyte levels will be even more alarming.

The same signs that may have already surfaced in stage II may become more severe, but other things can start to happen as well. In stage III, a cat’s coat may seem worse for wear. Bladder infections, nausea and vomiting are also not uncommon.

If a treatment plan has not already been designed and implemented, it should be prioritized immediately.


  • This stage means that the cat’s kidneys are now functioning at less than 15% and 25%.
  • There is severe renal azotemia, which is the accumulation of waste products in the blood
    (a measure called BUN, or blood urea nitrogen), and probably other symptoms are visible as well.
  • The focus is on supportive care and increasing quality of life. This is diagnosed by seeing a creatinine level higher than 6.0, and in most cases, an elevated phosphorus level.
  • The primary symptoms at this stage are extreme nausea, to the point of not eating, and lethargy.

The amount of protein passed in urine and the presence of elevated blood pressure are also factored into the staging process. 

Symptoms in a cat with stage IV CKD cannot be missed. More than 85% of kidney function has been lost and the irreversible damage is at its peak. Cats that have reached stage IV don’t have much longer to live, perhaps not even a year.

By now, additional symptoms can include dark urine, diarrhea, bloating, lethargy, mouth sores, bad breath and anemia. Quality of life has greatly declined in stage IV.

Managing the disease may not be as effective anymore and supportive treatment may not be enough. You need to make a decision about your cat’s condition and how long he or she can endure it.

previous arrow
next arrow
Print Friendly, PDF & Email