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Home > Diagnosis > Which Tests to Have, and How Often



  • If your vet suspects that your cat has CKD, s/he will usually run some tests to confirm the diagnosis.

  • The various test results will also tell you and your vet where any imbalances exist, which will help you to decide on the best treatments.

  • This page gives an overview of the various tests (which are covered in more detail elsewhere on the site) and explains which are the most important and how often these tests should be run.

  • The tests will give you some idea how severe your cat's case is, but they are not the whole story — treat the cat, not the numbers.

Types of Test


There are a number of different tests available. I know tests can be stressful both for your cat and your wallet, but they are invaluable in deciding how to treat your cat most effectively. Not every problem is apparent from the cat's behaviour. Once you know what problems your cat is experiencing, you and your vet can tailor the treatments to meet his or her needs.


Most vets who suspect CKD will run tests on your cat's blood, but they may also run urine tests.


They should do a blood pressure check but unfortunately not all vets seem to suggest this.


Occasionally your vet may suggest an ultrasound, for example if s/he suspects that your cat has kidney stones, or a kidney infection, or cancer.


Which Tests to Have


Initially some vets only test a measure of kidney function called blood urea nitrogen (BUN) or urea, or possibly BUN together with another test of kidney function called creatinine. However, if you get to choose which tests are run, I recommend that you ask for the following tests to be run as a minimum:

Blood Tests


These days your vet should be able to run most of these tests in-house and have results within a couple of hours, which can be helpful if your cat is very sick.


However, it is unlikely that they will be able to perform some of the more specialised tests, and their machines may not be calibrated as frequently as in a professional laboratory. See Factors that Affect Test Results for more on this.


I do have most of my cats' tests performed in-house though, mainly because it is faster. I think if you always have them run on the same machine, this is probably fine.


Where to have blood tests run can be a bone of contention. Many vets like to whisk the cat "out the back" away from you to have blood taken. This may be because it can sometimes be quicker (some cats freeze when away  from their human which makes it easier for the person drawing blood), or you may be told it is for liability reasons. I personally prefer to have blood taken in my presence (usually in the consulting room), particularly since one of my cats collapsed and died after having blood drawn "out the back." I think my cats are calmer and less stressed in my presence, and I am happy to sign a liability waiver if required. These days my vet's practice does routinely offer blood draws in the consulting room, thank goodness. See below for how to help cats who fight blood draws.


Blood Chemistry Panel


This is the most common type of test run on CKD cats.


This group of checks examines kidney function. It also looks for any other abnormalities associated with poorly functioning kidneys such as  electrolyte imbalances, metabolic acidosis and phosphorus/calcium imbalances. It usually includes other tests such as albumin, glucose and cholesterol. There is more detailed information about all these tests here.


Kidney Function

Blood Urea Nitrogen (BUN) or urea

Creatinine (Crea)


Electrolyte Imbalances

Potassium (K+) Many vets do not seem to check this routinely, but it is often low in CKD cats

Sodium (Na+)

Phosphorus/Calcium Imbalances

Phosphorus (P or Pi)

Calcium (Ca)

Metabolic Acidosis

TCO2 (or CO2), a test for metabolic acidosis (if possible - not every laboratory can do this test)

anion gap

Complete Blood Count


This is also a blood test, and is often run on CKD cats. CKD cats often have anaemia, so this test checks for that, and also looks for infections.


Red Blood Cells: Anaemia

Packed cell volume (PCV) or Haematocrit (HCT)

Helps to determine if the cat is anaemic and how severe it it.


White Blood Cells: Infection or Inflammation

White blood cells

Can help determine the presence of infection or inflammation.




As the name suggests, this examines the cat's urine. The following tests can all be run from one urine sample.


Urine Concentrating Ability

Urine specific gravity

CKD cats struggle to concentrate their urine so the USG test can help to confirm the CKD diagnosis, though a low USG may also be caused by other health issues).


Protein in the Urine


Urinalysis also shows if protein is present in the cat's urine. This is important to know, because they may make the CKD progress faster.


Pyelonephritis or Urinary Tract Infections



Blood Pressure


Many CKD cats have high blood pressure (hypertension) which can cause blindness among other problems, so it is really important to check for this. There is a page devoted to hypertension, which is diagnosed via a blood pressure monitor.


If your vet does not check your CKD cat's blood pressure, ask for it to be done.




This is not routinely performed on CKD cats, but may be offered if your vet suspects a kidney infection, kidney stones or a genetic condition called Polycystic Kidney Disease (PKD).


Specialised Blood Tests


These tests are not always necessary, but may be appropriate for some CKD cats.


These tests can usually only be run at specialist laboratories or vet schools, and can take 1-3 days to come back.


Hyperthyroidism (an Overactive Thyroid)



spec fPL

Parathyroid hormone and ionised calcium levels


Ionised calcium

Frequency of Testing


I am quite surprised how many vets seem to diagnose CKD at one visit, then say they do not need to see the cat again for 3-6 months. This may be possible for cats with very early CKD and few abnormalities in their test results. However, in most cases I think your cat will probably need to visit the vet pretty frequently, at least until any imbalances are under control and your cat is stable.


You should then be able to reduce the frequency of your visits, though of course you should always go to the vet if your cat seems sick or in pain.


Try to balance the need to run tests in order to monitor and control disease progression with the need to not increase your cat's stress levels unnecessarily, and bear in mind that taking blood too frequently can worsen anaemia.


First 1-8 weeks

Your vet will probably want to monitor your cat's kidneys values. It is also important to monitor the following:

You may not necessarily need to see the vet every week, how often will depend upon which issues you are dealing with. If you are trying to control a particular problem, it is reasonable to test these every couple of weeks until you have got things under control. Some tests, such as checking blood pressure, can be performed by a vet tech or vet nurse, which should be cheaper.


Once your cat seems stable, I would recommend checking bloodwork, urine and blood pressure at the vet as follows:


Every 1-3 Months

If your cat's creatinine level is in IRIS Stage 2 or above (creatinine above 1.6 mg/dl USA, 140 µmol/L international), I would ask for tests every 1-3 months. All the above tests (under 1-8 weeks) should be performed as appropriate, along with dental checks.


Every 3-6 Months

Six months is the maximum length of time I would go between vet visits. Personally I would feel more comfortable with three monthly visits, but every 3-6 months may be appropriate for cats in early stage CKD (creatinine below 1.6 mg/dl USA, 140 µmol/L international) who are stable. All the above tests (under 1-8 weeks) should be performed, along with dental checks.


ISFM consensus guidelines on the diagnosis and management of feline chronic kidney disease (2016) Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I, Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine & Surgery 18(3) pp219-239 states Following diagnosis (and stabilisation, if necessary), initial re-evaluations should typically be undertaken every 1-4 weeks, according to clinical needs. Full monitoring will not be necessary at each visit (and not all evaluations are needed in all cats and at all times), but should be performed sufficiently frequently to allow good patient management. Even in cases of early and apparently stable CKD, initial monthly revisits can be helpful in supporting the diagnosis, providing support to the owner, and in monitoring progression and therapy. In the long term, even if stable, cats should be re-evaluated at least every 3-6 months. Particular attention should be paid to appropriate monitoring of the efficacy of interventions to ensure that therapeutic targets are being met. In advanced disease, care may be needed to avoid exacerbating anaemia by too frequent blood collection."


Home Checks

In  all cases, do your own checks at home, e.g. regular weighing, monitoring of food intake. if your cat seems to be deteriorating or you have any concerns, you should seek your vet's advice regardless of whether tests are due.


Thomas was tested every week initially until his severe anaemia and high phosphorus levels were under control. We then switched to three monthly, but as the disease progressed we switched to every 1-2 months, then more frequently again as he worsened. In retrospect, I think we should not have switched to three monthly, bearing in mind how high his kidney values were at diagnosis.


If Your Cat Fights Blood Draws


Many cats find having blood taken very stressful. There are some ways to minimise this stress:

  • Stay with your cat whilst the blood is drawn. Many vets like to take the cat "out the back" to draw blood but this may frighten the cat, whereas a familiar face (yours) can help keep the cat calm. Catalyst Council has a couple of videos about examining the cat with their guardian present and tips on examining a fearful cat. However, as Vetstreet explains, some cats may be calmer away from their owner.

  • For cats who fight blood draws like our Harpsie, it can be easier to take the blood from a hind leg rather than from the jugular vein in the neck. Our vet used to place a towel over Harpsie's head and draw blood from the leg. You would probably expect a towel over the head to make a cat freak out more but many cats find it calming. Taking blood this way takes longer than taking it from the jugular but overall it still worked better for Harpsie. 

  • Cats hate the smell of alcohol, so it is better not to dampen down their fur with alcohol before a blood draw because it increases their stress levels. It is unnecessary anyway unless your cat has a particularly weak immune system, e.g. s/he also has cancer. Critical Care DVM says "It is not necessary to “sterilize” the skin with alcohol prior to inserting the needle. In reality, wiping a little alcohol on the skin does not sterilize it, and the odor and feel of alcohol may aggravate your pet."

International Cat Care is promoting cat friendly clinics to try to reduce stress for cats during vet visits.


Keeping Records


Not every vet routinely offers copies of test results to clients, but if yours doesn't, ask for them. They will probably be meaningless gobbledegook to you at first but don't worry, you will soon learn which are the important readings and what they mean.


Keep your own records of your cat's symptoms and bloodwork results, so you can monitor trends and have records you can take with you if you have to take your cat to the ER or to see a specialist. See Working With Your Vet for more information.





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This page last updated: 22 June  2021

Links on this page last checked: 22 June  2020










I have tried very hard to ensure that the information provided in this website is accurate, but I am NOT a vet, just an ordinary person who has lived through CKD with three cats. This website is for educational purposes only, and is not intended to be used to diagnose or treat any cat. Before trying any of the treatments described herein, you MUST consult a qualified veterinarian and obtain professional advice on the correct regimen for your cat and his or her particular requirements; and you should only use any treatments described here with the full knowledge and approval of your vet. No responsibility can be accepted.


If your cat appears to be in pain or distress, do not waste time on the internet, contact your vet immediately.



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