The information contained in this article is provided for educational purposes only and is not intended to replace veterinary advice. Please consult with your vet for further information.


Cat ketones diabetic ketoacidosis


Ketones occur when the body cannot access blood glucose for energy.  Untreated ketones can lead to a life threatening situation, a diabetic keto-acidosis or DKA.

A DKA is an emergency situation, and vet care is essential.

Catching ketones at low levels and taking appropriate action can save your cat’s life. 

It is important to test for ketones if your cat is over renal threshold (225-250/12.5-13.8 for most cats).

Ketones are a direct result of hyperglycemia (high BGs).  Ketones can develop because of not enough insulin, too much insulin, illness, infection, and/or anorexia.

What are ketones?

Normally, cells get the energy that they need to function by using blood glucose.  Insulin plays a vital role in the process:  it is the key that unlocks the receptors on cells, letting them access the needed glucose.

Cells are unable to do that when there is either insufficient insulin, or when insulin resistance has built up and the receptors are no longer receptive to the insulin present – the key doesn’t unlock the cell.

As it can’t find its usual source of energy, the body turns to the next available source and starts burning up muscle and fat for energy.  The liver responds to the situation by secreting ketones and glycogen (pushing glucose levels higher in the process).

When the level of ketones is too high to be used, they start building up in the blood stream.

As this continues, the ketones end up being too much for the body to absorb, and spill into urine.  At the same time, they upset the acid balance in the body, leading to imbalances in electrolytes .. and, if left unchecked the result is a DKA (see below).

When should you check for ketones?

Ketones are most commonly present when blood glucose levels rest over renal threshold (around 250/13.8).  Some cats are more sensitive than others, and will show ketones at lower levels and in a short period of time, others need to be in higher numbers for longer… and some just seem to be relatively immune to them.

You should systematically be checking your cat for ketones if he is in numbers over renal threshold (at least once a day).

Ketones can also occur in lower numbers however:  infections, pancreatitis, heart disease or stressful situations can also lead to ketones.  If your cat is unwell, you need to check for ketones even if he is in normally “safe” numbers (over normal numbers for a non-FD cat but under renal threshold: 150/8.3 – 250/13.8).

A cat that is not eating well – usually as a result of an infection, pancreatitis, etc –  is also more at risk for ketones and should be monitored.

How do you check for ketones?

Checking for ketones can either be done via urine strips or certain glucometers will also test for ketones.  The test strips for meters that do so are very expensive, and are not necessary in most cases – the urine strips give accurate ketone results.

Blood ketone testing meters though can be good to use if your cat has shown that it is prone to ketones, or has suffered DKAs in the past.  The blood ketone test will show the presence of ketones earlier than the urine testing will.

Urine Ketone Testing

Urine ketone testing is done with keto-diastix (which measure both urine ketones and urine glucose) or keto-stix (which measure urine ketones only).  These are available in any pharmacy or chemist, and are not expensive.

To use the urine strips, the best thing to do is to try and place them under the urine stream as your cat is urinating – this can take some practice!  Some people have had success putting a ladle or long handled spoon under their cat as it is urinating.  Alternatively, press the strip into the litter just after your cat has urinated.  It can help to put a minimal amount of litter in the box so that you have a pool of litter to dip the strip into.

The urine does need to be fresh to give accurate results.

It is very important to count off the exact number of seconds indicated in the instructions of the Keto-Diastix/Keto-stix you have purchased.  Reading the results too soon will give falsely low results…. Waiting too long will give false high results.

Results are read by comparing the colour on the test strip with the colour on the canister:

ketodiastix in png

Blood Ketone Testing

Several brands do have models that will let you test both blood glucose and ketones today.  Specific ketone testing strips are necessary to test for ketones on your glucometer;  they are usually quite expensive.

Blood ketone testing does allow an “immediate” result – ketones are present in the blood before they spill over in the urine and are picked up by urine ketone testing strips.

Being alerted early to the presence of ketones can be important in cats that develop ketones quickly, and for those that have suffered from DKAs (in particular if recently).

Testing is done in exactly the same way as when testing for blood glucose:  the ketone test strip in the meter is simply used in place of the blood glucose test strip.

Some ketones can be present normally in the blood, so a positive/over 0 result is not a reason to panic!

Urine vs. Blood Ketone Results and Actions Needed:

excel urins vs blood ketones

Please post on Introductions & Questions, where an experienced member will help you decide what is the best course of action for your cat given his circumstances.

Lower level ketones may be possible for you to handle without vet intervention :

  • If you are testing glucose levels at home
  • If your cat is on 100% low carb wet food
  • If your cat is acting normally (not lethargic, eating…)
  • Depending on the situation: what level your cat’s BGs are and have been, past history of DKA…..
  • Depending on what type of insulin you are using: a medium action insulin (Caninsulin, US/Canadian bovine PZI, ProZinc, NPH) or a longer action one (Hypurin Bovine PZI, Lantus, Levemir)

If your cat is showing moderate or higher levels or is showing any of the following symptoms, it is a medical emergency, and you should get him to a vet right away.  They are symptoms of a life threatening DKA:

  • Lethargy
  • Vomiting
  • Diarrhea
  • Dazed, spacey, “out of it”
  • Will not eat or drink
  • Acetone breath (may smell a little like apples or nail polish)

If you have any questions about ketones or DKA, or if you have tested for ketones and the results are positive even at a low (trace) level, please post on Introductions & Questions for immediate assistance.

For more information about a DKA, please read the DKA Article in the Knowledge Centre.


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