My dog has an elevated alkaline phosphatase. What does that mean?

dog with vet

There are several liver enzymes that veterinarians will check on a routine basis. The two most common liver enzymes checked are called ALT (alanine aminotransferase) and ALP (alkaline phosphatase). These enzymes come from different places in the liver, so the level of concern your veterinarian will have for your dog will vary depending on which enzyme is elevated and to what degree.

ALT should be tucked inside of the liver cell. When it comes out into the blood at higher than normal levels, this indicates that something is irritating the liver cell membrane, allowing the enzyme to leak out of the cell. Vets become concerned when this enzyme gets too high because it means that something is irritating or damaging the liver. There are a variety of reasons this enzyme can go up: infection, inflammation, toxin ingestion, a tumor and copper storage disease are all on veterinarians’ “rule-out” lists.  (Copper storage disease is a condition in which the body traps copper in the liver). A normal range for this enzyme is around 18–120 U/L (normal ranges vary by lab) and mild elevation in this enzyme is not uncommon, especially in older animals. Every veterinarian has a different comfort level for when to worry about this enzyme. For me, I start to get more concerned when the reading goes above 200.

ALP comes from a totally different spot in the liver, and changes in this liver enzyme typically cause less concern for veterinarians. (ALP also comes from the bone, so this enzyme is not liver specific. For the scope of this article, however, we will discuss ALP made by the liver). This enzyme is made on the liver cell membrane, and there are a variety of factors that can stimulate the liver to make more of this enzyme. The normal range for this enzyme is 5–160 U/L. For me, I start to get more concerned when this enzyme goes above 500. It is common to see this enzyme become very elevated in dogs that are otherwise acting normally. I have some patients that have an ALP in the 1,000–2,000 range and clinically appear healthy.

There are a variety of reasons that the liver will make more ALP enzyme. One common reason is that the aging liver will sometimes develop benign areas of liver growth called nodular hyperplasia. (You have probably heard that your ears and nose keep growing as you get older – so too will your liver grow new cells over time.) If there are more liver cells to make more of this enzyme, then the ALP will increase.

Another common reason for an older animal to have an elevated ALP is if they have Cushing’s disease.  Cushing’s disease (hyperadrenocorticism) is where the adrenal glands are producing more hormone then they should. These adrenal hormones influence the liver and turn on production of ALP.

Certain medications can also turn on production of ALP. One of the most notable medications that does this is a seizure medication called phenobarbital.  Phenobarbital can benignly cause an elevated ALP, but this medication can also cause liver damage. Because of this, it is common for veterinarians to want to do more testing on the liver if a dog has an elevated ALP and is taking phenobarbital so she can differentiate between a benign and toxic liver change.

It is not always a benign reason that the ALP is up. For example, the ALP will also go up in dogs if there is a gallbladder or bile problem, or a tumor in the liver.  Interpreting liver enzyme elevation is where the “Art of Medicine” comes in and the practitioner must take in the big picture of the pet and the desires of the client. If the pet is clinically normal, then monitoring may be recommended. If the pet is acting sick (drinking more, not eating, vomiting, panting or otherwise seeming unwell), or the client wants more information, then the practitioner may recommend further testing, like a liver ultrasound.

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  • Diana Barsotti

    What would the treatment be if Akko is out of range by 1948 u/l and it’s not crushing disease m?

  • Kim

    My dogs ALP is 1152. She is acting fine so the vet said let’s just watch her. Her urinalysis came back with 3+ in her urine though which is a worry to me. I have changed some things with her food and added some things to nourish the liver so hopefully next test is normal or close to being normal. It scares me though.

  • eastcoastelliott

    My dachshunds count is 566 so I was Concerned but your dog is much higher,

  • eastcoastelliott

    What did you purchase to aid the liver

  • Kim

    Yes I don’t think I’d be that concerned unless yours starts showing signs that come with elevated liver.

  • Kim

    I was given Denamarian advanced once a day from vet. Recently a dog food guru told me to add milk thistle as well so she gets both. Numbers previous to milk thistle were still off. I’m trying to figure out what to feed her but I’m hitting a brick wall on that.

  • Kim

    Milk thistle is in capsule form

  • Kim

    I’m not sure what Akko is?

  • Linda Davreux PREC

    Took my 5 yr old papillon/chihuahua to the vet beginning of January because he collapsed suddenly at the rear, appeared to be hip related, was very odd. I asked for a blood test, vet said luxating patella is the issue and I could consider surgery. Took him to another vet and asked for a blood test, They told me the same thing, took xrays and gave us anti inflamatories, did nothing, the rest of his body started to give out, they prescribed pain medication. I pleaded for a blood test. They said not needed. Then I insisted, they did the test in February and said his immune system attacking himself and put him on prednisone. He started to do alright but then not very well. After a couple months I asked for another blood test. They said not needed. This week I insisted. Now, my pup has an elevated ALP of 1347, ALT of 450 and platelet count of 592, comments on the test say variability in platelet size, numbers are increased platelets clumped.. I’m very worried. Now they’re telling me to reduce the prednisone substantially (they previously told me it must be done very gradually. the last time we tried to reduce we ended up having to double up on it again) Any advise would be greatly appreciated.

  • Jennifer Brooke Bogar

    I’ve got a dachshund whose ALPs have been climbing and he’s been on Denamrin and Urisoidol. Now they are recommending an ultrasound, which I am getting ready to do. Milk thistle alone appeared to help and then took him back and the ALPs had risen again. I’m praying daily. Any suggestions please. I am considering a second opinion as well.

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