CRP and SAA: Inflammation Markers in Dogs and Cats

CRP and SAA are proteins that the liver releases into the blood soon after inflammation starts. A blood test for them shows that inflammation is present and roughly how active it is, but it does not say what is causing it. CRP is the marker usually checked in dogs, and SAA is the one vets often choose for cats.

What are CRP and SAA?

Inflammation is the body's first reaction to a wound, an infection or other trouble. When it begins, the liver quickly makes extra amounts of certain proteins and sends them into the blood. Vets call these acute-phase proteins, where "acute" means early and sudden. CRP is short for C-reactive protein, and SAA is short for serum amyloid A.

These proteins climb fast, often within hours of the start of inflammation, and they fall again as the body settles down. That speed is why they are used as an early signal that something is going on inside a pet that cannot tell you how it feels.

Which marker is used in dogs and which in cats?

In dogs, CRP is the usual choice. The Canine C-Reactive Protein (cCRP) test is made for dogs, and the general C-Reactive Protein (CRP) test is listed for both dogs and cats. For cats, vets more often turn to SAA, and the Feline SAA (Serum Amyloid A) test is meant for cats only. Your vet picks the one that suits your pet.

Each test uses a blood sample from which serum is separated. Serum is the clear, yellowish liquid left when the blood cells and clotting parts are taken out.

What can the result tell your vet?

A result is a clue, and it can help in three ways:

• It may show that inflammation is likely present in a pet that looks dull or feverish but has no clear sign of where the trouble lies.
• It may show how strong the inflammation seems to be, by comparing the number with the reference range printed on the report.
• It can be repeated later, so the vet can see whether the pet is settling or slipping.

What the result cannot do is name the cause. An infection, a deep wound, an inflamed joint or a damaged organ can all push the marker up, so the same number may come from very different problems. A normal result is reassuring, yet it does not close the case, because a very mild or very early problem may not have raised the marker yet.

How do these markers help after surgery?

An operation is a planned injury, so some rise in the marker afterwards is expected. What matters is the direction it takes. In a pet that is healing well, the level usually climbs and then comes down as the tissues recover. If it stays high, or rises again after it began to fall, your vet may look harder for a problem such as an infected wound or trouble inside the body.

A sample taken before the operation gives a useful starting point for comparison. Even so, the number is only one part of the picture. A pet that is dull, off its food, feverish or in pain after surgery should see the vet promptly, whatever a lab report says. Never wait for a result when an animal is clearly unwell.

How do they fit with other tests?

A Complete Blood Count (CBC) counts the red cells, white cells and platelets. The white cells often rise when the body fights an infection, but the count can stay unchanged even when inflammation is present. Looking at the blood count and the inflammation marker side by side usually tells the vet more than either one alone.

Once inflammation is confirmed, the vet may add other checks to look for the cause, such as urine tests, tests for infections, scans or a sample from a lump or wound. A registered veterinarian reads all of this together with your pet's age, signs and history before deciding what to do next. That may mean starting treatment, repeating a test or adding other tests.

Read next

A cat with a high inflammation marker and no clear cause may be checked for several infections, and FIP and Feline Coronavirus: What an RT-PCR Result Means explains what an RT-PCR result can and cannot say about one of them. For a dog with fever and a history of ticks, Tick Fever in Dogs: Signs, Causes and Tick Panel Tests describes the tick-borne infections vets look for.

Testing in Bhopal

You can bring your pet to the lab at C-200, C Sector, Shahpura, or ask for the blood sample to be collected free anywhere in Bhopal. Owners in other districts can send samples by courier or bus parcel, or ask their own vet to send them. Call or WhatsApp +91 88175 01118, and the lab confirms the method, sample needs and reporting time when you book.