Your Dog And Cat’s Albumin To Globulin Ratio – A:G Ratio

Ron Hines DVM PhD

To see what normal blood and urine values are for your pet, go here
For an explanation of causes of most abnormal blood and urine tests go here
To see how tests are often grouped, go  here 

This ratio number is the amount of albumin protein in your dog or cat ’s blood divided by the amount of globulin proteins in you pet’s blood. Albumin is the most common protein in your pet’s circulation.

When too much albumin is present, it is most often because your pet has become dehydrated.

When too little albumin is present, your pet may be nutritionally deprived; or its liver may no longer be working adequately enough to produce sufficient albumin.

The amount of globulin in your pets blood also affects its A:G ratio. When the amount of certain blood globulin  proteins in your pet is excessive  (hypergammaglobulinema ), its A:G ratio will be low. In that case, your pet’s immune system is either responding to a perceived threat or it is malfunctioning (a hyperplastic, precancerous or cancerous state).

When too little immune globulin is present, your pet’s immune system is not working adequately to produce sufficient globulin.

Dividing your pets blood albumin level by its globulin level to get its A:G (or A/G) ratio helps alert your veterinarian to an abnormality in either albumin or globulin levels. But that is of little value if your pet’s total blood protein (TP) is not known. But because globulin levels are usually determined by simply subtracting the albumin level from the total protein level, it would be difficult for your vet not to know your pet’s total protein value.

The albumin to globulin (A/G) ratio can be used to alert your veterinarian that an abnormal situation exists. However, it is not a marker for a specific disease because it does not, in itself, tell your veterinarian which specific proteins are at abnormal levels or suggest what the cause might be. Hopefully, some of the other blood tests that came back in the report will help with that.

Follow these albumin and globulin links to learn more about each and the things that cause their levels to go up or down.

Reasons Your Pet’s A:G Ratio Could Be High:

That can occur when your pet’s blood globulin level is abnormally low. You can read about some of the possible causes for that here.

Reasons Your Pet’s A:G Ratio Could Be Low:

You pet’s A:G ratio could be low because of low albumin (hypoalbuminemia) or high globulins (hypergammaglobulinemia).

Globulins often increase in chronic inflammatory diseases of pets. In cats that can be due to feline infectious peritonitis or FIP. However, as that disease progresses, decreases in albumin due to general health decline can bring A:G ratios closer to normal again (But the A:G ratio is still one of the few ways, baring multiplebiopsies, for your vet to add to his/her suspicions that your cat is suffering from FIP when inflammatory fluids are accumulating in its body or when neurological signs point to that disease; it is not that helpful when the cat’s symptoms are vague and might be due to a number of health issues [ref] ).

In dogs Ehrlichia and Leishmania infections as well as chronic colitis can cause high blood globulin levels.

Another cause of increased blood globulin in pets are globulin-secreting tumors (myelomas).

Your pet’s A:G ratio will also go down if globulin remains normal but albumin decreases – as sometimes occurs in liver disease, chronic kidney disease.

Chronic intestinal inflammation in dogs and cats (protein loosing enteropathies) can also cause low albumin levels (when albumin leakage exceeds any increase in globulin production that has occurred due to the chronic intestinal inflammation).

Dehydration will give abnormally high reading for both Albumin and Globulin – but the A:G ratio should remain unchanged.

Complementary Tests:

CBC/WBC, urinalysis ,blood chemistry panel, (for evidence of liver enzyme abnormalities when albumin is low) + ,bile acids, cobalamin and folic acid when intestinal loss of albumin is suspected. Fecal parasite check when intestinal parasites could be the cause of low blood albumin. Tick panels when systemic parasites like Ehrlichia are suspected.

When globulin is high or low, perhaps aProtein Electrophoresis and M:E ratio could be in order


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