Albumin/globulin (A/G) ratio in cats and dogs
The albumin/globulin ratio (A/G) is albumin divided by globulin. It is calculated from other lines of the form and has no unit. It helps to see which of the two protein groups has moved when total protein is high, low or deceptively unchanged.
What it shows
Total protein and albumin are measured; globulin and the A/G ratio are calculated from them (eClinPath). Very roughly, eClinPath puts the ratio in most species at about 1:1. A ratio below the range means relatively little albumin, a lot of globulin, or both; a ratio above the range means the opposite. The ratio alone does not say which happened — that is read from the albumin and globulin values themselves.
eClinPath stresses that the ratio can be interpreted only in light of total protein. The same ratio can arise in very different situations, and a ratio in range can hide a fall in both groups at once.
Higher than reference — what it may be a sign of
- Low globulins: a high ratio means globulins are low relative to albumin — for example in young puppies and kittens, whose globulins are naturally lower, with rare inherited immunodeficiencies, or with an artefact of overestimated albumin (eClinPath).
- Not dehydration: dehydration raises both groups, and total protein goes up while the ratio stays normal (eClinPath).
Lower than reference
- Excess globulins: with high total protein a low ratio indicates hyperglobulinemia (eClinPath) — chronic inflammation or infection, FIP in cats, tumours of antibody-producing cells.
- Selective albumin loss: through the kidneys (protein-losing nephropathy), where globulins are usually kept, so the ratio falls (eClinPath).
- Less albumin made: liver failure or inflammation, during which the liver produces less albumin.
Look at together with
- Albumin and globulin — which of the two changed.
- Total protein — the context the ratio is read in.
- UPC — when albumin is low and the ratio falls, checks for protein loss in urine.
- Protein electrophoresis — when globulins are high, shows which fractions are responsible.
Units and conversion
A/G is a ratio of two values in the same units, so it has no unit of its own and needs no conversion: it is the same whether the form uses g/L or g/dL. Forms print it as a decimal number or as A:G. If the form does not print it, it can be worked out by dividing albumin by globulin.
Reference range
The reference range is on your lab’s form, if the lab prints the ratio at all — some forms leave it out. Because it is calculated, any error in total protein or albumin carries over into globulin and into the ratio (eClinPath). In fluid drained from the abdomen or chest of cats with FIP, Merck describes a high protein content with an A/G ratio below 0.4; that threshold refers to the effusion, not to blood.
Cats and dogs
In cats high globulins in FIP lower the ratio. But a low ratio is not specific: chronic infection, lymphoma and multiple myeloma also raise globulins (Merck), and no single blood test confirms FIP (Cornell Feline Health Center). Kittens up to about 8 weeks have lower globulins, which shifts the ratio upwards.
In dogs the ratio helps to separate where protein is going. Protein loss through the kidneys usually takes albumin while globulins remain, so the ratio falls; protein loss through the gut usually takes both groups, so the ratio may stay in range (eClinPath). Chronic infections such as ehrlichiosis raise globulins and lower the ratio.
Add a lab form — Pet Tracker Space recognises the lines, keeps the form’s units and draws each indicator over time with your lab’s reference band.
Sources
This page explains what a lab value means. It is not a diagnosis and not a substitute for your veterinarian — only they can interpret results for your pet.