Protein electrophoresis in cats and dogs
Protein electrophoresis splits the proteins of serum into five bands — albumin and four groups of globulins — and shows each as a share of the total. It is usually ordered when globulins stay high without an obvious cause. The shape of the curve narrows the search: many antibodies rising together points to inflammation, while a single tall spike raises the question of a tumour of antibody-making cells.
What it shows
In a gel or a thin capillary, proteins move in an electric field at different speeds depending on their size and charge. The result is a curve; the area under each part is that fraction’s share, in percent.
- Albumin — a single protein, the most abundant in serum. It moves furthest and forms one sharp band.
- Alpha-1 and alpha-2 globulins — mostly acute-phase proteins made by the liver, such as haptoglobin. They rise within hours of tissue injury or inflammation, mainly in the alpha-2 band.
- Beta globulins — a mixed group: transferrin, complement, some lipoproteins and some antibodies (IgM, IgA and certain types of IgG).
- Gamma globulins — mainly antibodies (IgG), made by lymphocytes and plasma cells. They rise slowly, because an antibody response takes about 7–10 days.
Higher than reference — what it may be a sign of
- Alpha-2 up — an acute-phase response to inflammation, injury or infection. In dogs, glucocorticoid medicines raise haptoglobin and can create an alpha-2 peak by themselves, so the vet asks what the animal is taking.
- Polyclonal gammopathy — a broad hump across the beta and gamma region, wider than the albumin peak: many different antibodies rising together. It follows antigenic stimulation — infection, chronic inflammation, chronic liver, skin, gut or airway disease — and is not specific to any one disease.
- Monoclonal gammopathy — a tall, narrow spike in the beta or gamma region: one clone of cells making one antibody. Classic causes are multiple myeloma and other plasma cell tumours, B-cell lymphoma and chronic lymphocytic leukaemia. A monoclonal-like picture has been described with Ehrlichia canis and heartworm, so they are ruled out first.
- Restricted (oligoclonal) pattern — a narrow peak on a broad base. It is seen with some infections and inflammations (ehrlichiosis, leishmaniasis, FIV, FIP) and can look like a monoclonal spike; an extra test, immunofixation, tells them apart.
Each pattern is a clue, not a diagnosis.
Lower than reference
A low albumin fraction usually mirrors low albumin on the chemistry panel. A low gamma fraction means fewer antibodies: it is expected in young puppies and kittens, and it can follow protein loss through the gut or bleeding. With tumours that make one antibody, the other, uninvolved antibodies are often decreased. Electrophoresis is a poor test for confirming immunodeficiency: it does not measure individual antibody classes.
Look at together with
- Total protein, albumin and globulin — electrophoresis is usually ordered because globulin stays high; total protein turns percentages into amounts.
- A/G ratio — a low ratio is often the first hint of excess globulins.
- Feline coronavirus tests in cats, Ehrlichia and Leishmania tests in dogs — infections that change the globulin pattern.
- CRP and SAA — specific acute-phase proteins; SAA is present in amounts too small to show on electrophoresis.
Units and conversion
Each fraction is reported as a percentage of total protein (%); many labs also print the amount of each fraction in the same unit as total protein, calculated as total protein × percentage. The app stores the percentage. Agarose gel and capillary methods give similar numbers but different peak heights, and dividing the curve into bands is partly subjective, so a series is best compared within one lab and method.
Reference range
The reference range is on your lab’s form, and it is species-specific: labs keep separate intervals for dogs and cats. More than the exact percentages, the vet looks at the shape of the curve — whether a rise is a broad hump or a narrow spike. A suspected monoclonal spike is usually confirmed with immunofixation, which identifies the type of antibody. Serum is the right sample: in heparin plasma, fibrinogen forms a peak in the beta region that can mimic a spike.
Cats and dogs
In cats with FIP, a typical combination is an acute-phase rise of alpha-2 globulins together with a polyclonal gammopathy; electrophoresis of abdominal fluid shows a similar picture. This pattern is typical but not specific to FIP. FIV can produce a narrow restricted peak that resembles a monoclonal one.
Healthy dogs usually have two beta-1 peaks, a normal feature of the canine curve. In dogs with leishmaniasis a broad beta peak is common, sometimes with an acute-phase rise; ehrlichiosis can give a polyclonal, restricted or even monoclonal-looking peak. A tall, narrow gamma spike is the picture a university laboratory shows for a dog with multiple myeloma.
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
- eClinPath (Cornell University College of Veterinary Medicine). Protein electrophoresis — chemistry / proteins.
- eClinPath (Cornell University College of Veterinary Medicine). Globulins — chemistry / proteins.
- Cornell University Animal Health Diagnostic Center. Total Protein Electrophoresis — testing guidelines, immunology.
- VCA Animal Hospitals. Serum Protein Electrophoresis.
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.