Total protein in cats and dogs
Total protein is the sum of all proteins in the liquid part of the blood — mostly albumin and globulins. It is a first, rough look: it responds to water balance, inflammation, protein loss and liver function. Its meaning becomes clear only when albumin and globulin are read next to it.
What it shows
Albumin makes up about 35–50% of plasma protein by weight; all the other proteins are grouped as globulins — antibodies, acute-phase proteins of inflammation, transport and clotting proteins (eClinPath). Plasma also contains fibrinogen, which is used up when blood clots, so total protein in plasma reads somewhat higher than in serum.
It is measured in two ways. Chemistry analyzers use a colour reaction (the biuret method). In clinics it is often estimated with a refractometer, which measures all dissolved substances, so glucose, urea or infused colloids (fluids given through a drip) can push the reading up; in dogs and cats refractometer values are usually higher than analyzer values (eClinPath).
Higher than reference — what it may be a sign of
- Dehydration: less water, the same amount of protein (Merck). Albumin and globulins then rise together, and the A/G ratio stays unchanged (eClinPath).
- More globulins: chronic inflammation and infection, or a tumour of plasma cells or B cells that produces a single antibody (paraproteinemia), such as multiple myeloma.
- Artefacts: severe lipemia raises results by both methods; severe hemolysis raises the analyzer result; a poorly capped tube that has lost water concentrates the sample.
Lower than reference
A low total protein usually means that both albumin and globulins are low (panhypoproteinemia). The main causes are blood loss, internal or external, and protein-losing enteropathy, when protein leaks through a diseased gut (eClinPath). Other possibilities listed by Merck: protein loss through the kidneys, burns, dietary protein deficiency or poor absorption, and overhydration, for example with excess drip fluids. In young animals globulins are naturally lower.
Look at together with
- Albumin and globulin — show which part has changed. Globulin is calculated as total protein minus albumin.
- A/G ratio — high total protein with a normal ratio suggests dehydration; with a low ratio, excess globulins (eClinPath).
- UPC (urine protein : creatinine) — checks for protein loss through the kidneys.
- Cholesterol — often low with protein loss through the gut and high with protein loss through the kidneys (nephrotic syndrome), a clue to where protein is going (Merck).
Units and conversion
European and Russian labs report g/L (г/л), North American labs g/dL (г/дл). One g/dL equals 10 g/L, so 6.5 g/dL is 65 g/L. The same factor applies to albumin and globulin. A refractometer result and an analyzer result are not interchangeable even in the same units, and different refractometers may not agree with each other, so trends are followed with one method.
Reference range
The reference range is on your lab’s form. It helps to know what was measured: serum or plasma, analyzer or refractometer — plasma and refractometer values usually run higher. Total protein in range does not guarantee that albumin and globulin are in range: one can fall while the other rises, leaving the sum unchanged. That is why a vet reads albumin, globulin and their ratio rather than the total alone.
Cats and dogs
In cats a high total protein driven by globulins is one of the routine findings that can support a suspicion of feline infectious peritonitis (FIP), but high globulins also occur with chronic infection, lymphoma and multiple myeloma (Merck). Kittens have naturally lower albumin up to about 2 weeks of age and lower globulins up to about 8 weeks (eClinPath).
In dogs high globulins, and with them total protein, can come with chronic infections such as ehrlichiosis or heartworm disease (eClinPath). A low total protein is typical of protein loss through the gut and of blood loss. Puppies have lower globulins up to about 8 weeks, and their albumin tends to be lower up to 6–20 weeks, although it may still fall within adult ranges.
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) — Total protein
- eClinPath (Cornell University) — Albumin
- eClinPath (Cornell University) — Globulins
- eClinPath (Cornell University) — Albumin to globulin ratio
- Clinical Biochemistry. Merck Veterinary Manual
- Feline Infectious Peritonitis. Merck Veterinary Manual
- Miscellaneous Serum Biochemical Measures in Hepatic Disease in Small Animals. Merck Veterinary Manual
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.