Globulin in Dogs: What High and Low Levels Mean

Normal globulin in dogs is 2.0–4.0 g/dL. It's the antibody and immune protein fraction of total protein, and it rises when the immune system is chronically activated — most commonly from tick-borne infections like Ehrlichia, chronic inflammatory disease, or, in serious cases, from a plasma cell tumor like multiple myeloma producing a monoclonal spike. Low globulin is less common but indicates gut protein loss or impaired immune production. The key to interpreting globulin is understanding whether the elevation is polyclonal (broad immune response) or monoclonal (single-clone neoplasia).

What Are Globulins?

Globulins are not a single protein — they are a collection of many different proteins grouped together because they share similar electrophoretic mobility. The main functional groups are:

• • Immunoglobulins (IgG, IgM, IgA, IgE) — antibodies produced by plasma cells. Elevated in infections, immune-mediated disease, and plasma cell tumors.
• • Acute-phase proteins (fibrinogen, C-reactive protein, haptoglobin) — rise rapidly with inflammation, infection, or tissue damage.
• • Complement proteins — part of the innate immune system; involved in bacterial killing and inflammation.
• • Transport proteins (transferrin, ceruloplasmin) — carry iron, copper, and other substances.
• • Clotting factors — most are produced by the liver and classified as globulins.

Globulin Levels: What the Numbers Mean

Causes of High Globulin in Dogs

Polyclonal Hyperglobulinemia — Chronic Infections

The most common cause of significantly high globulin in dogs is a persistent infection that keeps the immune system continuously activated. The immune system produces large amounts of antibodies (IgG, IgM, IgA) and acute-phase proteins over weeks to months — raising globulins broadly across multiple subclasses.

• • Ehrlichia canis — tick-borne (brown dog tick). Chronic phase drives globulins very high; total protein may exceed 10 g/dL. Classic finding: thrombocytopenia + high globulins in a dog from a tick-endemic area.
• • Bartonella henselae/vinsonii — tick and flea-borne. Causes chronic low-level infection with polyclonal response.
• • Brucella canis — reproductive tract infection; chronic granulomatous disease with persistent immune activation.
• • Leishmaniasis — sandfly-borne; endemic in Mediterranean Europe, Middle East, and some U.S. regions. Very high globulins are characteristic; can cause proteinuria and kidney disease simultaneously.
• • Systemic fungal infections — Blastomycosis, Histoplasmosis, Cryptococcosis, Coccidioidomycosis. Regional distribution; all cause polyclonal hyperglobulinemia.
• • Heartworm disease — chronic antigen exposure; moderate globulin elevation.

Polyclonal Hyperglobulinemia — Inflammatory Disease

• • Chronic hepatitis — immune activation from ongoing liver inflammation; globulins elevated alongside liver enzymes.
• • Immune-mediated diseases (IMHA, IMTP, systemic lupus erythematosus) — autoantibody production drives globulin elevation.
• • Chronic pyoderma or deep tissue infection — long-standing bacterial infection activates ongoing antibody response.

Monoclonal Hyperglobulinemia — Neoplasia

A single clone of malignant plasma cells or B lymphocytes produces one specific immunoglobulin in large quantities. Unlike polyclonal elevations (broad humoral response), monoclonal spikes are a red flag for neoplasia.

• • Multiple myeloma — malignant plasma cell cancer arising in bone marrow. Classic triad: monoclonal spike on SPEP, bone lytic lesions, Bence-Jones proteinuria. Hypercalcemia is common. Median survival with treatment: 1–2 years.
• • B-cell lymphoma — some cases secrete a monoclonal immunoglobulin, producing a spike on SPEP alongside lymphadenopathy.
• • Chronic lymphocytic leukemia (CLL) — may show oligoclonal or monoclonal banding; mature small lymphocytes in peripheral blood.

Causes of Low Globulin in Dogs

Low globulin (below 2.0 g/dL) is less common than high globulin and is usually seen alongside low albumin (pan-hypoproteinemia), pointing to a gut protein leak.

• • Protein-losing enteropathy (PLE) — the damaged intestinal wall leaks all protein non-selectively. PLE in dogs causes both albumin and globulin to fall proportionally; the A:G ratio stays relatively preserved. IBD, lymphangiectasia, and GI lymphoma are common underlying causes.
• • Failure of passive transfer — neonatal puppies who didn't receive sufficient colostrum lack maternal immunoglobulins. Very low IgG; high infection risk in the first weeks of life.
• • Primary immunodeficiency — rare genetic conditions (e.g., IgA deficiency, combined immunodeficiency in some breeds). Recurrent infections in young dogs.
• • Severe malnutrition or cachexia — prolonged inadequate protein intake depletes all protein fractions.

What Happens Next?

• • Calculate A:G ratio — helps contextualize whether albumin is appropriately related to globulin levels
• • Tick-borne disease panel (Ehrlichia, Anaplasma, Rickettsia, Bartonella) — first test for high globulins in tick-endemic areas
• • Serum protein electrophoresis (SPEP) — if globulin >5 g/dL or myeloma features present
• • Urine Bence-Jones protein — if myeloma suspected on SPEP
• • Bone marrow aspirate — if monoclonal spike confirmed
• • Leishmaniasis serology/PCR — in dogs with travel history or endemic exposure
• • Abdominal ultrasound + GI workup — if globulin is low alongside low albumin