Blood Disorders in Dogs

Types of Blood Disorders

For the warning sign many owners notice first, see pale gums in dogs.

Von Willebrand Disease

Von Willebrand disease (vWD) means a dog has too little, or abnormal, von Willebrand factor, a protein platelets need to stick to damaged vessels. Platelet counts are normal.^3,7

vWD has been found in nearly all breeds, and German Shepherds, Golden Retrievers, Miniature Schnauzers and Basset Hounds are among others listed.¹ Signs include bleeding gums (for example, while teething), nosebleeds, easy bruising and heavy bleeding after spaying, neutering or other surgery. Some dogs never show signs.³ A DNA test identifies dogs at risk and carriers, and a blood test of von Willebrand factor levels shows how affected a dog is.³ Before surgery, your vet may give a medicine that boosts von Willebrand factor (not for type 3) or plasma products, and NSAID pain relievers are avoided.^3,1 There is no cure, but many dogs live a normal lifespan with care.³

Hemophilia

Hemophilia A (low clotting factor VIII) and the less common hemophilia B (low factor IX) are inherited clotting factor disorders. Male dogs show signs, while females are usually carriers.¹ Dogs with very low factor levels bleed often, while others bleed mainly after injury or surgery. Treatment for bleeding is plasma or blood products.^1,6

Rat Poison and Other Clotting Problems

Anticoagulant rat and mouse poisons stop the liver from making active clotting factors. Bleeding usually starts 3 to 7 days after the bait is eaten, so a dog can look fine at first.¹¹ Signs include tiredness, nosebleeds, bruising, pale gums, coughing or breathing trouble from bleeding in the chest, and blood in vomit or stool.¹¹ Vets test clotting time (PT) and treat with a vitamin K-class antidote, usually for several weeks, plus plasma or blood for active bleeding.^11,1 See poisoning in dogs. Severe liver disease can also lower clotting factors.¹

DIC (Disseminated Intravascular Coagulation)

DIC is a clotting crisis that is always triggered by another serious problem, such as severe infection, parvovirus, bloat, pancreatitis, heatstroke, trauma, snake bites, IMHA or cancer.^15,22 Tiny clots form throughout the body and use up platelets and clotting factors, so the dog may later bleed.¹⁵ Treating the cause is the only approach shown to help, with plasma and platelets for active bleeding.¹⁵ It is often fatal, and earlier diagnosis improves survival.¹

Too Many Red Cells (Polycythemia)

A high red cell count is usually caused by dehydration, or briefly by excitement, and returns to normal with fluids.¹⁸ A true increase can come from low oxygen due to lung or heart disease, from kidney tumors, or from a rare marrow disorder called polycythemia vera.¹⁸ Signs usually don't appear until the PCV is above about 60%. They include red gums, nosebleeds, wobbliness, seizures and blindness, because the blood is too thick.¹⁸ Greyhounds and other sighthounds normally have higher red cell counts.^18,16

White Blood Cell Changes

High white cell counts usually mean infection, inflammation or stress, or steroid medicines. Very high counts can point to a walled-off infection such as pyometra, or to leukemia.²¹ Low white cell counts can follow overwhelming infection, parvovirus, some medicines or marrow disease.²¹ Not every high count is cancer. For example, about 70% of English Bulldogs with high B-cell counts had a harmless condition in one study.^23,8 See leukemia in dogs.

Dog Blood Types and Transfusions

Dogs have more than a dozen blood types, called dog erythrocyte antigens (DEA). DEA 1 matters most for transfusions.^5,13,6 Roughly half of dogs are DEA 1-positive, although figures range from about 40% (Merck Veterinary Manual) to 70% to 75% (a report from France) by study and region. Most Greyhounds are negative.^5,24,16

DEA 1-negative dogs are often called universal donors, because their blood can be given to most dogs in an emergency, though previously transfused dogs still need a crossmatch.^25,13 Some Dalmatians lack a common blood type (Dal) and may need donors from their own breed.^26,6 The most common transfusion reaction is a fever.⁶

Can my dog be a blood donor?

Many hospitals and blood banks welcome donors. Typical requirements are a healthy, good-natured dog aged about 1 to 7, weighing over 50 pounds, vaccinated and on heartworm prevention, and never transfused.^25,27,6 Donors are screened with blood type, infectious disease and blood tests, and some programs give donors free yearly bloodwork.²⁷

Tests for Bleeding and Clotting Disorders

• Platelet count with a blood smear checks for low platelets and rules out clumping.²⁸
• Buccal mucosal bleeding time, a tiny standard cut inside the lip, tests platelet function and is normally under 4 minutes.²⁸
• PT and aPTT test how quickly clotting factors work. PT rises first with rat poison.^28,11
• Von Willebrand factor level and DNA tests are used for vWD.^3,28
• Fibrinogen, D-dimer and clot-strength tests are used for DIC and clotting risk.^28,15

See blood tests for dogs for routine values.

Frequently Asked Questions

What is the most common blood disorder in dogs?

Acquired problems, such as anemia from blood loss or IMHA, low platelets and rat poison, are more common than inherited ones. Von Willebrand disease is the most common inherited bleeding disorder.

What are the signs of a bleeding disorder in dogs?

Pinpoint spots, bruises, nosebleeds and bleeding gums suggest a platelet problem. Deep bruises, swollen joints and bleeding into the chest or belly suggest a clotting factor problem.

How many blood types do dogs have?

More than a dozen. DEA 1 is the most important for transfusions.

Which dogs are universal blood donors?

DEA 1-negative dogs, such as most Greyhounds, are often called universal donors.

Can von Willebrand disease be cured?

No, but many dogs with vWD live a normal lifespan with care, including precautions before surgery.