Heart and Blood: Overview of Blood

The Chemistry and Composition of Dog Blood:

Canine blood is an alkaline fluid, which circulates throughout the entire body through blood vessels and capillaries. The blood pH of a healthy dog ranges 7.32 – 7.52. Blood is relatively viscous (not watery), although water is a major component.

Dog Blood Temperature

The temperature of dog blood varies, on the surface it is low, while deep in the viscera (internal organs of the body) it is relatively high. The hepatic portal vein contains blood with the highest temperature. Dog blood temperature ranges 34 – 40 Degrees Celsius (93.3 to 104 degrees Fahrenheit)  in different parts of the dog’s body.

Components of Canine Blood

Dog blood has two main parts, i.e. blood cellular content is suspended in fluid, with a part of the fluid called plasma. Blood cells are identified as, red blood cells (RBC - Erythrocytes), white blood cells (WBC – Leukocytes), and platelets (Thromobocytes), while the fluids of the blood i.e. plasma constitutes some 66% of whole blood volume.

Types of Blood Cells:

• Red Blood Cells (Erythrocytes); Red Blood cells or RBC make up 32% of whole blood. Under the microscope red blood cells can be identified as biconcave, which means they are circular shaped cells with no nucleus in them, as the nucleus usually disappears during the formation of the cell.

  Red blood cells or erythrocytes are a major cellular component of canine blood, and are similar to soft, flexible envelopes, which contain a red-pigmented protein called hemoglobin. Hemoglobin is red in color, and thus makes the color of blood appear so red. Hemoglobin is an important factor for the supply and excretion of oxygen and carbon dioxide respectively.

  Red blood cells usually are destroyed after an age of 3 – 4 months and are regenerated in the red bone marrow.

• White Blood Cells (Leukocytes); White blood cells are nucleated, larger then RBC and fewer in numbers as they circulate in the blood. In canine blood, the ratio of WBC to RBC stands at 1:700. A white blood cell may have two different types, i.e. granulocytes and agranulocytes. Granulocytes are further classified as neutrophils, eosinophils and basophils according to their morphology and staining capacity. On the other hand, agranulocytes have two types, i.e. monocytes and lymphocytes.

  White blood cells specialize in maintaining the immune status of the dog’s body by inhibiting and executing (killing) of foreign bodies which enter into circulation.

• Platelets; Platelets or thrombocytes are the smallest part of the cellular content of blood, and have the function of reducing blood loss in injury by forming a white clot when a dog is hemorrhaging (bleeding). Dog platelets not only save blood loss, but also protect the body against chances of any foreign material entering into the body.
• Plasma: Plasma is the fluid part of the blood in dogs, making up 66% of whole blood, with the cellular contents suspended in it. This not only contains the blood cells but also different enzymes, hormones and traces of different substances such as minerals and proteins, which are necessary to sustain body function. Dog blood plasma may also contain glucose, which is used for fulfilling the energy needs of a dog's body.

Blood also contains different enzymes and hormones, which controls and regulates functions of different systems.

Dog Blood Type:

Both in the wild and in domesticated dogs, thirteen different dog blood types  or groups have been identified, but out of them eight are important.

Clinically, only five of these blood types are used and practiced for different procedures as tests and canine blood transfusions etc. A dog blood type is dependent upon a specialized protein, in fact an antigen called “Dog Erythrocytes Antigen” or DEA that occurs on the surface of red blood cells of dog blood. DEA 1.0, 3.0, 4.0, 5.0 and 7.0 are clinically significant types of dog blood.

Dogs with blood group 1.0 are relatively more at risk of blood incompatibility or complications, such as hemolysis (the breakdown of blood cells which release hemoglobin), so dogs with this canine blood type are not considered good donors and/or recipients.

Dog Blood Tests and What the Results Indicate:

Dog Blood tests are a veterinarians way of gaining insight into the functioning of a dog's body and various canine blood disorders.  

Canine blood tests can be used to see how specific organs or groups of organs are functioning.  The canine blood  tests themselves are referred to as either a chemistry panel or biochemistry profile and are typically used to measure the following:

Complete Blood Count (CBC):

A veterinarian usually orders what is called a complete blood count (CBC).  This is a measurement of the number of cells in the blood including the red and  white cells plus the platelets.

General Findings of Dog Blood Tests:

 If the red blood count is low (called canine anemia), then the bone marrow isn't producing enough of the cells. This bone marrow problem is called hemolysis.  Other causes of anemia  include bleeding due to trauma or injury or a condition called polycythemia, which is a change in blood as a result of a dog being dehydrated.

Hemoglobin counts measure the amount of oxygen being carried by the blood.  It is a component of red blood cells.

The complete blood count also includes a measure of hemoglobin, which is the actual substance in the red blood cell that carries oxygen.

Tests also look at the different kinds of white blood cells.  These include:

• Neutrophils (PMNs): Produced in bone marrow and help dog's fight infection.  Lower levels could indicate bone marrow disease, viruses, if a dog is receiving chemotherapy treatment.  Increased levels are seen when a dog has an infection, is using the medication prednisone or cortisone type medications.
• Lymphocytes: Produced by the lymph nodes located in different locations in the body and fight infection such as viruses and bacterial diseases. Decreased levels are seen when a dog is suffering from diarrhea, is under stress, or due to medications such as cortisone.  Puppies will have higher levels during an infection.
• Monocytes: Produced in bone marrow. Higher levels are seen in dogs suffering form an infection.
• Eosinophils: Produced in bone marrow. Higher levels are associated with allergy and infections due to parasites such as worms or fleas.
• Basophils: Produced in bone marrow. Like eosinophils, higher levels are seen in dogs suffering from allergy or parasites.

Platelet levels are the clotting mechanism in blood.  Low levels are associated with a problem with the bone marrow, immune-mediated diseases (called IPT, IMT),  Thrombocytopenia is an immune-mediated dog blood disorder that describes a problem where a dogs own immune system attacks and destroys the platelets.

DIC (idsseminated intravacular coagulation) is another immune system disorder, where the clotting action of the blood is faster than the body can produce the needed platelets.  Symptoms of DIC include bruising, dog blood in the urine, and canine blood in the feces or stool.

Packed Cell Volume (PCV):

This test refers to the amount of red blood cells (RBC) in the blood.

Tests for Dog Liver Disease:

Albumin:

This is a test of the liver with lower levels indicating that  a dog is suffering from dehydration.  Albumin is a protein produced in the organ and is used to absorb water.  Lower levels indicate liver damage and  that the heart is pushing blood into the blood vessels with too much force causing leakage.  These leaks settle in different part of the body such as the abdomen or tissues.   Also seen with decreased Total protein levels indicating a compromised immune system.

Alkaline Phosphatase:

Higher levels of this blood component indicate diseases such as canine liver disease, higher levels of cortisol in the blood (medications such as prednisone will cause this to happen) or bone disease.

ALT

An enzyme that is produced in the liver.  If the liver isn't functioning properly, the ALT levels will increase in the blood.

Bile (bile acid test)

Bile breaks down fats in the body and are produced by the liver.  Levels indicate liver health and if the blood flowing into the liver is at normal levels.   This test is conducted after a fast and then again 2 hours after a dog resumes eating.

Bilirubin

This is produced in the liver from older RBCs.  Higher levels indicate canine liver disease, gallbladder problems or homolysis (destruction of red blood cells faster than normal). Symptoms include yellowish coloration on the body (called jaundice, icterus) including the inner areas of the ears, gums and eyes.

Tests for Dog Kidney Disease:

Elevated levels of BUN and Creatine are seen in dogs with kidney disease.

BUN (blood urea nitrogen)

In addition to the liver, the kidneys also affect the BUN level.  The BUN is actually waste disposed of by the liver as a byproduct of dietary proteins. The kidneys then help to remove it from the body.  Kidney disease that has progressed to the point where 75% of the kidney is no longer functioning will cause an increase in BUN levels.  Dehydration will also result in an increased BUN as dehydration deprives the kidneys of blood, less blood means less waste.

Creatinine

The muscles produce creatinine as waste.  The kidney remove it from the body.  Elevated creatinine levels can indicate kidney disease or dehydration. 

Phosphorus

Phosphorus originates in a dog's bones.  The hormone PTH controls these levels (also controls calcium). Elevated levels are seen when 75% or more of the kidney is no longer functioning.

Potassium

Elevated levels of potassium also indicate kidney failure, often due to anti-freeze poisoning in dogs.  Other causes include Addison's disease, ruptured bladder or an obstructed bladder.   Potassium levels can decline when a dog vomits, has diarrhea, lost through the urine or when not eating properly.

Tests for Heart Muscle Damage:

Creatinine kinase (CK) is elevated when there is heart muscle damage or other muscle damage.

Tests for Dog Pancreas Disease: 

Amylase

This is another enzyme focused on sugar  that is produced in the pancreas and intestines.  Higher levels indicate pancreatitis, or pancreatic cancer.  LIpase levels are also increased in cases of pancreatic problems in dogs.

Blood Sugar or Glucose Blood Test

Low levels of blood glucose can indicate pancreatic cancer.

Indicators of Canine Cancer:

High Calcium Levels

Indicators of Eclampsia, Thyroid Problems or Anti-freeze Poisoning:

Low Calcium Levels

Low calcium levels are seen immediately before a dog gives birth or when nursing. This condition, called eclampsia occurs with greater frequency in smaller breeds.  It could also  be an indication of a thyroid glandular problem such as the production of the hormone PTH, which controls calcium levels in the blood.

Dog Cholesterol

Blood tests are used in dogs to determine cholesterol levels.  Elevated levels can indicate Diabetes, Kidney Disease, hypothyroidsim and Cushing's Disease.  High cholesterol levels in dogs do not pose the same threat that they pose in human health.

Diabetes and Dog Blood Glucose

High Blood Glucose levels

Dogs with diabetes mellitus will be accompanied by elevated levels of dog blood glucose.  Urinalysis is used to test for diabetes as well, since glucose levels will also be elevated in the urine.

Low Dog Blood Glucose Levels

Lower blood glucose levels can indicate pancreatic cancer or an infection (called sepsis). Symptoms associated with this problem include seizures or depression.

Addison's Disease (hypoadrenocortiscium)

Low Levels of Sodium

In canine addison's disease could be indicated by low levels of blood sodium.

Dog Dehydration

Indicators of dog dehydration in blood tests include increased levels of:

• sodium 
• red blood cells (called polycythemia)
• albumin (how blood vessels attract water)
• Blood Urea Nitrogen (BUN)
• Creatinine
• Protein levels

Dog Blood Diseases:

The association of different diseases relative to canine blood may be of two different forms; some are directly related to the components of blood cells, while in other conditions, blood plays the role of a medium or source.

Leukemia, thrombocytopenia, hemolytic diseases, dog blood cancers such as lymphomas and sarcomas, vascular disorders and coagulation disorders are examples of common diseases associated directly with different cellular and fluid components of dog blood.

Diseases where dog blood acts as a medium are usually of an infectious or contagious type. Blood carries different microbial organisms which causes different generalized diseases. Parasites such as Rickettsia, flagellates and piroplasms can infest blood. Viruses’ can cause viremia, and bacteria leads to bacteremia causing not only generalized illness in dogs, but also causes toxicity in the dog's blood.

Monitoring is the base approach for treating dog blood diseases or disorders. When treating a canine blood disorder, progress and developments should be thoroughly monitored every 3 – 5 days during treatment.

Blood in Dog Urine

The presence of blood in dog urine could be an indication of an infection (bacterial, fungal), parasite, the presence or stones, poisoning or it could be due to trauma or a drug reaction.

The color of the urine and laboratory tests could indicate the underlying cause and indicate the required course of treatment.  Nutrition is often one of the cornerstones of treatment.

Dog Blood Donors

A canine blood donor is in high demand as dog blood transfusions are needed in a number of situations such as during surgery, trauma and for bleeding disorders.  Plasma and RBCs are the parts of blood needed most often.Before a dog can be a blood donor, they must pass a set of criteria including health, blood type, transfusion history and weight.  Dogs recover the blood weight in 24 hours and will take 2 to 3 weeks for the blood count to return to normal.

Canine High Blood Pressure

Canine high blood pressure is usually secondary in nature as it is caused by conditions such as kidney disease, diabetes mellitus or problems with the adrenal glands.  There is a form of high blood pressure that is only seen in hunting dogs that affects the lungs.  Treatment involves medications and addressing any underlying cause for the condition.  High blood pressure is measured with a cuff on placed on the forelimb.

Dog Blood in Stool

Blood in dog stool can have multiple causes including infection, injury, parasites such as worms, inflammation in the gastrointestinal system, ingestion of a sharp object of malignant tumors. 

Testing of the feces in the laboratory as well as a review of any clinical symptoms can help the veterinarian formulate a diagnosis and course of treatment.   Mild cases may benefit from home remedies such as the addition of garlic to the diet, and the substitution of homemade food instead of commercial food.

Dog Vomiting Blood

A dog throwing up blood can indicate a mild one time problem or something more severe.  The most common cause is a gastrointestinal issue which is usually accompanied by other signs such as bloody diarrhea or anorexia (loss of appetite).  A severe cause might be the growth of a tumor that is negatively affecting the gastrointestinal tract.Other causes include poison or swallowing a dental related item such as a tooth.A dog vomiting blood could be due to something as simple as a food intolerance.  Noe if there has been any change in a dog's diet to determine the source of the trigger.  

To determine the cause of a dog throwing up blood, a veterinarian will need to examine the content of the dog's vomit as well as a review of any other clinical signs or symptoms.