Abnormal Blood Work in Horses

Bloodwork is routinely done on a horse both for diagnostic and preventative reasons. Blood tests can help narrow the causes of symptoms such as fatigue or restlessness. They can also provide an early warning of problems that have not yet shown up in the horse's daily behavior. Those problems include liver or kidney damage as well as general infections. A typical equine blood panel can provide a large number of results, and here are the most common numbers.

  1. Liver Function: GGTP

    • Gamma glutamyltransferase is an enzyme involved with liver function. While GGTP levels can rise for a variety of reasons, it is a very useful measure because it only tracks liver function. If the results are higher than the normal range of 3-30 IU/liter during or after an endurance ride, a trip to the veterinarian should be scheduled immediately.

    Oxygen Transport Systems

    • A horse's pO2, pCO2, sO2 and Hb levels measure the amount of oxygen reaching its tissue. Oxygen absorption can be slowed or blocked by a number of infections. The numbers can also be impacted by dehydration or anemia. Normal levels can vary depending on the fitness of the horse and the amount of exertion it has undergone in the past week. Generally speaking, the normal ranges you might expect to see in a healthy horse are pO2 levels between 30-16 mmHg, and pCO2 levels of 50-96 mmHg; an Hb level of 10-18 and an sO2 level about 60.

    Glucose

    • Unlike most other animals, diabetes in horses is rare. So abnormally high insulin levels are likely due to factors such as dietary manipulation and/or an excess of adreneline, which takes place after a long workout. Low glucose levels are more of an issue, and might be the result of glycogen depletion. The average range for insulin horses is between 69 and 122 mg/dl.

    Muscle Enzymes

    • CPK, LDH, SGOT/AST are enzymes that help diagnose the presence of muscle injury or disease, its severity and progression. There is not a general "healthy" range for these enzymes. Instead, it's necessary to track the results of several rounds of testing and combine any changes with other factors such as fatigue, muscle soreness or other noticeable physical injuries.

    Hemoglobin

    • This test measures the amount of oxygen that can be carried in red blood cells. Too little oxygen and the horse won't get the oxygen the muscles need to work at peak performance. Too much oxygen and the blood begins to thicken and the flow of blood is restricted. A normal range would be 14.5 to 15.5 gm/100 ml of blood. Levels below 12.5 and above 16.0 will affect performance.