Understanding Pre-Surgical Blood Work : Why is it so important ?

Q: Are the pre-anesthetic tests really necessary?

A: We highly recommend these tests for three very important reasons:

1) We screen your pet for a variety of internal diseases and conditions that could cause surgical or anesthetic complications. We recommend blood work for the very same reasons our doctor would send you for blood work prior to a surgery… it is every bit as important for our four legged friend.

  • We evaluate kidney function: The kidneys act as a filter, removing waste and toxins from the body. If they're not functioning properly, there could be problems during surgery because your pet may not be able to filter out the anesthesia, complicating your pets recovery.
  • We evaluate liver function: The liver's function affects all other major organs. If there's a liver problem, it could impact other areas of the body.
  • We evaluate glucose levels: Glucose can be too high (diabetes) or too low (hypoglycemia). Either one can have a devastating impact on your pet during surgery. For puppies and kittens, we focus on hypoglycemia. They have very little fat reserve and are usually fasted pre- and post-surgery.
  • We identify if your pet has underlying conditions that may not be apparent during the physical exam.
    • If your pet's blood is not clotting properly, it can be crucial in any situation that could cause bleeding.
    • If your pet's ability to fight infection is impaired, she may get sick or have trouble recovering from surgery.
    • If your pet has trouble breathing, it can cause trouble during the surgery and during recovery.

2) We can tailor your pet's anesthetic, pain management and recovery protocols to her individual needs. For example, we evaluate electrolyte levels before surgery. If there is an imbalance, we can adjust her fluid therapy treatment to improve recovery and overall health.

3) These tests provide an important individual baseline for your pet's health. We can use these test results in the future to monitor her health, including kidney, liver, pancreas and glucose function. We can provide you with a copy of the results for your file, as well. These are very helpful when you travel or if you have to visit another clinic where they don't have your pet's health history.


Blood Test Definitions:


Complete Blood Count (CBC)

This is the most common blood test performed on pets and people. A CBC gives information on hydration status, anemia, infection, blood clotting ability and the ability of the immune system to respond. This test is essential for pets with fever, vomiting, diarrhea, weakness, pale gums or loss of appetite. If your pet needs surgery, a CBC can detect bleeding disorders or other unseen abnormalities.

HCT & RBC (hematocrit & red blood cell number) measures the percentage and absolute number of red blood cells to detect anemia and dehydration.

Hb, MCHC, MCH and MCV measures the oxygen-carrying pigment, size and shape of the red blood cells.

WBC (white blood cell count) measures the body's immune cells. Increase or decrease indicate certain diseases or infections.


Blood Chemistries

These common blood serum tests evaluate kidney and liver function and can help to diagnose a variety of diseases. They are important because they give us information about your pet that we cannot detect on a physical examination. They also allow us to have a baseline value that we can use as a comparison should something unforeseen arise that necessitates further blood tests. Lastly, should your pet need to be anesthetized for any reason it will give us more information about your pet that decreases his or her anesthetic risks.

ALB (albumin) is a serum protein that helps evaluate hydration, hemorrhage and intestinal, liver and kidney disease.

ALKP (alkaline phosphatase) elevations may indicate live damage, Cushing's disease, and active bone growth in young pets.

ALT (alanine aminotransferase) is a sensitive indicator of active liver damage but doesn't determine the cause.

AML (amylase) elevations show pancreatitis or kidney disease.

BUN/Urea (blood urea nitrogen) relates to kidney function. An increased blood level can be caused by kidney, liver, heart disease, urethral obstruction, shock and dehydration

Ca (calcium) deviations can indicate a variety of diseases. Tumors, hyperparathyroidism, kidney disease, and low albumin are just a few of the conditions that can alter serum calcium.

CHOL (cholesterol) is used to supplement diagnosis of hypothyroidism, liver disease. Cushing's disease and diabetes mellitus.

CREA (creatine) reveals kidney function. This test helps distinguish between kidney and non-kidney causes of an elevated BUN.

GGT (gamma glutamyl transferase) is an enzyme that indicates liver disease or corticosteroid excess.

GLOB (globulin) is a blood protein that often increases with chronic inflammation and certain disease states.

GLU (glucose) refers to the sugar levels in the blood. Elevated levels may indicate diabetes mellitus. Low levels can cause collapse, seizures or coma.

K (potassium) is an electrolyte lost through vomiting, diahrrhea, or excessive urination. Increased levels may indicate kidney failure. Addison's disease, dehydration, and urethral obstruction. High levels can lead to cardiac arrest.

LIP (lipase) is an enzyme that may indicate pancreatitis.

Na (sodium)is an electrolyte lost through vomiting, diarrhea, kidney disease and Addison's disease. This test also helps indicate hydration status.

PHOS (phosphorus) elevations are often associated with kidney disease, hyperthyroidism, and bleeding disorders.

TP (total protein) indicates hydration status and provides additional information about the liver, kidney and infectious diseases.

T4 (thyroxine) is a thyroid hormone. Decreased levels often signal hypothyroidism in dogs, while levels indicate hyperthyroidism in cats.