Before your pet undergoes an anaesthetic we would always recommend a pre anaesthetic blood test to help determine the health of your pet, in young animals as well as older patients. We clip a small patch of hair either from the neck or front leg and take a small sample, usually 1-2mls of blood for analysis. What we test:
Liver function: The liver is an important organ involved with metabolising anaesthetic drugs. If the liver function is compromised it can interfere with your pet’s recovery following their anaesthetic. It can also determine which drugs the surgeon may choose to use. Elevated liver enzymes can be the result of cancers, infections, hormonal imbalances, circulatory problems, inflammatory conditions and congenital conditions. Young animals showing no clinical signs can be born with a birth defect, early detection can mean that the problem could be rectified before it results in any long term health problems.
Kidney function: The kidney is another organ important in the filtering of anaesthetic drugs from the body. The kidney is sensitive to any blood pressure changes that are the result of dehydration and anaesthetics. If the kidney enzymes are elevated this indicates that the kidney waste level is high, we can support the kidneys with fluid therapy throughout the procedure or even delay the surgery.
Blood glucose level: Elevated blood glucose levels indicates diabetes. Juvenile diabetes is rare but can have detrimental effects if not detected early on. Young animals are less able to control their blood sugar levels, usually an overnight fast will not cause a problems but very young or small animals may need more support. It can be a useful measure in older patients.
Protein levels: Protein is vital for healing post surgery so it is important that these levels are not depleted. High levels of protein can be indicative of serious inflammatory disease or cancer.
Electrolyte levels: These include sodium, potassium and chloride; these tissue salts are used in normal muscle function (including the heart). Changes in the levels of these salts can cause upset tummies, dehydration, hormonal abnormalities and kidney disease.
Red blood cell count: Red blood cells transport oxygen to the cells around the body. Too many red blood cells can indicate dehydration or lung disease. Too few blood cells (anaemia) could mean that the surgery be delayed, particularly in cases where large blood loss is expected. In some instances a blood transfusion may be required.
White blood cell count: Increased levels of white blood cells indicates infection within the body.
If an abnormality is detected the anaesthetic protocol may need to be adjusted or the surgery postponed until the abnormality has been addressed.
If nothing is wrong, this is great news! You have not wasted your money; you have been given good news and have a better understanding of what is normal for your pet. For future blood tests we will have a record of a good baseline of what is normal for your pet.
We would always recommend a blood test for every anaesthetic, even if your pet only had one a year or so ago. Pets age much quicker than humans, so a year for us can be as much as 7 years for them! Imagine having a test at 70 and then not again until 77, many changes can occur in that time.