Before your pet has an anaesthetic your veterinary surgeon may discuss with you pre-anaesthetic blood tests, amongst many important considerations. All of the information provided to you is vital to ensure you are made aware of all of the risks and benefits to your pet associated with anaesthesia and surgery.
What is the aim of pre-anaesthetic blood tests?
The aim of performing pre-anaesthetic blood tests is to aid in detecting something that a full examination performed by your veterinary surgeon may not find. It is also a way of checking certain aspects of your pet’s health and may help in the future when looking at changes over time if your pet becomes ill.
What happens to my pet before they have an anaesthetic?
Before an anaesthetic your vet will fully examine your pet
- Your veterinary surgeon will fully examine your pet as they would do in the consultation room
- Particular focus will be made to assessing the heart and lungs, which your veterinary surgeon will listen to using a stethoscope
- Any abnormalities detected during the general examination may lead your veterinary surgeon to advise additional tests, which may or may not include blood tests, xrays and ultrasound
- In the majority of cases where your pet is healthy and requires anaesthesia for a non-urgent procedure, nothing will be found during the clinical examination
- Pre-anaesthetic blood testing may be performed on the morning your pet is admitted, or prior to this if it is a non-urgent procedure
What does pre-anaesthetic blood testing look for?
- Illness or certain disease not detectable on routine examination of your pet. Organs such as the kidney and liver are routinely looked at using blood tests, as some changes will not always be detectable on general examination of your pet
- Presence of low red blood cell count (anaemia)
- Presence of cells suggesting infection or inflammatory disease (high white blood cell count)
- Evidence of dehydration (high red blood cell count and high total protein levels)
What information may pre-anaesthetic blood testing NOT give my veterinary surgeon?
- The cause of the body organ disease or dysfunction may not always be identified and further testing may be required if an abnormal result is detected
- Not all organs can be routinely tested for. Certain organ function tests require blood sample to be sent to an external laboratory and therefore need to be taken prior to any planned anaesthetic
What questions should I discuss with my veterinary surgeon regarding pre-anaesthetic blood testing?
- In which pets they recommend blood testing
- How the results of the blood testing will either change or impact on the management of your pet’s anaesthetic
- What will happen if the results are abnormal? For example would they still recommend an anaesthetic or would they recommend further tests prior to anaesthesia
When should my pet have their blood test?
Although blood testing may be performed by your veterinary surgeon, in the majority of cases this does not provide any time to correct or investigate any problems for a planned procedure. In an emergency or urgent situation then blood testing will, of course be performed in this manner.
Blood testing prior to your pet being admitted for their anaesthetic will allow for any further testing required to be performed and prevent any delay on the day itself. In most cases, blood testing is best performed with your pet starved to give the most accurate results.
Blood samples are collected for pre-anaesthetic blood tests
How will my pet have their blood test performed?
Blood will be collected from a blood vessel, most commonly the jugular vein in the neck, with your pet held by a veterinary nurse. The sampling is performed in exactly the same way as a blood sample would be taken from yourself.
What evidence do we have when considering pre-anaesthetic blood tests?
Several studies have been performed in dogs to look at the benefits of pre-anaesthetic blood testing. These studies have helped to determine when the results may lead to a change in the management of your pet’s anaesthetic and therefore offer a benefit to your pet’s health. Importantly, even with these published studies the decision as to whether to perform any blood testing should be one you consider carefully with your veterinary surgeon.
The studies performed to date have shown that routine pre-anaesthetic blood testing does not impact on anaesthetic management in a healthy pet, undergoing a planned, routine procedure. It is important to note that when your pet is unwell or requires a particularly difficult or invasive procedure, blood testing prior to an anaesthetic will most likely benefit your pet’s treatment and allow your veterinary surgeon to plan effectively and safely. Only in dogs over the age of 8 years did blood testing help to detect disease that was not evident on clinical examination. There will always be cases though, where blood testing may detect something not found on full examination of your pet.
Recommendations on blood tests before anaesthesia
- All dogs over 8 years old are recommended to have blood testing prior to an anaesthetic. Although there are no similar studies in cats, blood testing should be considered when they over 8-10 years old
- If your pet is unwell and presents as an emergency to your veterinary surgeon, blood testing is recommended
- If your veterinary surgeon detects an abnormality on their examination of your pet, blood testing is recommended
- If you have any concerns regarding your pet’s health then you should discuss the benefits of pre-anaesthetic blood testing with your veterinary surgeon