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Preparing Your Pet for a Blood Test

Why is it important to prepare my pet for blood collection?

Having your pet properly prepared for a blood test helps to ensure that the results are as accurate and reliable as possible. Sometimes test results are abnormal only because the pet was not properly prepared. If your veterinarian suspects the results are unreliable, you may need to have the blood tests repeated.

Is preparation the same for all blood tests?

No. Blood tests can be grouped as routine testsand special tests. Preparation for these two types of tests is slightly different.  

Routine testing provides an overview of an animal’s health and is done in both healthy pets (See articles on “Wellness Testing”) and sick pets (See articles on Complete Blood Count and Biochemistry Profile). Any visit to the veterinarian could include a routine blood test. By having your pet properly prepared for each visit, you may save valuable time and money by reducing the need for repeat testing.

"By having your pet properly
prepared for each visit you may save
valuable time and money.”

Special tests are done to investigate or monitor a specific problem. For example, the veterinarian might want to monitor the blood sugar level in a diabetic pet, or to test for drug levels in pet on medication. Proper preparation for “special” tests is essential for accurate results.

How do I prepare my pet for routine blood collection?

Things you can do to prepare your pet for a routine visit to the veterinarian include:

1. Gentle fasting: If possible, do not feed your pet for about 6 hours before your appointment. Fasting helps to clear the blood of lipemia, fat droplets that appear after eating. Lipemia can interfere with some blood tests and make the results difficult to interpret.

2. Keep water available: This is especially important in warm weather. Even mild dehydration may change the test results, so be sure your pet has access to water before your visit to the veterinarian.

3. Avoid exercise and active play just prior to your visit: Physical activity can cause changes in test results, so exercise and active play should be avoided.

4.  Minimize stress: This may be difficult if your pet is nervous or frightened, but some suggestions include:

  • Cats: Bring your cat in a cat carrier. This helps your pet feel more secure and eliminates the risk of escape.
  • Handle your pet calmly and quietly - talking in a soothing voice may help to distract your pet and reduce anxiety.
  • If the waiting room is crowded, you may wish to let your pet wait in the car (weather permitting) to reduce excitement.
  • If your pet is highly excitable and the veterinarian is concerned this may affect blood test results, your appointment may be booked at a separate time when the clinic is quieter. This may reduce the stress associated with taking a blood sample.

How do I prepare my pet for a "special" blood test?

The preparation for a special blood test depends on the test.

For example, you may be asked to:

  • Fast your pet strictly for 12 hours or more.
  • Give medication at a specific time before your visit – e.g. if you are asked to give medication 4 to 6 hours before the appointment, you may need to change what time you give your pet his regular dose.
  • Withhold medication before the blood sample is taken - e.g. Follow the instruction “Do not give medication after 7:00 a.m. on the day of your next visit” even if it means delaying or skipping a dose.

...and so on.

Your veterinarian will give you specific instructions before your appointment (See “Special preparation for your pet's next visit” below.) It is important that you follow these instructions exactly to ensure accurate test results.

Special preparation for your pet's next visit

Date of next appointment: ­­­­­­­­­­­­­­_________________________________

Pet's Name: ____________________________________________

Test to be performed: ____________________________________

 

Please follow these steps to prepare for your next visit to the veterinarian:

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© Copyright 2025 LifeLearn Inc. Used and/or modified with permission under license. This content written by LifeLearn Animal Health (LifeLearn Inc.) is licensed to this practice for the personal use of our clients. Any copying, printing or further distribution is prohibited without the express written consent of LifeLearn. This content does not contain all available information for any referenced medications and has not been reviewed by the FDA Center for Veterinary Medicine, or Health Canada Veterinary Drugs Directorate. This content may help answer commonly asked questions, but is not a substitute for medical advice, or a proper consultation and/or clinical examination of your pet by a veterinarian. Please contact your veterinarian if you have any questions or concerns about your pet’s health. Last updated on Jul 8, 2016.