Before Pet Bloodwork, Confirm the Food and Water Instructions
PARTNER Editorial TeamAsk the clinic for preparation instructions for the exact blood test being performed. Do not assume that every blood draw needs the same fast, or copy the food-and-water rules from an earlier surgery appointment.
VCA’s blood-test preparation guide distinguishes routine testing from tests with specific timing requirements. A recent meal can produce fat droplets in blood, called lipemia, that interfere with some results. The Cornell diagnostic laboratory likewise notes that fasting, when practical, helps reduce lipemia. Neither point gives every patient the same home instructions.
Get four answers before the appointment
| Ask about | Write down |
|---|---|
| Food | Whether fasting is required and the exact start time |
| Water | Whether normal access should continue |
| Medicines and supplements | Which doses to give, and when |
| The appointment | Whether sample timing depends on a meal or dose |
Describe the pet’s age, known conditions and current medicines when asking. A diabetic animal’s preparation cannot safely be improvised from a general fasting article. Do not withhold insulin, another medicine or essential food unless the treating team has instructed you to do so.
A tiny reward still belongs in the history
Tell everyone who feeds the pet what the clinic requested. Include training rewards, food used to hide a tablet and access to another animal’s bowl. The point is not to guess which small snack “doesn’t count”; it is to prevent the clinic from interpreting the sample with an incomplete history.
If the pet eats unexpectedly, note the food, approximate amount and time. Call or tell the team on arrival. Let them decide whether to proceed, reinterpret the preparation or change the appointment. Do not hide the snack, induce vomiting or extend the fast yourself to compensate.
Make the morning easier without changing the instructions
Pack the medicine list and any previous test-specific directions the night before. Have a separate note of when the last meal and dose were actually given. If the appointment moves, ask whether that changes the plan rather than automatically adding more fasting hours.
Arrange calm transport and a secure carrier or leash. If you usually use food during travel, ask what alternative handling or reward plan fits this visit. Preparation should help the team obtain an interpretable sample while respecting the individual pet’s needs.
Confirm when the normal routine can resume
Before leaving, ask when to offer the next meal and whether any medicine timing changed. A blood draw does not automatically mean anesthesia, and anesthesia instructions do not automatically apply to bloodwork. Our surgery preparation article covers that separate situation.
Keep the resulting instructions with the appointment record. For the next test, confirm them again: a different clinical question may require different preparation even when the clinic and pet are the same.
Written by PARTNER Editorial Team for general education. Your veterinary team can advise on your pet’s individual health and feeding needs.