Why can’t I feed my dog before a blood test?

A: Recently, I had to take my dog to the vets to have a blood sample taken for thyroid testing. My vet told me not to feed my dog beforehand. Any good reason for this?

Q: Quite simply, feeding immediately before blood is taken can result in a lipaemic sample. When the blood is centrifuged to separate the serum from the cells, the liquid layer ends up thick and white with fat, making it impossible to test. To be honest, it would put you off ever eating a fish supper if you saw how gloopy your blood became afterwards.