I'm thinking that if they want to re-check in a week, they probably just ran a standard pre-surgical blood panel (without a full liver panel...normally the pre-surgical full liver panel is done for older dogs). If I had to guess, I'd say it's likely that your dog had an elevated blood urea nitrogen (BUN) level. It's likely nothing serious or they wouldn't have you waiting a week.
Did you keep your dog from eating 12 hours before having the bloodwork? Sometimes high protein food and not fasting properly can cause the BUN reading to be high.
In a typical liver panel, they normally check quite a bit more. That normally includes:
ALP (Alkaline Phosphatase)
ALB (Albumin)
GGT (Gamma-glutamyl transpeptidase)
SGPT (Serum glutamate pyruvate transaminase
TP (Total Protein)
CHOL (Cholesterol)
GLOB (Globulin)
TBILI (Total Bilirubin)
I've got a senior dog who has blood taken all too often so I have lots of experience with the typical liver panel, complete blood count tests, and a host of other blood tests.
I wouldn't panic just yet. It sounds like you and your vet are doing the right thing.
