Naturopaths can order any and all lab tests, from blood work to pap smears, ultrasounds, x-rays, and MRI's.
If you've had blood work done in the past 6 months, the results can be helpful -- so brings those if you have them to your appointment.
I do not order lots of lab work. I try to order only necessary labs that are going to better define what imbalance we're working with AND only if I think that information will affect treatment options. I work hard to treat people not numbers and anomalies! The goal is always to listen to what your body is saying and encourage it to do it's healing work better.
In consultation with you, you might also choose some less conventional tests that are available. Computerized regulation thermography scanning, ALCAT food allergy blood tests, and saliva tests for adrenal stress are three of the more common examples.