Can any internal medicine doctor interpret most blood tests or is it better to see a specialist such as for blood tests for lupus or blood disorders?

Depends: A good internist will be able to interpret most routine and many non-routine lab tests. A good doctor will know his limitations and when he or she should refer to a sub-specialist.

Start with PCP: Yes, any general internist can interpret routine blood work including for auto immune issues like lupus, but there may be a benefit of having a specialist like a rheumatologist (arthritis doctor) help if further testing and detailed management of such disorders if needed. Best regards.