Depends on who you are being diagnosed by i.e., an Internist, PCP, GI or Hematologist. All of these doctors could prescribe what you need. Some will diagnose and send you back to your PCP for a follow up with doctor notes regarding your condition for treatment. Others will want you to see a Hematologist.
If I had PA I would see a Hematologist for blood and GI for diagnostic and blood testing. PA is treated the same as a B-12 deficiency. In fact some docs won't test for PA because it is treated the same as B-12 and they don't feel the testing is worthwhile. FLFLOWERGIRL