01 = General practice
02 = General surgery
03 = Allergy/immunology
04 = Otolaryngology
05 = Anesthesiology
06 = Cardiology
07 = Dermatology
08 = Family practice
09 = Interventional Pain Management (IPM)
10 = Gastroenterology
11 = Internal medicine
12 = Osteopathic manipulative therapy
13 = Neurology
14 = Neurosurgery
15 = Speech / language pathology
16 = Obstetrics/gynecology
17 = Hospice and Palliative Care
18 = Ophthalmology
19 = Oral surgery (dentists only)
20 = Orthopedic surgery
22 = Pathology
24 = Plastic and reconstructive surgery
25 = Physical medicine and rehabilitation
26 = Psychiatry
27 = General Psychiatry
28 = Colorectal surgery (formerly proctology)
29 = Pulmonary disease
33 = Thoracic surgery
34 = Urology
35 = Chiropractic
36 = Nuclear medicine
37 = Pediatric medicine
38 = Geriatric medicine
39 = Nephrology
40 = Hand surgery
41 = Optometrist
42 = Certified nurse midwife
43 = Certified Registered Nurse Anesthetist (CRNA)
44 = Infectious disease
46 = Endocrinology
48 = Podiatry
50 = Nurse practitioner
62 = Psychologist (billing independently)
64 = Audiologist (billing independently)
65 = Physical therapist (private practice)
66 = Rheumatology
67 = Occupational therapist (private practice)
68 = Clinical psychologist
72 = Pain Management
76 = Peripheral vascular disease
77 = Vascular surgery
78 = Cardiac surgery
79 = Addiction medicine
80 = Licensed clinical social worker
81 = Critical care (intensivists)
82 = Hematology
83 = Hematology/oncology
84 = Preventive medicine
85 = Maxillofacial surgery
86 = Neuropsychiatry
89 = Certified clinical nurse specialist
90 = Medical oncology
91 = Surgical oncology
92 = Radiation oncology
93 = Emergency medicine
94 = Interventional radiology
97 = Physician assistant
98 = Gynecologist/oncologist
99 = Unknown physician specialty