| Nurse practitioner | 469 |
| Physician assistant | 364 |
| Physical therapist (private practice) | 323 |
| Family practice | 265 |
| Chiropractic | 134 |
| Emergency medicine | 125 |
| Certified Registered Nurse Anesthetist (CRNA) | 110 |
| Optometrist | 93 |
| Internal medicine | 92 |
| Mental Health Counselors | 92 |
| Licensed clinical social worker | 81 |
| Anesthesiology | 77 |
| Psychiatry | 61 |
| Obstetrics/gynecology | 59 |
| General surgery | 53 |
| Orthopedic surgery | 48 |
| Diagnostic Radiology | 48 |
| Hospitalist | 43 |
| Occupational therapist (private practice) | 40 |
| Clinical psychologist | 34 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 31 |
| Certified nurse midwife | 23 |
| Ophthalmology | 21 |
| Neurology | 21 |
| Mass Immunization Roster Billers | 20 |
| Otolaryngology | 20 |
| Podiatry | 20 |
| Cardiology | 19 |
| Audiologist (billing independently) | 17 |
| Speech / language pathology | 16 |
| Registered Dietician/Nutrition Professional | 16 |
| Urology | 15 |
| Pathology | 14 |
| Ambulatory Surgical Center | 14 |
| Osteopathic manipulative therapy | 13 |
| Dermatology | 13 |
| Gastroenterology | 12 |
| Neurosurgery | 11 |
| Physical medicine and rehabilitation | 10 |
| Radiation oncology | 9 |
| Hematology/oncology | 9 |
| General practice | 8 |
| Critical care (intensivists) | 8 |
| Interventional Cardiology | 8 |
| Nephrology | 8 |
| Pediatric medicine | 8 |
| Independent Diagnostic Testing Facility (IDTF) | 8 |
| Allergy/immunology | 7 |
| Rheumatology | 7 |
| Clinical Laboratory (Billing Independently) | 7 |
| Plastic and reconstructive surgery | 6 |
| Infectious disease | 5 |
| Pulmonary disease | 5 |
| Oral surgery (dentists only) | 5 |
| Hospice and Palliative Care | 5 |
| Medical oncology | 5 |
| Centralized Flu | 5 |
| Pain Management | 5 |
| Interventional Pain Management (IPM) | 4 |
| Marriage and Family Therapist | 4 |
| Thoracic surgery | 4 |
| Vascular surgery | 4 |
| Endocrinology | 4 |
| Cardiac Electrophysiology | 4 |
| Addiction medicine | 3 |
| Cardiac surgery | 2 |
| Surgical oncology | 2 |
| Opioid Treatment Program | 2 |
| Sleep Medicine | 2 |
| Gynecologist/oncologist | 2 |
| Maxillofacial surgery | 2 |
| Pharmacy | 2 |
| Colorectal surgery (formerly proctology) | 2 |
| Interventional radiology | 1 |
| Geriatric medicine | 1 |
| Hand surgery | 1 |
| Radiation Therapy Centers | 1 |
| Mammography Screening Center | 1 |
| Neuropsychiatry | 1 |
| Psychologist (billing independently) | 1 |
| Sports Medicine | 1 |
| Peripheral vascular disease | 1 |