| Nurse practitioner | 1,411 |
| Physician assistant | 1,119 |
| Physical therapist (private practice) | 689 |
| Family practice | 613 |
| Licensed clinical social worker | 422 |
| Anesthesiology | 342 |
| Emergency medicine | 324 |
| Internal medicine | 293 |
| Diagnostic Radiology | 199 |
| Chiropractic | 188 |
| Mass Immunization Roster Billers | 186 |
| Optometrist | 184 |
| Certified Registered Nurse Anesthetist (CRNA) | 178 |
| Obstetrics/gynecology | 174 |
| Orthopedic surgery | 151 |
| Hospitalist | 139 |
| Clinical psychologist | 136 |
| Mental Health Counselors | 136 |
| Psychiatry | 122 |
| Ophthalmology | 114 |
| General surgery | 109 |
| Podiatry | 108 |
| Dermatology | 104 |
| Neurology | 97 |
| Physical medicine and rehabilitation | 83 |
| Pathology | 82 |
| Occupational therapist (private practice) | 78 |
| Pediatric medicine | 76 |
| Otolaryngology | 71 |
| Cardiology | 70 |
| Gastroenterology | 67 |
| Certified nurse midwife | 64 |
| Audiologist (billing independently) | 61 |
| Marriage and Family Therapist | 61 |
| Hematology/oncology | 56 |
| Pulmonary disease | 51 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 50 |
| Urology | 49 |
| Ambulatory Surgical Center | 41 |
| Speech / language pathology | 41 |
| Nephrology | 35 |
| Pain Management | 31 |
| Plastic and reconstructive surgery | 30 |
| Centralized Flu | 30 |
| Infectious disease | 30 |
| Sports Medicine | 29 |
| Medical oncology | 29 |
| Neurosurgery | 28 |
| Rheumatology | 27 |
| Registered Dietician/Nutrition Professional | 26 |
| Radiation oncology | 25 |
| Pharmacy | 23 |
| Critical care (intensivists) | 22 |
| Allergy/immunology | 20 |
| Endocrinology | 19 |
| Interventional Cardiology | 18 |
| Vascular surgery | 17 |
| Thoracic surgery | 13 |
| Interventional radiology | 12 |
| Hand surgery | 12 |
| Independent Diagnostic Testing Facility (IDTF) | 11 |
| Cardiac Electrophysiology | 10 |
| Oral surgery (dentists only) | 10 |
| Hospice and Palliative Care | 9 |
| Sleep Medicine | 9 |
| Clinical Laboratory (Billing Independently) | 9 |
| Geriatric medicine | 8 |
| Opioid Treatment Program | 8 |
| Colorectal surgery (formerly proctology) | 8 |
| General practice | 7 |
| Neuropsychiatry | 7 |
| Hematology | 6 |
| Public Health or Welfare Agencies (Federal, State, and local) | 6 |
| Surgical oncology | 6 |
| Interventional Pain Management (IPM) | 6 |
| Unknown Provider | 5 |
| Addiction medicine | 4 |
| Cardiac surgery | 4 |
| Gynecologist/oncologist | 4 |
| Undersea and Hyperbaric Medicine | 4 |
| Anesthesiologist Assistant | 3 |
| Osteopathic manipulative therapy | 3 |
| Maxillofacial surgery | 2 |
| Nuclear medicine | 2 |
| Certified clinical nurse specialist | 2 |
| Medical Genetics and Genomics | 2 |
| Micrographic Dermatologic Surgery | 2 |
| Mammography Screening Center | 1 |
| Unknown physician specialty | 1 |
| Preventive medicine | 1 |
| Slide Preparation Facilities | 1 |
| Epileptologists | 1 |
| Advanced Heart Failure and Transplant Cardiology | 1 |
| Psychologist (billing independently) | 1 |
| Dentist | 1 |
| Oral and Maxillofacial Pathology | 1 |