| Nurse practitioner | 1,276 |
| Physician assistant | 619 |
| Family practice | 463 |
| Certified Registered Nurse Anesthetist (CRNA) | 399 |
| Internal medicine | 355 |
| Physical therapist (private practice) | 280 |
| Emergency medicine | 208 |
| Mass Immunization Roster Billers | 156 |
| Anesthesiology | 133 |
| Mental Health Counselors | 129 |
| Optometrist | 122 |
| General surgery | 112 |
| Licensed clinical social worker | 104 |
| Diagnostic Radiology | 102 |
| Psychiatry | 95 |
| Obstetrics/gynecology | 89 |
| Chiropractic | 84 |
| Orthopedic surgery | 83 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 77 |
| Clinical psychologist | 73 |
| Hospitalist | 70 |
| Cardiology | 67 |
| Neurology | 60 |
| Podiatry | 53 |
| Pediatric medicine | 51 |
| Pulmonary disease | 46 |
| Ophthalmology | 46 |
| Gastroenterology | 44 |
| Hematology/oncology | 42 |
| Pathology | 41 |
| Urology | 38 |
| Centralized Flu | 38 |
| Occupational therapist (private practice) | 33 |
| Audiologist (billing independently) | 33 |
| Endocrinology | 29 |
| Otolaryngology | 28 |
| Infectious disease | 28 |
| General practice | 25 |
| Nephrology | 24 |
| Speech / language pathology | 21 |
| Neurosurgery | 21 |
| Dermatology | 20 |
| Interventional Cardiology | 19 |
| Thoracic surgery | 19 |
| Critical care (intensivists) | 18 |
| Vascular surgery | 18 |
| Psychologist (billing independently) | 17 |
| Physical medicine and rehabilitation | 17 |
| Plastic and reconstructive surgery | 16 |
| Pharmacy | 14 |
| Radiation oncology | 14 |
| Rheumatology | 13 |
| Certified nurse midwife | 13 |
| Medical oncology | 12 |
| Pain Management | 10 |
| Registered Dietician/Nutrition Professional | 10 |
| Cardiac Electrophysiology | 8 |
| Allergy/immunology | 8 |
| Clinical Laboratory (Billing Independently) | 6 |
| Opioid Treatment Program | 6 |
| Cardiac surgery | 6 |
| Ambulatory Surgical Center | 6 |
| Osteopathic manipulative therapy | 5 |
| Addiction medicine | 5 |
| Hospice and Palliative Care | 5 |
| Interventional Pain Management (IPM) | 4 |
| Sports Medicine | 4 |
| Maxillofacial surgery | 4 |
| Interventional radiology | 4 |
| Marriage and Family Therapist | 4 |
| Independent Diagnostic Testing Facility (IDTF) | 4 |
| Hematology | 4 |
| Gynecologist/oncologist | 3 |
| Geriatric medicine | 3 |
| Surgical oncology | 3 |
| Advanced Heart Failure and Transplant Cardiology | 3 |
| Home Infusion Therapy Services | 2 |
| Micrographic Dermatologic Surgery | 2 |
| Anesthesiologist Assistant | 1 |
| Unknown Provider | 1 |
| Hand surgery | 1 |
| Medical Genetics and Genomics | 1 |
| Dentist | 1 |
| Preventive medicine | 1 |
| Neuropsychiatry | 1 |
| Unknown physician specialty | 1 |
| Public Health or Welfare Agencies (Federal, State, and local) | 1 |
| Colorectal surgery (formerly proctology) | 1 |