| Nurse practitioner | 86 |
| Physician assistant | 49 |
| Physical therapist (private practice) | 45 |
| Emergency medicine | 30 |
| Internal medicine | 29 |
| Certified Registered Nurse Anesthetist (CRNA) | 24 |
| Family practice | 24 |
| Anesthesiology | 18 |
| Hospitalist | 16 |
| Chiropractic | 14 |
| Obstetrics/gynecology | 14 |
| Optometrist | 12 |
| General surgery | 11 |
| Psychiatry | 10 |
| Orthopedic surgery | 10 |
| Clinical psychologist | 9 |
| Licensed clinical social worker | 7 |
| Diagnostic Radiology | 6 |
| Occupational therapist (private practice) | 6 |
| Dermatology | 5 |
| Mental Health Counselors | 5 |
| Certified nurse midwife | 5 |
| Pathology | 5 |
| Podiatry | 5 |
| Plastic and reconstructive surgery | 4 |
| Infectious disease | 4 |
| Gastroenterology | 4 |
| Cardiology | 4 |
| Mass Immunization Roster Billers | 3 |
| Critical care (intensivists) | 3 |
| Audiologist (billing independently) | 3 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 3 |
| Ophthalmology | 3 |
| Ambulatory Surgical Center | 3 |
| Otolaryngology | 3 |
| Hospice and Palliative Care | 3 |
| Radiation oncology | 2 |
| Cardiac Electrophysiology | 2 |
| Physical medicine and rehabilitation | 2 |
| Medical oncology | 2 |
| Urology | 1 |
| Psychologist (billing independently) | 1 |
| Speech / language pathology | 1 |
| Nephrology | 1 |
| Sports Medicine | 1 |
| Independent Diagnostic Testing Facility (IDTF) | 1 |
| Pediatric medicine | 1 |
| Pain Management | 1 |
| Unknown physician specialty | 1 |
| Maxillofacial surgery | 1 |
| Marriage and Family Therapist | 1 |
| Thoracic surgery | 1 |
| Rheumatology | 1 |
| Osteopathic manipulative therapy | 1 |
| Opioid Treatment Program | 1 |
| Interventional Cardiology | 1 |
| Sleep Medicine | 1 |
| Centralized Flu | 1 |
| Vascular surgery | 1 |
| Pharmacy | 1 |
| Oral surgery (dentists only) | 1 |
| Pulmonary disease | 1 |
| General practice | 1 |