| Nurse practitioner | 1,043 |
| Physical therapist (private practice) | 777 |
| Family practice | 737 |
| Physician assistant | 695 |
| Internal medicine | 439 |
| Anesthesiology | 349 |
| Hospitalist | 273 |
| Emergency medicine | 270 |
| Chiropractic | 220 |
| Optometrist | 212 |
| Diagnostic Radiology | 205 |
| Licensed clinical social worker | 175 |
| Certified Registered Nurse Anesthetist (CRNA) | 164 |
| Clinical psychologist | 158 |
| Obstetrics/gynecology | 155 |
| Psychiatry | 151 |
| Mental Health Counselors | 147 |
| Neurology | 140 |
| Orthopedic surgery | 114 |
| Ophthalmology | 113 |
| Gastroenterology | 104 |
| General surgery | 101 |
| Dermatology | 99 |
| Pathology | 92 |
| Hematology/oncology | 89 |
| Cardiology | 88 |
| Mass Immunization Roster Billers | 82 |
| Occupational therapist (private practice) | 79 |
| Pediatric medicine | 74 |
| Pulmonary disease | 74 |
| Infectious disease | 73 |
| Urology | 69 |
| Physical medicine and rehabilitation | 67 |
| Otolaryngology | 67 |
| Podiatry | 64 |
| Nephrology | 55 |
| Audiologist (billing independently) | 52 |
| Rheumatology | 44 |
| Radiation oncology | 41 |
| Critical care (intensivists) | 37 |
| Endocrinology | 35 |
| Neurosurgery | 35 |
| Medical oncology | 34 |
| Interventional Cardiology | 33 |
| Ambulatory Surgical Center | 28 |
| Registered Dietician/Nutrition Professional | 26 |
| Centralized Flu | 24 |
| Certified nurse midwife | 24 |
| Sports Medicine | 23 |
| Allergy/immunology | 22 |
| Marriage and Family Therapist | 21 |
| Hospice and Palliative Care | 18 |
| Vascular surgery | 18 |
| Cardiac Electrophysiology | 18 |
| General practice | 17 |
| Interventional radiology | 17 |
| Speech / language pathology | 16 |
| Sleep Medicine | 16 |
| Plastic and reconstructive surgery | 14 |
| Thoracic surgery | 13 |
| Hand surgery | 13 |
| Pain Management | 13 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 13 |
| Geriatric medicine | 11 |
| Epileptologists | 11 |
| Pharmacy | 11 |
| Hematology | 10 |
| Advanced Heart Failure and Transplant Cardiology | 10 |
| Clinical Laboratory (Billing Independently) | 10 |
| Colorectal surgery (formerly proctology) | 9 |
| Interventional Pain Management (IPM) | 8 |
| Oral surgery (dentists only) | 8 |
| Independent Diagnostic Testing Facility (IDTF) | 8 |
| Gynecologist/oncologist | 8 |
| Nuclear medicine | 7 |
| Medical Genetics and Genomics | 7 |
| Adult Congenital Heart Disease | 7 |
| Surgical oncology | 6 |
| Opioid Treatment Program | 5 |
| General Psychiatry | 5 |
| Dentist | 4 |
| Unknown Provider | 4 |
| Cardiac surgery | 4 |
| Osteopathic manipulative therapy | 3 |
| Unknown physician specialty | 3 |
| Neuropsychiatry | 3 |
| Addiction medicine | 2 |
| Portable X-Ray Supplier (Billing Independently) | 2 |
| Psychologist (billing independently) | 2 |
| Preventive medicine | 2 |
| Micrographic Dermatologic Surgery | 2 |
| Oral Medicine | 1 |
| Public Health or Welfare Agencies (Federal, State, and local) | 1 |
| Orofacial Pain | 1 |
| Maxillofacial surgery | 1 |