| Internal medicine | 1,284 |
| Family practice | 783 |
| Nurse practitioner | 759 |
| Emergency medicine | 609 |
| Physician assistant | 597 |
| Physical therapist (private practice) | 502 |
| Anesthesiology | 426 |
| Psychiatry | 350 |
| Obstetrics/gynecology | 343 |
| Clinical psychologist | 343 |
| Optometrist | 304 |
| Diagnostic Radiology | 287 |
| Chiropractic | 248 |
| Licensed clinical social worker | 225 |
| Ophthalmology | 199 |
| Marriage and Family Therapist | 195 |
| Orthopedic surgery | 166 |
| Neurology | 161 |
| General surgery | 159 |
| Hospitalist | 157 |
| Dermatology | 147 |
| Podiatry | 141 |
| Gastroenterology | 138 |
| Cardiology | 132 |
| Certified Registered Nurse Anesthetist (CRNA) | 119 |
| Mass Immunization Roster Billers | 108 |
| Hematology/oncology | 98 |
| Pathology | 89 |
| Otolaryngology | 89 |
| Nephrology | 86 |
| Urology | 85 |
| Pulmonary disease | 81 |
| Physical medicine and rehabilitation | 78 |
| Critical care (intensivists) | 71 |
| Endocrinology | 66 |
| Occupational therapist (private practice) | 57 |
| Infectious disease | 53 |
| Centralized Flu | 52 |
| Rheumatology | 45 |
| Pediatric medicine | 45 |
| Radiation oncology | 41 |
| Allergy/immunology | 41 |
| Plastic and reconstructive surgery | 40 |
| Vascular surgery | 38 |
| Ambulatory Surgical Center | 37 |
| Neurosurgery | 36 |
| Hospice and Palliative Care | 31 |
| Audiologist (billing independently) | 30 |
| Registered Dietician/Nutrition Professional | 28 |
| General practice | 25 |
| Medical oncology | 24 |
| Interventional Cardiology | 22 |
| Interventional radiology | 22 |
| Speech / language pathology | 21 |
| Nuclear medicine | 20 |
| Thoracic surgery | 17 |
| Pain Management | 17 |
| Mental Health Counselors | 17 |
| Certified nurse midwife | 16 |
| Sports Medicine | 14 |
| Psychologist (billing independently) | 14 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 13 |
| Clinical Laboratory (Billing Independently) | 13 |
| Sleep Medicine | 12 |
| Cardiac Electrophysiology | 12 |
| Hand surgery | 11 |
| Colorectal surgery (formerly proctology) | 11 |
| Cardiac surgery | 11 |
| Pharmacy | 11 |
| Hematology | 11 |
| Interventional Pain Management (IPM) | 10 |
| Independent Diagnostic Testing Facility (IDTF) | 10 |
| Surgical oncology | 9 |
| Oral surgery (dentists only) | 9 |
| Opioid Treatment Program | 8 |
| Gynecologist/oncologist | 7 |
| Geriatric medicine | 7 |
| Addiction medicine | 7 |
| Osteopathic manipulative therapy | 3 |
| Unknown physician specialty | 3 |
| Maxillofacial surgery | 3 |
| Preventive medicine | 3 |
| Micrographic Dermatologic Surgery | 2 |
| Neuropsychiatry | 2 |
| General Psychiatry | 2 |
| Dentist | 2 |
| Advanced Heart Failure and Transplant Cardiology | 2 |
| Home Infusion Therapy Services | 1 |
| Portable X-Ray Supplier (Billing Independently) | 1 |
| Peripheral vascular disease | 1 |
| Medical Genetics and Genomics | 1 |
| Slide Preparation Facilities | 1 |