| Nurse practitioner | 838 |
| Internal medicine | 523 |
| Physician assistant | 354 |
| Family practice | 270 |
| Physical therapist (private practice) | 253 |
| Certified Registered Nurse Anesthetist (CRNA) | 189 |
| Anesthesiology | 187 |
| Emergency medicine | 161 |
| Licensed clinical social worker | 160 |
| Obstetrics/gynecology | 139 |
| Chiropractic | 111 |
| Centralized Flu | 111 |
| Clinical psychologist | 107 |
| Diagnostic Radiology | 107 |
| Optometrist | 99 |
| Cardiology | 88 |
| Mental Health Counselors | 84 |
| Orthopedic surgery | 79 |
| Mass Immunization Roster Billers | 77 |
| Podiatry | 74 |
| Ophthalmology | 68 |
| Gastroenterology | 64 |
| General surgery | 64 |
| Dermatology | 61 |
| Anesthesiologist Assistant | 59 |
| Psychiatry | 59 |
| Neurology | 55 |
| Occupational therapist (private practice) | 54 |
| Nephrology | 53 |
| General practice | 52 |
| Physical medicine and rehabilitation | 46 |
| Pulmonary disease | 44 |
| Hematology/oncology | 43 |
| Urology | 41 |
| Pathology | 38 |
| Otolaryngology | 38 |
| Critical care (intensivists) | 37 |
| Endocrinology | 34 |
| Infectious disease | 33 |
| Neurosurgery | 28 |
| Plastic and reconstructive surgery | 24 |
| Rheumatology | 23 |
| Pediatric medicine | 20 |
| Vascular surgery | 20 |
| Radiation oncology | 19 |
| Hospitalist | 19 |
| Interventional radiology | 18 |
| Pain Management | 18 |
| Marriage and Family Therapist | 17 |
| Speech / language pathology | 16 |
| Thoracic surgery | 15 |
| Independent Diagnostic Testing Facility (IDTF) | 15 |
| Colorectal surgery (formerly proctology) | 15 |
| Registered Dietician/Nutrition Professional | 14 |
| Interventional Cardiology | 14 |
| Ambulatory Surgical Center | 14 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 12 |
| Cardiac Electrophysiology | 12 |
| Allergy/immunology | 12 |
| Audiologist (billing independently) | 11 |
| Pharmacy | 9 |
| Certified nurse midwife | 8 |
| Hand surgery | 7 |
| Micrographic Dermatologic Surgery | 6 |
| Geriatric medicine | 6 |
| Osteopathic manipulative therapy | 6 |
| Clinical Laboratory (Billing Independently) | 5 |
| Sports Medicine | 5 |
| Interventional Pain Management (IPM) | 5 |
| Gynecologist/oncologist | 5 |
| Oral surgery (dentists only) | 5 |
| Hospice and Palliative Care | 5 |
| Advanced Heart Failure and Transplant Cardiology | 4 |
| Surgical oncology | 4 |
| Psychologist (billing independently) | 3 |
| Cardiac surgery | 3 |
| Medical oncology | 3 |
| Maxillofacial surgery | 3 |
| Home Infusion Therapy Services | 2 |
| Medical Genetics and Genomics | 2 |
| Mammography Screening Center | 2 |
| Peripheral vascular disease | 2 |
| Opioid Treatment Program | 2 |
| Hematology | 2 |
| Neuropsychiatry | 1 |
| Unknown physician specialty | 1 |
| Certified clinical nurse specialist | 1 |