| Nurse practitioner | 2,236 |
| Physician assistant | 979 |
| Internal medicine | 793 |
| Certified Registered Nurse Anesthetist (CRNA) | 557 |
| Family practice | 501 |
| Emergency medicine | 374 |
| Physical therapist (private practice) | 365 |
| Anesthesiology | 322 |
| Diagnostic Radiology | 263 |
| Obstetrics/gynecology | 248 |
| Licensed clinical social worker | 245 |
| Hospitalist | 226 |
| Chiropractic | 216 |
| Mental Health Counselors | 197 |
| Anesthesiologist Assistant | 175 |
| Optometrist | 166 |
| General surgery | 165 |
| Psychiatry | 154 |
| Centralized Flu | 153 |
| Cardiology | 146 |
| Pathology | 139 |
| Orthopedic surgery | 131 |
| Mass Immunization Roster Billers | 124 |
| Neurology | 124 |
| Clinical psychologist | 119 |
| Gastroenterology | 114 |
| Ophthalmology | 110 |
| General practice | 109 |
| Podiatry | 106 |
| Occupational therapist (private practice) | 94 |
| Dermatology | 87 |
| Hematology/oncology | 78 |
| Urology | 76 |
| Otolaryngology | 75 |
| Pulmonary disease | 75 |
| Nephrology | 65 |
| Infectious disease | 62 |
| Speech / language pathology | 57 |
| Critical care (intensivists) | 57 |
| Audiologist (billing independently) | 57 |
| Radiation oncology | 55 |
| Neurosurgery | 53 |
| Physical medicine and rehabilitation | 52 |
| Ambulatory Surgical Center | 52 |
| Pediatric medicine | 51 |
| Interventional Cardiology | 51 |
| Medical oncology | 50 |
| Endocrinology | 46 |
| Rheumatology | 34 |
| Registered Dietician/Nutrition Professional | 34 |
| Plastic and reconstructive surgery | 32 |
| Vascular surgery | 30 |
| Interventional Pain Management (IPM) | 30 |
| Thoracic surgery | 28 |
| Allergy/immunology | 27 |
| Pharmacy | 26 |
| Cardiac Electrophysiology | 22 |
| Hospice and Palliative Care | 22 |
| Interventional radiology | 21 |
| Certified nurse midwife | 20 |
| Marriage and Family Therapist | 20 |
| Pain Management | 19 |
| Independent Diagnostic Testing Facility (IDTF) | 17 |
| Sports Medicine | 17 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 14 |
| Colorectal surgery (formerly proctology) | 13 |
| Hand surgery | 11 |
| Clinical Laboratory (Billing Independently) | 10 |
| Hematology | 9 |
| Gynecologist/oncologist | 9 |
| Advanced Heart Failure and Transplant Cardiology | 9 |
| Opioid Treatment Program | 8 |
| Surgical oncology | 8 |
| Preventive medicine | 6 |
| Cardiac surgery | 5 |
| Psychologist (billing independently) | 4 |
| Sleep Medicine | 4 |
| Osteopathic manipulative therapy | 3 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 3 |
| Micrographic Dermatologic Surgery | 3 |
| Certified clinical nurse specialist | 2 |
| Home Infusion Therapy Services | 2 |
| Nuclear medicine | 2 |
| Oral surgery (dentists only) | 2 |
| Neuropsychiatry | 1 |
| Mammography Screening Center | 1 |
| Addiction medicine | 1 |
| Single or Multispecialty Clinic or Group Practice | 1 |
| Medical Genetics and Genomics | 1 |
| Medicare Diabetes Preventive Program | 1 |
| Undersea and Hyperbaric Medicine | 1 |
| Geriatric medicine | 1 |